The following prescribing information is based on official labeling in effect July 2000.
Diclofenac, as the sodium or potassium salt, is a benzeneacetic acid derivative, designated chemically as 2-[(2,6-dichlorophenyl)amino] benzeneacetic acid, monosodium or monopotassium salt. The structural formula is shown in Figure 1.
R = K: Cataflam®, diclofenac potassium
R = Na: Voltaren® or Voltaren®-XR, diclofenac sodium
Diclofenac, as the sodium or potassium salt, is a faintly yellowish white to light beige, virtually odorless, slightly hygroscopic crystalline powder. Molecular weights of the sodium and potassium salts are 318.14 and 334.25, respectively. It is freely soluble in methanol, soluble in ethanol, and practically insoluble in chloroform and in dilute acid. Diclofenac sodium is sparingly soluble in water while diclofenac potassium is soluble in water. The n-octanol/water partition coefficient is, for both diclofenac salts, 13.4 at pH 7.4 and 1545 at pH 5.2. Both salts have a single dissociation constant (pKa) of 4.0 ± 0.2 at 25°C in water.
Diclofenac potassium is available as Cataflam Immediate-Release Tablets of 50 mg for oral administration.
CATAFLAM Inactive Ingredients: Calcium phosphate, colloidal silicon dioxide, iron oxides, magnesium stearate, microcrystalline cellulose, polyethylene glycol, povidone, sodium starch glycolate, starch, sucrose, talc, titanium dioxide.
Diclofenac sodium is available as VOLTAREN Delayed-Release (enteric-coated) Tablets of 25 mg, 50 mg, and 75 mg for oral administration, and VOLTAREN-XR Extended-Release Tablets of 100 mg.
VOLTAREN Inactive Ingredients: Hydroxypropyl methylcellulose, iron oxide, lactose, magnesium stearate, methacrylic acid copolymer, microcrystalline cellulose, polyethylene glycol, povidone, propylene glycol, sodium hydroxide, sodium starch glycolate, talc, titanium dioxide, D&C Yellow No. 10 Aluminum Lake (25-mg tablet only), FD&C Blue No. 1 Aluminum Lake (50-mg tablet only).
VOLTAREN-XR Inactive Ingredients: Cetyl alcohol, hydroxypropyl methylcellulose, iron oxide, magnesium stearate, polyethylene glycol, polysorbate, povidone, silicon dioxide, sucrose, talc, titanium dioxide.
Diclofenac, the anion in Cataflam, Voltaren, and Voltaren-XR, is a non steroidal anti-inflammatory drug (NSAID). In pharmacologic studies, diclofenac has shown anti-inflammatory, analgesic, and antipyretic activity. As with other NSAIDs, its mode of action is not known; its ability to inhibit prostaglandin synthesis, however, may be involved in its anti-inflammatory activity, as well as contribute to its efficacy in relieving pain related to inflammation and primary dysmenorrhea. With regard to its analgesic effect, diclofenac is not a narcotic.
Cataflam Immediate-Release Tablets, Voltaren Delayed-Release Tablets, and Voltaren-XR Extended-Release Tablets, contain the same therapeutic moiety, diclofenac. They differ in the cationic portion of the salt , as well as in their release characteristics. Cataflam Immediate-Release Tablets are formulated to release diclofenac in the stomach.
Voltaren Delayed-Release (enteric-coated) Tablets are in a pharmaceutical formulation that resists dissolution in the low pH of gastric fluid but allows a rapid release of drug in the higher pH-environment of the duodenum.
Conversely, Voltaren-XR Extended-Release Tablets are formulated to release drug over a prolonged period. The primary pharmacokinetic difference between the three products is in the pattern of drug release and absorption, as described below and shown in Table 1.
For this reason, separate sections are provided below to describe the different absorption profiles of Cataflam Immediate-Release Tablets, Voltaren Delayed-Release Tablets, and Voltaren-XR Extended-Release Tablets.
Under fasting condition, diclofenac is completely absorbed from the gastrointestinal tract. However, due to first-pass metabolism, only about 50% of the absorbed dose is systemically available.
Cataflam Immediate-Release Tablets: In some fasting volunteers, measurable plasma levels are observed within 10 minutes of dosing with Cataflam. Peak plasma levels are achieved in approximately 1 hour in fasting normal volunteers, with a range from 0.33 to 2 hours.
The extent of diclofenac absorption is not significantly affected when Cataflam is taken with food. However, the rate of absorption is reduced by food, as indicated by a delay in T max and decrease in C max values by approximately 30%. After repeated oral administration of Cataflam 50 mg t.i.d. no accumulation of diclofenac in plasma occurred.
Voltaren Delayed-Release Tablets: Peak plasma levels are achieved in 2 hours in fasting normal volunteers, with a range from 1 to 4 hours. The area-under-the-plasma-concentration curve (AUC) is dose-proportional within the range of 25 mg to 150 mg. Peak plasma levels are less than dose-proportional and are approximately 1.0, 1.5, and 2.0 µg/mL for 25-mg, 50-mg, and 75-mg doses, respectively. It should be noted that the administration of several individual Voltaren tablets may not yield equivalent results in peak concentration as the administration of one tablet of a higher strength. This is probably due to the staggered gastric emptying of tablets into the duodenum. After repeated oral administration of Voltaren 50 mg b.i.d., diclofenac did not accumulate in plasma.
When Voltaren is taken with food, there is usually a delay in the onset of absorption of 1 to 4.5 hours, with delays as long as 10 hours in some patients, and a reduction in peak plasma levels of approximately 40%. The extent of absorption of diclofenac, however, is not significantly affected by food intake.
Voltaren-XR Extended-Release Tablets: The extent of diclofenac absorption from the extended-release tablet is not significantly affected when the drug is taken with food, however, food significantly altered the absorption pattern as indicated by a delay of 1 to 2 hours in T max and a two-fold increase in C max values. The plasma profile of the extended-release tablet, under fasting conditions, was characterized by multiple peaks and high intersubject variability in blood profiles. In contrast, the plasma profile for the extended-release tablets under fed conditions showed a more consistent absorption pattern with a single peak usually occurring between 5 and 6 hours after the meal.
