MINOCIN minocycline hydrochloride, a semisynthetic derivative of tetracycline, is named [4 S -(4(alpha), 4a(alpha), 5a(alpha), 12a(alpha))]-4,7-bis(dimethylamino)-1,4,4a,5,5a,6,11,12a-octahydro-3,10,12, 12a-tetrahydroxy-1,11-dioxo-2- naphthacenecarboxamide monohydrochloride.

Its structural formula is:


C 23 H 27 N 3 O 7 ·HCl                                                                  M.W. 493.94

MINOCIN Oral Suspension contains minocycline HCl equivalent to 50 mg of minocycline per 5 mL (10 mg/mL) and the following inactive ingredients: Alcohol, Butylparaben, Calcium Hydroxide, Cellulose, Decaglyceryl Tetraoleate, Edetate Calcium Disodium, Glycol, Guar Gum, Polysorbate 80, Propylparaben, Propylene Glycol, Sodium Saccharin, Sodium Sulfite (see ) and Sorbitol.



The tetracyclines are primarily bacteriostatic and are thought to exert their antimicrobial effect by the inhibition of protein synthesis. Minocycline HCl is a tetracycline with antibacterial activity comparable to other tetracyclines with activity against a wide range of gram-negative and gram-positive organisms.

Tube dilution testing: may be considered susceptible (likely to respond to minocycline therapy) if the minimum inhibitory concentration (MIC) is not more than 4 mcg/mL. Microorganisms may be considered intermediate (harboring partial resistance) if the MIC is 4 to 12.5 mcg/mL and resistant (not likely to respond to minocycline therapy) if the MIC is greater than 12.5 mcg/mL.

Susceptibility plate testing: the Kirby-Bauer method of susceptibility testing (using a 30 mcg tetracycline disc) gives a zone of 18 mm or greater, the bacterial strain is considered to be susceptible to any tetracycline. Minocycline shows moderate in vitro activity against certain strains of staphylococci which have been found resistant to other tetracyclines. For such strains minocycline susceptibility powder may be used for additional susceptibility testing.

Human Pharmacology

Following a single dose of two 100 mg minocycline HCl capsules administered to ten normal adult volunteers, serum levels ranged from 0.74 to 4.45 mcg/mL in one hour (average 2.24), after 12 hours, they ranged from 0.34 to 2.36 mcg/mL (average 1.25). The serum half-life following a single 200 mg dose in 12 essentially normal volunteers ranged from 11 to 17 hours. In seven patients with hepatic dysfunction it ranged from 11 to 16 hours, and in 5 patients with renal dysfunction from 18 to 69 hours. The urinary and fecal recovery of minocycline when administered to 12 normal volunteers is one half to one third that of other tetracyclines.


MINOCIN is indicated in infections caused by the following microorganisms:

Rickettsiae:  (Rocky Mountain spotted fever, typhus fever and the typhus group, Q fever, rickettsialpox, tick fevers).

Mycoplasma pneumoniae (PPLO, Eaton agent).

Agents of psittacosis and ornithosis.

Agents of lymphogranuloma venereum and granuloma inguinale.

The spirochetal agent of relapsing fever ( Borrelia recurrentis ).

The following gram-negative microorganisms:

Haemophilus ducreyi chancroid

Yersinia pestis and Francisella tularensis (formerly Pasteurella pestis and Pasteurella tularensis ),

Bartonella bacilliformis ,

Bacteroides species

Vibrio comma and Vibrio fetus,

Brucella species (in conjunction with streptomycin).

Because many strains of the following groups of microorganisms have been shown to be resistant to tetracyclines, culture and susceptibility testing are recommended.

MINOCIN is indicated for treatment of infections caused by the following gram-negative microorganisms when bacteriologic testing indicates appropriate susceptibility to the drug:

Escherichia coli ,

Enterobacter aerogenes (formerly Aerobacter aerogenes ),

Shigella species,

Acinetobacter calcoaceticus (formerly Herellea, Mima),

Haemophilus influenzae (respiratory infections),

Klebsiella species (respiratory and urinary infections).

MINOCIN is indicated for treatment of infections caused by the following gram-positive microorganisms when bacteriologic testing indicates appropriate susceptibility to the drug:

Streptococcus species

Up to 44% of strains of Streptococcus pyogenes and 74% of Streptococcus faecalis have been found to be resistant to tetracycline drugs. Therefore, tetracyclines should not be used for streptococcal disease unless the organism has been demonstrated to be sensitive.

For upper respiratory infections due to Group A beta-hemolytic streptococci, penicillin is the usual drug of choice, including prophylaxis of rheumatic fever.

Streptococcus pneumoniae (formerly Diplococcus pneumoniae),

Staphylococcus aureus, skin and soft tissue infections.