Plasma concentrations of diclofenac decline from peak levels in a biexponential fashion, with the terminal phase having a half-life of approximately 2 hours. Clearance and volume of distribution are about 350 mL/min and 550 mL/kg, respectively. More than 99% of diclofenac is reversibly bound to human plasma albumin.
As with other NSAIDs, diclofenac diffuses into and out of the synovial fluid. Diffusion into the joint occurs when plasma levels are higher than those in the synovial fluid, after which the process reverses and synovial fluid levels are higher than plasma levels. It is not known whether diffusion into the joint plays a role in the effectiveness of diclofenac.
Diclofenac is eliminated through metabolism and subsequent urinary and biliary excretion of the glucuronide and the sulfate conjugates of the metabolites. Approximately 65% of the dose is excreted in the urine, and approximately 35% in the bile.
Conjugates of unchanged diclofenac account for 5%-10% of the dose excreted in the urine and for less than 5% excreted in the bile. Little or no unchanged unconjugated drug is excreted. Conjugates of the principal metabolite account for 20%-30% of the dose excreted in the urine and for 10%-20% of the dose excreted in the bile. Conjugates of three other metabolites together account for 10%-20% of the dose excreted in the urine and for small amounts excreted in the bile. The elimination half-life values for these metabolites are shorter than those for the parent drug. Urinary excretion of an additional metabolite (half-life 80 hours) accounts for only 1.4% of the oral dose. The degree of accumulation of diclofenac metabolites is unknown. Some of the metabolites may have activity.
A 4-week study, comparing plasma level profiles of diclofenac (Voltaren 50 mg b.i.d.) in younger (26-46 years) versus older (66-81 years) adults, did not show differences between age groups (10 patients per age group).
Geriatric Population: An 8-day study, comparing the kinetics of diclofenac (100 mg Voltaren-XR q.d.) in osteoarthritis patients older than 65 years versus younger than 65 years showed no significant differences between the two groups with respect to peak plasma levels, time to peak levels, or AUC.
Patients with Renal and/or Hepatic Impairment: To date, no differences in the pharmacokinetics of diclofenac have been detected in studies of patients with renal (50 mg intravenously) or hepatic impairment (100-mg oral solution). In patients with renal impairment (N=5, creatinine clearance 3 to 42 mL/min), AUC values and elimination rates were comparable to those in healthy subjects. In patients with biopsy-confirmed cirrhosis or chronic active hepatitis (variably elevated transaminases and mildly elevated bilirubins, N=10), diclofenac concentrations and urinary elimination values were comparable to those in healthy subjects.
Cataflam Immediate-Release Tablets in Analgesia/Primary Dysmenorrhea: The analgesic efficacy of Cataflam was demonstrated in trials of patients with postoperative pain (following gynecologic, oral, and orthopedic surgery), osteoarthritis of the knee, and primary dysmenorrhea. The effectiveness of Cataflam in studies of pain or primary dysmenorrhea showed that onset of analgesia began, in some patients, as soon as 30 minutes, and relief of pain lasted as long as 8 hours, following single 50-mg or 100-mg doses. Duration of pain relief was judged by the time at which approximately half of the patients needed remedication. The onset and duration of pain relief for either the 50-mg or 100-mg dose was essentially the same, whether patients had moderate or severe pain at baseline.
Cataflam was studied in single-dose and multiple-dose pain trials. The pain models in single-dose studies were post-dental extraction and post-gynecologic surgery: the efficacy of the 50-mg dose (N=258) and the 100-mg dose (N=255) was comparable to aspirin 650 mg in onset of pain relief, but generally provided a longer duration of analgesia than aspirin. The pain models for multiple-dose trials were post-orthopedic surgery pain as well as pain associated with primary dysmenorrhea: the efficacy of the 50-mg dose (N=101) and the 100-mg dose (N=442), followed by 50 mg every 8 hours, was comparable to naproxen sodium 550 mg followed by 275 mg every 8 hours. In one study of chronic pain, in patients with osteoarthritis (N=196), Cataflam 50 mg t.i.d. was comparable in efficacy to ibuprofen 800 mg t.i.d. and Voltaren Delayed-Release Tablets 50 mg t.i.d.
Voltaren Delayed-Release Tablets in Osteoarthritis: Voltaren was evaluated for the management of the signs and symptoms of osteoarthritis of the hip or knee in a total of 633 patients treated for up to 3 months in placebo- and active-controlled clinical trials against aspirin (N=449), and naproxen (N=92). Voltaren was given both in variable (100-150 mg/day) and fixed (150 mg/day) dosing schedules in either b.i.d. or t.i.d. dosing regimens. In these trials, Voltaren was found to be comparable to 2400 to 3600 mg/day of aspirin or 500 mg/day of naproxen. Voltaren was effective when administered as either b.i.d. or t.i.d. dosing regimens.
Voltaren Delayed-Release Tablets in Rheumatoid Arthritis: Voltaren was evaluated for managing the signs and symptoms of rheumatoid arthritis in a total of 468 patients treated for up to 3 months in placebo- and active-controlled clinical trials against aspirin (N=290), and ibuprofen (N=74). Voltaren was given in a fixed (150 or 200 mg/day) dosing schedule as either b.i.d. or t.i.d. dosing regimens. Voltaren was found to be comparable to 3600 to 4800 mg/day of aspirin, and 2400 mg/day of ibuprofen. Voltaren was used b.i.d. or t.i.d., administering 150 mg/day in most trials, but 50 mg q.i.d. (200 mg/day) was also studied.
Voltaren Delayed-Release Tablets in Ankylosing Spondylitis: Voltaren was evaluated for the management of the signs and symptoms of ankylosing spondylitis in a total of 132 patients in one active-controlled clinical trial against indomethacin (N=130). Both Voltaren and indomethacin patients were started on 25 mg t.i.d. and were permitted to increase the dose 25 mg/day each week to a maximum dose of 125 mg/day. Voltaren 75-125 mg/day was found to be comparable to indomethacin 75-125 mg/day.
Voltaren-XR Extended-Release Tablets in Osteoarthritis: The use of Voltaren-XR Tablets in controlling the signs and symptoms of osteoarthritis was assessed in two double-blind, controlled trials in which 742 patients participated and 517 patients were treated for 3 months. In one active- and placebo-controlled study, Voltaren-XR Tablets at doses of 100 mg q.d. were comparable to Voltaren Delayed-Release Tablets 50 mg b.i.d. in patients whose osteoarthritis symptoms were stabilized after 2 weeks of treatment with Voltaren Delayed-Release Tablets 75 mg b.i.d. In another study, Voltaren-XR Tablets at doses of 100 mg q.d. and 100 mg b.i.d. were compared to Voltaren Delayed-Release Tablets 50 mg q.i.d. Voltaren-XR Tablets 100 mg b.i.d. were comparable to Voltaren Delayed-Release Tablets 50 mg q.i.d. With the Voltaren-XR Tablet formulation, although there was a trend toward greater efficacy at doses of 200 mg daily than 100 mg daily, there was also an increase in side effects when 200 mg of Voltaren-XR Tablets were administered to patients with osteoarthritis.
Voltaren-XR Extended-Release Tablets in Rheumatoid Arthritis: The use of Voltaren-XR Tablets in controlling the signs and symptoms of rheumatoid arthritis was assessed in two double-blind, controlled trials in which 704 patients participated and 441 patients were treated for 3 months. In one active- and placebo-controlled study, Voltaren-XR Tablets 100 mg q.d. were comparable to Voltaren Delayed-Release Tablets 50 mg b.i.d. in patients whose rheumatoid arthritis symptoms were stabilized after 2 weeks' treatment of Voltaren Delayed-Release Tablets 75 mg b.i.d. In another study, Voltaren-XR Tablets at doses of 100 mg q.d. and 100 mg b.i.d. were compared to Voltaren Delayed-Release Tablets 50 mg q.i.d.; Voltaren-XR Tablets 100 mg b.i.d. were comparable to Voltaren Delayed-Release Tablets 50 mg q.i.d. There was a trend toward greater efficacy with doses of 200 mg daily as compared to 100 mg daily of Voltaren-XR Tablets. There was also an increase in side effects when200 mg of Voltaren-XR Tablets were administered to patients with rheumatoid arthritis.
Special Studies (The clinical significance of the findings outlined below is unknown.)
G.I. Blood Loss/Endoscopy Data: G.I. blood loss and endoscopy studies were performed with Voltaren Delayed-Release (enteric-coated) Tablets that, unlike Immediate-Release Tablets, do not dissolve in the stomach where the endoscopic lesions are primarily seen; Cataflam Immediate-Release Tablets have not been similarly studied. A repeat-dose endoscopy study, in patients with rheumatoid arthritis or osteoarthritis treated with Voltaren Delayed-Release Tablets 75 mg b.i.d. (N=101), or naproxen (immediate-release tablets) 500 mg b.i.d. (N=103) for 3 months, resulted in a significantly smaller number of patients with an increase in endoscopy score from baseline and a significantly lower mean endoscopy score after treatment in the Voltaren-treated patients. Two repeat-dose endoscopic studies, in normal volunteers showed that daily doses of Voltaren Delayed-Release Tablets 75 or 100 mg (N=6 and N=14, respectively) for 1 week caused fewer gastric lesions, and those that did occur had lower scores than those observed following daily 500-mg doses of naproxen (immediate-release tablets). In healthy subjects, the daily administration of 150 mg of Voltaren (N=8) for 3 weeks resulted in a mean fecal blood loss less than that observed with 3.0 g of aspirin daily (N=8). In four repeat-dose studies, mean fecal blood loss with 150 mg of Voltaren was also less than that observed with 750 mg of naproxen (N=8 and N=6) or 150 mg of indomethacin (N=8 and N=6).
Diclofenac, like other NSAIDs, shows interindividual differences in both pharmacokinetics and clinical response (pharmacodynamics). Consequently, the recommended strategy for initiating therapy is to use a starting dose likely to be effective for the majority of patients and to adjust dosage thereafter based on observation of diclofenac' beneficial and adverse effects.
In patients weighing less than 60 kg (132 lb), or where the severity of the disease, concomitant medication, or other diseases warrant, the maximum recommended total daily dose of Cataflam, Voltaren, or Voltaren-XR should be reduced. Experience with other NSAIDs has shown that starting therapy with maximum doses in patients at increased risk due to renal or hepatic disease, low body weight (<60 kg), advanced age, a known ulcer diathesis, or known sensitivity to NSAID effects, is likely to increase frequency of adverse reactions and is not recommended (see PRECAUTIONS ).
Osteoarthritis/Rheumatoid Arthritis/Ankylosing Spondylitis: The usual starting dose of Cataflam Immediate-Release Tablets or Voltaren Delayed-Release for patients with osteoarthritis, is 100 to 150 mg/day, using a b.i.d. or t.i.d. dosing regimen. For patients with osteoarthritis, the usual starting dose of Voltaren-XR Extended-Release Tablets is 100 mg q.d. In two variable-dose clinical trials in osteoarthritis using Voltaren Delayed-Release Tablets, of 266 patients started on 100 mg/day, 176 chose to increase the dose to 150 mg/day. Dosages above 200 mg/day have not been studied in patients with osteoarthritis.
For most patients with rheumatoid arthritis, the usual starting dose of Cataflam Immediate-Release Tablets or Voltaren Delayed-Release Tablets is 150 mg/day, using a b.i.d. or t.i.d. dosing regimen. The usual starting dose of Voltaren-XR Extended-Release Tablets is 100 mg q.d. Patients requiring more relief of pain and inflammation may increase the dose to 200 mg/day. In clinical trials, patients receiving 200 mg/day were less likely to drop from the trial due to lack of efficacy than patients receiving 150 mg/day as Voltaren Delayed-Release Tablets or 100 mg/day as Voltaren-XR Extended-Release Tablets. Dosages above 225 mg/day are not recommended in patients with rheumatoid arthritis because of increased risk of adverse events.
The recommended dose of Voltaren Delayed-Release Tablets for patients with ankylosing spondylitis is 100 to 125 mg/day, using a q.i.d. dosing regimen (see DOSAGE AND ADMINISTRATION regarding the 125 mg/day dosing regimen). In a variable-dose clinical trial, of 132 patients started on 75 mg/day, 122 chose to increase the dose to 125 mg/day. Dosages above 125 mg/day have not been studied in patients with ankylosing spondylitis.