Tetracyclines are not the drugs of choice in the treatment of any type of staphylococcal infection.

MINOCIN is indicated for the treatment of uncomplicated gonococcal urethritis in men due to Neisseria gonorrhoeae.

When penicillin is contraindicated, tetracyclines are alternative drugs in the treatment of infections due to:

Neisseria gonorrhoeae (in women),

Treponema pallidum and Treponema pertenue (syphilis and yaws),

Listeria monocytogenes ,

Clostridium species

Bacillus anthracis ,

Fusobacterium fusiforme (Vincent's infection),

Actinomyces species

In acute intestinal amebiasis, the tetracyclines may be a useful adjunct to amebicides.

In severe acne, the tetracyclines may be useful adjunctive therapy.

MINOCIN minocycline HCl is indicated in the treatment of trachoma, although the infectious agent is not always eliminated, as judged by immunofluorescence.

MINOCIN is indicated for the treatment of uncomplicated urethral, endocervical or rectal infections in adults caused by Chlamydia trachomatis or Ureaplasma urealyticum. 1

Inclusion conjunctivitis may be treated with oral tetracyclines or with a combination of oral and topical agents.

MINOCIN is indicated in the treatment of asymptomatic carriers of Neisseria meningitidis to eliminate meningococci from the nasopharynx.

In order to preserve the usefulness of MINOCIN in the treatment of asymptomatic meningococcal carriers, diagnostic laboratory procedures, including serotyping and susceptibility testing, should be performed to establish the carrier state and the correct treatment. It is recommended that the drug be reserved for situations in which the risk of meningococcal meningitis is high.

MINOCIN by oral administration is not indicated for the treatment of meningococcal infection.

Although no controlled clinical efficacy studies have been conducted, limited clinical data show that oral MINOCIN has been used successfully in the treatment of infections caused by Mycobacterium marinum.


This drug is contraindicated in persons who have shown hypersensitivity to any of the tetracyclines.


If renal impairment exists, even usual oral or parenteral doses may lead to excessive systemic accumulations of the drug and possible liver toxicity. Under such conditions, lower than usual total doses are indicated, and if therapy is prolonged, serum level determinations of the drug may be advisable.

Photosensitivity manifested by an exaggerated sunburn reaction has been observed in some individuals taking tetracyclines. Patients apt to be exposed to direct sunlight or ultraviolet light should be advised that this reaction can occur with tetracycline drugs, and treatment should be discontinued at the first evidence of skin erythema. Studies to date indicate that photosensitivity is rarely reported with MINOCIN minocycline HCl.

The anti-anabolic action of the tetracyclines may cause an increase in BUN. While this is not a problem in those with normal renal function, in patients with significantly impaired function, higher serum levels of tetracycline may lead to azotemia, hyperphosphatemia, and acidosis.

CNS side effects including light-headedness, dizziness, or vertigo have been reported. Patients who experience these symptoms should be cautioned about driving vehicles or using hazardous machinery while on minocycline therapy. These symptoms may disappear during therapy and usually disappear rapidly when the drug is discontinued.

MINOCIN Oral Suspension contains sodium sulfite, a sulfite that may cause allergic-type reactions including anaphylactic symptoms and life-threatening or less severe asthmatic episodes in certain susceptible people. The overall prevalence of sulfite sensitivity in the general population is unknown and probably low. Sulfite sensitivity is seen more frequently in asthmatic than in nonasthmatic people.

Usage in Pregnancy (See above about use during tooth development.)

Results of animal studies indicate that tetracyclines cross the placenta, are found in fetal tissues and can have toxic effects on the developing fetus (often related to retardation of skeletal development). Evidence of embryotoxicity has also been noted in animals treated early in pregnancy.

The safety of MINOCIN for use during pregnancy has not been established.

Usage in Newborns, Infants, and Children (See above about use during tooth development.)

All tetracyclines form a stable calcium complex in any bone forming tissue. A decrease in the fibula growth rate has been observed in prematures given oral tetracycline in doses of 25 mg/kg every six hours. This reaction was shown to be reversible when the drug was discontinued.

Tetracyclines are present in the milk of lactating women who are taking a drug in this class.



Pseudotumor cerebri (benign intracranial hypertension) in adults has been associated with the use of tetracyclines. The usual clinical manifestations are headache and blurred vision. Bulging fontanels have been associated with the use of tetracyclines in infants. While both of these conditions and related symptoms usually resolve soon after discontinuation of the tetracycline, the possibility for permanent sequelae exists.

As with other antibiotic preparations, use of this drug may result in overgrowth of nonsusceptible organisms, including fungi. If superinfection occurs, the antibiotic should be discontinued and appropriate therapy should be instituted.