Analgesia/Primary Dysmenorrhea: Because of earlier absorption of diclofenac from Cataflam Immediate-Release Tablets, it is the formulation indicated for management of pain and primary dysmenorrhea when prompt onset of pain relief is desired. The results of clinical trials suggest an initial Cataflam dose of 50 mg for pain or for primary dysmenorrhea, followed by doses of 50 mg every 8 hours, as needed. With experience, some patients with recurring pain, such as dysmenorrhea, may find that an initial dose of 100 mg of Cataflam, followed by 50-mg doses, will provide better relief. After the first day, when the maximum recommended dose may be 200 mg, the total daily dose should generally not exceed 150 mg.
Cataflam Immediate-Release Tablets and Voltaren Delayed-Release Tablets are indicated for the acute and chronic treatment of signs and symptoms of osteoarthritis and rheumatoid arthritis. Voltaren-XR Extended-Release Tablets are indicated for chronic therapy of osteoarthritis and rheumatoid arthritis. In addition, Cataflam Immediate-Release Tablets and Voltaren Delayed-Release Tablets are indicated for the treatment of ankylosing spondylitis. Only Cataflam is indicated for the management of pain and primary dysmenorrhea, when prompt pain relief is desired, because it is formulated to provide earlier plasma concentrations of diclofenac (see , and Clinical Studies ).
Diclofenac in all formulations, Cataflam, Voltaren, and Voltaren-XR, is contraindicated in patients with known hypersensitivity to diclofenac and diclofenac-containing products. Diclofenac should not be given to patients who have experienced asthma, urticaria, or other allergic-type reactions after taking aspirin or other NSAIDs. Severe, rarely fatal, anaphylactic-like reactions to diclofenac have been reported in such patients (see -- Anaphylactoid Reactions , and PRECAUTIONS -- Preexisting Asthma ).
Peptic ulceration and gastrointestinal bleeding have been reported in patients receiving diclofenac. Physicians and patients should therefore remain alert for ulceration and bleeding in patients treated chronically with diclofenac even in the absence of previous G.I. tract symptoms. It is recommended that patients be maintained on the lowest dose of diclofenac possible, consistent with achieving a satisfactory therapeutic response.
Risk of G.I. Ulcerations, Bleeding, and Perforation with NSAID Therapy: Serious gastrointestinal toxicity such as bleeding, ulceration, and perforation can occur at any time, with or without warning symptoms, in patients treated chronically with NSAID therapy. Although minor upper gastrointestinal problems, such as dyspepsia, are common, usually developing early in therapy, physicians should remain alert for ulceration and bleeding in patients treated chronically with NSAIDs even in the absence of previous G.I. tract symptoms. In patients observed in clinical trials of several months to 2 years' duration, symptomatic upper G.I. ulcers, gross bleeding, or perforation appear to occur in approximately 1% of patients for 3-6 months, and in about 2%-4% of patients treated for 1 year. Physicians should inform patients about the signs and/or symptoms of serious G.I. toxicity and what steps to take if they occur.
Studies to date have not identified any subset of patients not at risk of developing peptic ulceration and bleeding. Except for a prior history of serious G.I. events and other risk factors known to be associated with peptic ulcer disease, such as alcoholism, smoking, etc., no risk factors (e.g., age, sex) have been associated with increased risk. Elderly or debilitated patients seem to tolerate ulceration or bleeding less well than other individuals, and most spontaneous reports of fatal G.I. events are in this population. Studies to date are inconclusive concerning the relative risk of various NSAIDs in causing such reactions. High doses of any NSAID probably carry a greater risk of these reactions, although controlled clinical trials showing this do not exist in most cases. In considering the use of relatively large doses (within the recommended dosage range), sufficient benefit should be anticipated to offset the potential increased risk of G.I. toxicity.
Elevations of one or more liver tests may occur during diclofenac therapy. These laboratory abnormalities may progress, may remain unchanged, or may be transient with continued therapy. Borderline elevations (i.e., less than 3 times the ULN [=the Upper Limit of the Normal range]), or greater elevations of transaminases occurred in about 15% of diclofenac-treated patients. Of the hepatic enzymes, ALT (SGPT) is the one recommended for the monitoring of liver injury.
In clinical trials, meaningful elevations (i.e., more than 3 times the ULN) of AST (SGOT) (ALT was not measured in all studies) occurred in about 2% of approximately 5700 patients at some time during Voltaren treatment. In a large, open, controlled trial, meaningful elevations of ALT and/or AST occurred in about 4% of 3700 patients treated for 2-6 months, including marked elevations (i.e., more than 8 times the ULN) in about 1% of the 3700 patients. In that open-label study, a higher incidence of borderline (less than 3 times the ULN), moderate (3-8 times the ULN), and marked (>8 times the ULN) elevations of ALT or AST was observed in patients receiving diclofenac when compared to other NSAIDs. Transaminase elevations were seen more frequently in patients with osteoarthritis than in those with rheumatoid arthritis (see ADVERSE REACTIONS ).
In addition to enzyme elevations seen in clinical trials, postmarketing surveillance has found rare cases of severe hepatic reactions, including liver necrosis, jaundice, and fulminant fatal hepatitis with and without jaundice. Some of these rare reported cases underwent liver transplantation.
Physicians should measure transaminases periodically in patients receiving long-term therapy with diclofenac, because severe hepatotoxicity may develop without a prodrome of distinguishing symptoms. The optimum times for making the first and subsequent transaminase measurements are not known. In the largest U.S. trial (open-label) that involved 3700 patients monitored first at 8 weeks and 1200 patients monitored again at 24 weeks, almost all meaningful elevations in transaminases were detected before patients became symptomatic. In 42 of the 51 patients in all trials who developed marked transaminase elevations, abnormal tests occurred during the first 2 months of therapy with diclofenac. Postmarketing experience has shown severe hepatic reactions can occur at any time during treatment with diclofenac. Cases of drug-induced hepatotoxicity have been reported in the first month, and in some cases, the first two months of therapy. Based on these experiences, transaminases should be monitored within 4 to 8 weeks after initiating treatment with diclofenac (see PRECAUTIONS -- Laboratory Tests ). As with other NSAIDs, if abnormal liver tests persist or worsen, if clinical signs and/or symptoms consistent with liver disease develop, or if systemic manifestations occur (e.g., eosinophilia, rash, etc.), diclofenac should be discontinued immediately.
To minimize the possibility that hepatic injury will become severe between transaminase measurements, physicians should inform patients of the warning signs and symptoms of hepatotoxicity (e.g., nausea, fatigue, lethargy, pruritus, jaundice, right upper quadrant tenderness, and "flu-like" symptoms), and the appropriate action patients should take if these signs and symptoms appear.
As with other NSAIDs, anaphylactoid reactions may occur in patients without prior exposure to diclofenac. Diclofenac should not be given to patients with the aspirin triad. The triad typically occurs in asthmatic patients who experience rhinitis with or without nasal polyps, or who exhibit severe, potentially fatal bronchospasm after taking aspirin or other nonsteroidal anti-inflammatory drugs. Fatal reactions have been reported in such patients (see CONTRAINDICATIONS , and PRECAUTIONS -- Preexisting Asthma ). Emergency help should be sought in cases where an anaphylactoid reaction occurs.
In cases with advanced kidney disease, treatment with diclofenac, as with other NSAIDs, should only be initiated with close monitoring of the patient's kidney functions (see PRECAUTIONS -- Renal Effects ).
In late pregnancy, diclofenac should, as with other NSAIDs, be avoided because it will cause premature closure of the ductus arteriosus (see PRECAUTIONS -- Pregnancy, Teratogenic Effects, Pregnancy Category B , and Labor and Delivery ).
Cataflam Immediate-Release Tablets, Voltaren Delayed-Release Tablets, and Voltaren-XR Extended-Release Tablets should not be used concomitantly with other diclofenac-containing products since they also circulate in plasma as the diclofenac anion.
Fluid Retention and Edema: Fluid retention and edema have been observed in some patients taking diclofenac. Therefore, as with other NSAIDs, diclofenac should be used with caution in patients with a history of cardiac decompensation, hypertension, or other conditions predisposing to fluid retention.
Hematologic Effects: Anemia is sometimes seen in patients receiving diclofenac or other NSAIDs. This may be due to fluid retention, G.I. blood loss, or an incompletely described effect upon erythropoiesis.
Renal Effects: As a class, NSAIDs have been associated with renal papillary necrosis and other abnormal renal pathology in long-term administration to animals. In oral diclofenac studies in animals, some evidence of renal toxicity was noted. Isolated incidents of papillary necrosis were observed in a few animals at high doses (20-120 mg/kg) in several baboon subacute studies. In patients treated with diclofenac, rare cases of interstitial nephritis and papillary necrosis have been reported (see ADVERSE REACTIONS ).
A second form of renal toxicity, generally associated with NSAIDs, is seen in patients with conditions leading to a reduction in renal blood flow or blood volume, where renal prostaglandins have a supportive role in the maintenance of renal perfusion. In these patients, administration of an NSAID results in a dose-dependent decrease in prostaglandin synthesis and, secondarily, in a reduction of renal blood flow, which may precipitate overt renal failure. Patients at greatest risk of this reaction are those with impaired renal function, heart failure, liver dysfunction, those taking diuretics, and the elderly. Discontinua tion of NSAID therapy is typically followed by recovery to the pretreatment state.
Cases of significant renal failure in patients receiving diclofenac have been reported from marketing experience, but were not observed in over 4000 patients in clinical trials during which serum creatinine and BUN values were followed serially. There were only 11 patients (0.3%) whose serum creatinine and concurrent serum BUN values were greater than 2.0 mg/dL and 40 mg/dL, respectively, while on diclofenac (mean rise in the 11 patients: creatinine 2.3 mg/dL and BUN 28.4 mg/dL).
Since diclofenac metabolites are eliminated primarily by the kidneys, patients with significantly impaired renal function should be more closely monitored than subjects with normal renal function.
Porphyria: The use of diclofenac in patients with hepatic porphyria should be avoided. To date, 1 patient has been described in whom diclofenac probably triggered a clinical attack of porphyria. The postulated mechanism, demonstrated in rats, for causing such attacks by diclofenac, as well as some other NSAIDs, is through stimulation of the porphyrin precursor delta-aminolevulinic acid (ALA).
Aseptic Meningitis: As with other NSAIDs, aseptic meningitis with fever and coma has been observed on rare occasions in patients on diclofenac therapy. Although it is probably more likely to occur in patients with systemic lupus erythematosus and related connective tissue diseases, it has been reported in patients who do not have an underlying chronic disease. If signs or symptoms of meningitis develop in a patient on diclofenac, the possibility of its being related to diclofenac should be considered.
Preexisting Asthma: About 10% of patients with asthma may have aspirin-sensitive asthma. The use of aspirin in patients with aspirin-sensitive asthma has been associated with severe bronchospasm which can be fatal. Since cross-reactivity, including bronchospasm, between aspirin and other nonsteroidal anti-inflammatory drugs has been reported in such aspirin-sensitive patients, diclofenac should not be administered to patients with this form of aspirin sensitivity and should be used with caution in all patients with preexisting asthma.
Other Precautions: The pharmacologic activity of diclofenac may reduce fever and inflammation, thus diminishing their utility as diagnostic signs in detecting underlying conditions.
In order to avoid exacerbation of manifestations of adrenal insufficiency, patients who have been on prolonged corticosteroid treatment should have their therapy tapered slowly rather than discontinued abruptly when diclofenac is added to the treatment program.
Blurred and/or diminished vision, scotomata, and/or changes in color vision have been reported. If a patient develops such complaints while receiving diclofenac, the drug should be discontinued and the patient should have an ophthalmologic examination which includes central visual fields and color vision testing.
Diclofenac, like other drugs of its class, is not free of side effects. The side effects of these drugs can cause discomfort and, rarely, more serious side effects, such as gastrointestinal bleeding, and more rarely, liver toxicity (see , Hepatic Effects ), which may result in hospitalization and even fatal outcomes.
NSAIDs are often essential agents in the management of arthritis and have a major role in the management of pain, but they also may be commonly employed for conditions that are less serious.
Physicians may wish to discuss with their patients the potential risks (see , PRECAUTIONS , and ADVERSE REACTIONS ) and likely benefits of NSAID treatment, particularly when the drugs are used for less serious conditions where treatment without NSAIDs may represent an acceptable alternative to both the patient and physician.
Because serious G.I. tract ulceration and bleeding can occur without warning symptoms, physicians should follow chronically treated patients for the signs and symptoms of ulceration and bleeding and should inform them of the importance of this follow-up (see , Gastrointestinal Effects , Risk of G.I. Ulcerations, Bleeding, and Perforation with NSAID Therapy) . If diclofenac is used chronically, patients should also be instructed to report any signs and symptoms that might be due to hepatotoxicity of diclofenac; these symptoms may become evident between visits when periodic liver laboratory tests are performed (see , Hepatic Effects , and PRECAUTIONS -- Laboratory Tests ).
Hepatic Effects: Transaminases and other hepatic enzymes should be monitored in patients treated with NSAIDs. For patients on diclofenac therapy, it is recommended that a determination be made within 4 weeks of initiating therapy and at intervals thereafter. If clinical signs and symptoms consistent with liver disease develop, or if systemic manifestations occur (e.g. eosinophilia, rash, etc.) and abnormal liver tests are detected, persist or worsen, diclofenac should be discontinued immediately.
Hematologic Effects: Patients on long-term treatment with NSAIDs, including diclofenac, should have their hemoglobin or hematocrit checked periodically for signs or symptoms of anemia. Appropriate measures should be taken in case such signs of anemia occur.
Aspirin Concomitant administration of diclofenac and aspirin is not recommended because diclofenac is displaced from its binding sites during the concomitant administration of aspirin, resulting in lower plasma concentrations, peak plasma levels, and AUC values.
Anticoagulants: While studies have not shown diclofenac to interact with anticoagulants of the warfarin type, caution should be exercised, nonetheless, since interactions have been seen with other NSAIDs. Because prostaglandins play an important role in hemostasis, and NSAIDs affect platelet function as well, concurrent therapy with all NSAIDs, including diclofenac, and warfarin requires close monitoring of patients to be certain that no change in their anticoagulant dosage is required.
Digoxin, Methotrexate, Cyclosporine: Diclofenac, like other NSAIDs, may affect renal prostaglandins and increase the toxicity of certain drugs. Ingestion of diclofenac may increase serum concentrations of digoxin and methotrexate and increase cyclosporine' nephrotoxicity. Patients who begin taking diclofenac or who increase their diclofenac dose or any other NSAID while taking digoxin, methotrexate, or cyclosporine may develop toxicity characteristics for these drugs. They should be observed closely, particularly if renal function is impaired. In the case of digoxin, serum levels should be monitored.
Lithium Diclofenac decreases lithium renal clearance and increases lithium plasma levels. In patients taking diclofenac and lithium concomitantly, lithium toxicity may develop.
Oral Hypoglycemics: Diclofenac does not alter glucose metabolism in normal subjects nor does it alter the effects of oral hypoglycemic agents. There are rare reports, however, from marketing experiences, of changes in effects of insulin or oral hypoglycemic agents in the presence of diclofenac that necessitated changes in the doses of such agents. Both hypo- and hyperglycemic effects have been reported. A direct causal relationship has not been established, but physicians should consider the possibility that diclofenac may alter a diabetic patient' response to insulin or oral hypoglycemic agents.
Diuretics: Diclofenac and other NSAIDs can inhibit the activity of diuretics. Concomitant treatment with potassium-sparing diuretics may be associated with increased serum potassium levels.
Other Drugs: In small groups of patients (7-10/interaction study), the concomitant administration of azathioprine, gold, chloroquine, D-penicillamine, prednisolone, doxycycline, or digitoxin did not significantly affect the peak levels and AUC values of diclofenac. Phenobarbital toxicity has been reported to have occurred in a patient on chronic phenobarbital treatment following the initiation of diclofenac therapy.
In vitro, diclofenac interferes minimally or not at all with the protein binding of salicylic acid (20% decrease in binding), tolbutamide, prednisolone (10% decrease in binding), or warfarin. Benzylpenicillin, ampicillin, oxacillin, chlorte-tracycline, doxycycline, cephalothin, erythromycin, and sulfamethoxazole have no influence in vitro on the protein binding of diclofenac in human serum.
Effect on Blood Coagulation: Diclofenac increases platelet aggregation time but does not affect bleeding time, plasma thrombin clotting time, plasma fibrinogen, or factors V and VII to XII. Statistically significant changes in prothrombin and partial thromboplastin times have been reported in normal volunteers. The mean changes were observed to be less than 1 second in both instances, however, and are unlikely to be clinically important. Diclofenac is a prostaglandin synthetase inhibitor, however, and all drugs that inhibit prostaglandin synthesis interfere with platelet function to some degree; therefore, patients who may be adversely affected by such an action should be carefully observed.
Long-term carcinogenicity studies in rats given diclofenac sodium up to 2 mg/kg/day (or 12 mg/m 2 /day, approximately the human dose) have revealed no significant increases in tumor incidence. There was a slight increase in benign mammary fibroadenomas in mid-dose-treated (0.5 mg/kg/day or 3 mg/m 2 /day) female rats (high-dose females had excessive mortality), but the increase was not significant for this common rat tumor. A 2-year carcinogenicity study conducted in mice employing diclofenac sodium at doses up to 0.3 mg/kg/day (0.9 mg/m 2 /day) in males and 1 mg/kg/day (3 mg/m 2 /day) in females did not reveal any oncogenic potential. Diclofenac sodium did not show mutagenic activity in in vitro point mutation assays in mammalian (mouse lymphoma) and microbial (yeast, Ames) test systems and was nonmutagenic in several mammalian in vitro and in vivo tests, including dominant lethal and male germinal epithelial chromosomal studies in mice, and nucleus anomaly and chromosomal aberration studies in Chinese hamsters. Diclofenac sodium administered to male and female rats at 4 mg/kg/day (24-mg/m 2 /day) did not affect fertility.
Reproduction studies have been performed in mice given diclofenac sodium (up to 20 mg/kg/day or 60 mg/m 2 /day) and in rats and rabbits given diclofenac sodium (up to 10 mg/kg/day or 60 mg/m 2 /day for rats, and 80 mg/m 2 /day for rabbits), and have revealed no evidence of teratogenicity despite the induction of maternal toxicity and fetal toxicity. In rats, maternally toxic doses were associated with dystocia, prolonged gestation, reduced fetal weights and growth, and reduced fetal survival. Diclofenac has been shown to cross the placental barrier in mice and rats. There are, however, no adequate and well-controlled studies in pregnant women. Because animal reproduction studies are not always predictive of human response, this drug should not be used during pregnancy unless the benefits to the mother justify the potential risk to the fetus. Because of the risk to the fetus resulting in premature closure of the ductus arteriosus, diclofenac should be avoided in late pregnancy.
The effects of diclofenac on labor and delivery in pregnant women are unknown. Because of the known effects of prostaglandin-inhibiting drugs on the fetal cardiovascular system (closure of ductus arteriosus), use of diclofenac during late pregnancy should be avoided and, as with other nonsteroidal anti-inflammatory drugs, it is possible that diclofenac may inhibit uterine contractions and delay parturition.
Because of the potential for serious adverse reactions in nursing infants from diclofenac, a decision should be made whether to discontinue nursing or to discontinue the drug, taking into account the importance of the drug to the mother.
Safety and effectiveness of diclofenac in pediatric patients have not been established.
Of the more than 6000 patients treated with diclofenac in U.S. trials, 31% were older than 65 years of age. No overall difference was observed between efficacy, adverse event, or pharmacokinetic profiles of older and younger patients. As with any NSAID, the elderly are likely to tolerate adverse reactions less well than younger patients.
Adverse reaction information is derived from blinded, controlled, and open-label clinical trials, as well as worldwide marketing experience. In the description below, rates of more common events represent clinical study results; rarer events are derived principally from marketing experience and publications, and accurate rate estimates are generally not possible.
In 718 patients treated for shorter periods, i.e., 2 weeks or less, with Cataflam Immediate-Release Tablets, adverse reactions were reported one-half to one-tenth as frequently as by patients treated for longer periods. In a 6-month, double-blind trial comparing Cataflam Immediate-Release Tablets (N=196) versus Voltaren Delayed-Release Tablets (N=197) versus ibuprofen (N=197), adverse reactions were similar in nature and frequency. In controlled clinical trials, the incidence of adverse reactions for Voltaren Delayed-Release Tablets and Voltaren-XR Extended-Release Tablets at comparable doses were similar.
The incidence of common adverse reactions (greater than 1%) is based upon controlled clinical trials in 1543 patients treated up to 13 weeks with Voltaren Delayed-Release Tablets. By far the most common adverse effects were gastrointestinal symptoms, most of them minor, occurring in about 20%, and leading to discontinuation in about 3%, of patients. Peptic ulcer or G.I. bleeding occurred in clinical trials in 0.6% (95% confidence interval: 0.2% to 1%) of approximately 1800 patients during their first 3 months of diclofenac treatment and in 1.6% (95% confidence interval: 0.8% to 2.4%) of approximately 800 patients followed for 1 year.
Gastrointestinal symptoms were followed in frequency by central nervous system side effects such as headache (7%) and dizziness (3%).
Meaningful (exceeding 3 times the Upper Limit of Normal) elevations of ALT (SGPT) or AST (SGOT) occurred at an overall rate of approximately 2% during the first 2 months of Voltaren treatment. Unlike aspirin-related elevations, which occur more frequently in patients with rheumatoid arthritis, these elevations were more frequently observed in patients with osteoarthritis (2.6%) than in patients with rheumatoid arthritis (0.7%). Marked elevations (exceeding 8 times the ULN) were seen in 1% of patients treated for 2-6 months (see , Hepatic Effects ).
The following adverse reactions were reported in patients treated with diclofenac:
(All derived from clinical trials.)
*Incidence, 3% to 9% (incidence of unmarked reactions is 1%-3%).
Body as a Whole: Abdominal pain or cramps,* headache,* fluid retention, abdominal distention.
Digestive: Diarrhea,* indigestion,* nausea,* constipation,* flatulence, liver test abnormalities,* PUB, i.e., peptic ulcer, with or without bleeding and/or perforation, or bleeding without ulcer (see above and also ).
Nervous System: Dizziness.
Skin and Appendages: Rash, pruritus.
Special Senses: Tinnitus.
(Adverse reactions reported only in worldwide marketing experience or in the literature, not seen in clinical trials, are considered rare and are italicized .)
Body as a Whole: Malaise, swelling of lips and tongue, photosensitivity, anaphylaxis , anaphylactoid reactions.
Cardiovascular Hypertension, congestive heart failure.
Digestive: Vomiting, jaundice, melena, esophageal lesions , aphthous stomatitis, dry mouth and mucous membranes, bloody diarrhea, hepatitis, hepatic necrosis, cirrhosis, hepatorenal syndrome , appetite change, pancreatitis with or without concomitant hepatitis, colitis.
Hemic and Lymphatic: Hemoglobin decrease, leukopenia, thrombocytopenia, eosinophilia, hemolytic anemia, aplastic anemia, agranulocytosis , purpura, allergic purpura .
Metabolic and Nutritional Disorders: Azotemia.
Nervous System: Insomnia, drowsiness, depression, diplopia, anxiety, irritability, aseptic meningitis, convulsions .
Respiratory Epistaxis, asthma, laryngeal edema.
Skin and Appendages: Alopecia, urticaria, eczema, dermatitis, bullous eruption, erythema multiforme major , angioedema, Stevens-Johnson syndrome .
Special Senses: Blurred vision, taste disorder, reversible and irreversible hearing loss, scotoma.
Urogenital: Nephrotic syndrome, proteinuria, oliguria, interstitial nephritis, papillary necrosis, acute renal failure.
(The following reactions have been reported in patients taking diclofenac under circumstances that do not permit a clear attribution of the reaction to diclofenac. These reactions are being included as alerting information to physicians. Adverse reactions reported only in worldwide marketing experience or in the literature, not seen in clinical trials, are considered rare and are italicized .)
Body as a Whole: Chest pain.
Cardiovascular: Palpitations, flushing , tachycardia, premature ventricular contractions, myocardial infarction, hypotension .
Digestive: Intestinal perforation.
Hemic and Lymphatic: Bruising .
Metabolic and Nutritional Disorders: Hypoglycemia, weight loss .
Nervous System: Paresthesia, memory disturbance, nightmares, tremor, tic, abnormal coordination, disorientation, psychotic reaction .
Respiratory Dyspnea, hyperventilation, edema of pharynx.
Skin and Appendages: Excess perspiration, exfoliative dermatitis .
Special Senses: Vitreous floaters, night blindness, amblyopia.
Urogenital: Urinary frequency, nocturia, hematuria, impotence, vaginal bleeding.
Worldwide reports of overdosage with diclofenac cover 66 cases. In approximately one-half of these reports of overdosage, concomitant medications were also taken. The highest dose of diclofenac was 5.0 g in a 17-year-old male who suffered loss of consciousness, increased intracranial pressure, aspiration pneumonitis, and died 2 days after overdose. The next highest doses of diclofenac were 4.0 g and 3.75 g. The 24-year-old female who took 4.0 g and the 28- and 42-year-old females, each of whom took 3.75 g, did not develop any clinically significant signs or symptoms. However, there was a report of a 17-year-old female who experienced vomiting and drowsiness after an overdose of 2.37 g of diclofenac.
Animal LD 50 values show a wide range of susceptibilities to acute overdosage, with primates being more resistant to acute toxicity than rodents (LD 50 in mg/kg-rats, 55; dogs, 500; monkeys, 3200).
In case of acute overdosage, it is recommended that the stomach be emptied by vomiting or lavage. Forced diuresis may theoretically be beneficial because the drug is excreted in the urine. The effect of dialysis or hemoperfusion in the elimination of diclofenac (99% protein-bound: see ) remains unproven. In addition to supportive measures, the use of oral activated charcoal may help to reduce the absorption of diclofenac.
Diclofenac may be administered as 50-mg Cataflam Immediate-Release Tablets, as 25-mg, 50-mg, and 75-mg Voltaren Delayed-Release Tablets, or as 100-mg Voltaren-XR Extended-Release Tablets. Cataflam Immediate-Release Tablets is the formulation indicated for management of acute pain and primary dysmenorrhea when prompt onset of pain relief is desired because of earlier absorption of diclofenac. For the same reason, Voltaren-XR is not indicated for the management of acute painful conditions and should be used as chronic therapy in patients with osteoarthritis and rheumatoid arthritis.
The dosage of diclofenac should be individualized to the lowest effective dose to minimize adverse effects (see INDIVIDUALIZATION OF DOSAGE ).
Osteoarthritis: The recommended dosage is 100 to 150 mg/day: Cataflam or Voltaren Delayed-Release 50 mg b.i.d. or t.i.d.; or Voltaren Delayed-Release 75 mg b.i.d. The recommended dosage for chronic therapy with Voltaren-XR is 100 mg q.d. Dosages of Voltaren-XR Extended-Release Tablets of 200 mg daily are not recommended for patients with osteoarthritis. Dosages above 200 mg/day have not been studied in patients with osteoarthritis.
Rheumatoid Arthritis: The recommended dosage is 100 to 200 mg/day: Cataflam or Voltaren Delayed-Release 50 mg t.i.d. or q.i.d.; or Voltaren Delayed-Release 75 mg b.i.d. The recommended dosage for chronic therapy with Voltaren-XR is 100 mg q.d. In the rare patient where Voltaren-XR 100 mg/day is unsatisfactory, the dose may be increased to 100 mg b.i.d. if the benefits outweigh the clinical risks. Dosages above 225 mg/day are not recommended in patients with rheumatoid arthritis.
Ankylosing Spondylitis: The recommended dosage is 100 to 125 mg/day: Voltaren 25 mg q.i.d. with an extra 25-mg dose at bedtime if necessary. Dosages above 125 mg/day have not been studied in patients with ankylosing spondylitis.
Analgesia and Primary Dysmenorrhea: The recommended starting dose of Cataflam Immediate-Release Tablets is 50 mg t.i.d. With experience, physicians may find that in some patients an initial dose of 100 mg of Cataflam, followed by 50-mg doses, will provide better relief. After the first day, when the maximum recommended dose may be 200 mg, the total daily dose should generally not exceed 150 mg.
50 mg - light brown, round, biconvex (imprinted CATAFLAM on one side and 50 on the other side)
Bottles of 100 ................................ NDC 0028-0151-01
Unit Dose (blister pack)
Box of 100 (strips of 10) .............. NDC 0028-0151-61
25 mg - yellow, biconvex, triangular-shaped (imprinted VOLTAREN 25 on one side)
Bottles of 60 .................................. NDC 0028-0258-60
Bottles of 100 ................................ NDC 0028-0258-01
Unit Dose (blister pack)
Box of 100 (strips of 10) .............. NDC 0028-0258-61
50 mg - light brown, biconvex, triangular-shaped (imprinted VOLTAREN 50 on one side)
Bottles of 60 .................................. NDC 0028-0262-60
Bottles of 100 ................................ NDC 0028-0262-01
Bottles of 1000 .............................. NDC 0028-0262-10
Unit Dose (blister pack)
Box of 100 (strips of 10) .............. NDC 0028-0262-61
75 mg - light pink, biconvex, triangular-shaped (imprinted VOLTAREN 75 on one side)
Bottles of 60 .................................. NDC 0028-0264-60
Bottles of 100 ................................ NDC 0028-0264-01
Bottles of 1000 .............................. NDC 0028-0264-10
Unit Dose (blister pack)
Box of 100 (strips of 10) .............. NDC 0028-0264-61
100 mg - light pink, coated, round, biconvex with beveled edges (imprinted Voltaren-XR on one side and 100 on the other side)
Bottles of 100 ................................ NDC 0028-0205-01
Unit Dose (blister pack)
Box of 100 (strips of 10) .............. NDC 0028-0205-61
Do not store above 30°C (86°F). Protect from moisture. Dispense in tight container (USP).
REV: MAY 2000
Novartis Pharmaceuticals Corporation
East Hanover, New Jersey 07936