In venereal diseases when coexistent syphilis is suspected, darkfield examination should be done before treatment is started and the blood serology repeated monthly for at least 4 months.

In long-term therapy, periodic laboratory evaluation of organ systems, including hematopoietic, renal and hepatic studies should be performed.

All infections due to Group A beta-hemolytic streptococci should be treated for at least ten days.

Drug Interactions

Because tetracyclines have been shown to depress plasma prothrombin activity, patients who are on anticoagulant therapy may require downward adjustment of their anticoagulant dosage.

Since bacteriostatic drugs may interfere with the bactericidal action of penicillin, it is advisable to avoid giving tetracycline in conjunction with penicillin.

Concurrent use of tetracyclines with oral contraceptives may render oral contraceptives less effective.


Gastrointestinal: Anorexia, nausea, vomiting, diarrhea, glossitis, dysphagia, enterocolitis, pancreatitis, inflammatory lesions (with monilial overgrowth) in the anogenital region and increases in liver enzymes. Rarely, hepatitis and liver failure have been reported.

These reactions have been caused by both the oral and parenteral administration of tetracyclines.

Skin: Maculopapular and erythematous rashes. Exfoliative dermatitis has been reported but is uncommon. Fixed drug eruptions, including balanitis, have been rarely reported. Erythema multiforme and rarely Stevens-Johnson syndrome have been reported. Photosensitivity is discussed above. (See . )

Pigmentation of the skin and mucous membranes has been reported.

Tooth discoloration has been reported rarely in adults.

Renal toxicity: Rise in BUN has been reported and is apparently dose related. (See .) Reversible acute renal failure has been rarely reported.

Hypersensitivity reactions: Urticaria, angioneurotic edema, polyarthralgia, anaphylaxis, anaphylactoid purpura, pericarditis, exacerbation of systemic lupus erythematosus and rarely pulmonary infiltrates with eosinophilia have been reported. A transient lupus-like syndrome has also been reported.

Blood: Hemolytic anemia, thrombocytopenia, neutropenia and eosinophilia have been reported.

CNS: (See .) Pseudotumor cerebri (benign intracranial hypertension) in adults and bulging fontanels in infants. (See PRECAUTIONS -- General . ) Headache has also been reported.

Other: When given over prolonged periods, tetracyclines have been reported to produce brown-black microscopic discoloration of the thyroid glands. Very rare cases of abnormal thyroid function have been reported.

Decreased hearing has been rarely reported in patients on MINOCIN.


Therapy should be continued for at least 24 to 48 hours after symptoms and fever have subsided.

Concomitant therapy: Antacids containing aluminum, calcium, or magnesium impair absorption and should not be given to patients taking oral tetracycline.

Studies to date have indicated that the absorption of MINOCIN is not notably influenced by foods and dairy products.

In patients with renal impairment: (See .) Total dosage should be decreased by reduction of recommended individual doses and/or extending time intervals between doses.

In the treatment of streptococcal infections, a therapeutic dose of tetracycline should be administered for at least ten days.

ADULTS: The usual dosage of MINOCIN is 200 mg initially followed by 100 mg every 12 hours.

For children above eight years of age: The usual dosage of MINOCIN minocycline HCl is 4 mg/kg initially followed by 2 mg/kg every 12 hours.

For treatment of syphilis, the usual dosage of MINOCIN should be administered over a period of 10 to 15 days. Close follow up, including laboratory tests, is recommended.

Gonorrhea patients sensitive to penicillin may be treated with MINOCIN, administered as 200 mg initially followed by 100 mg every twelve hours for a minimum of four days, with post-therapy cultures within 2 to 3 days.

In the treatment of meningococcal carrier state, recommended dosage is 100 mg every 12 hours for five days.

Mycobacterium marinum infections: Although optimal doses have not been established, 100 mg twice a day for 6 to 8 weeks have been used successfully in a limited number of cases.

Uncomplicated urethral, endocervical, or rectal infection in adults caused by Chlamydia trachomatis or Ureaplasma urealyticum: 100 mg, by mouth, 2 times a day for at least seven days. 1

In the treatment of uncomplicated gonococcal urethritis in men, 100 mg twice a day orally for five days is recommended.


MINOCIN® minocycline hydrochloride Oral Suspension contains minocycline hydrochloride equivalent to 50 mg minocycline per teaspoonful (5 mL). Preserved with propylparaben 0.10% and butylparaben 0.06% with Alcohol USP 5% v/v, Custard-flavored.

NDC 0005-5313-56                                 Bottle 2 fl. oz. (60 mL)

Store at controlled room temperature, between 20°C and 25°C (68°F and 77°F).


Animal Pharmacology and Toxicology

MINOCIN has been found to produce high blood concentrations following oral dosage to various animal species and to be extensively distributed to all tissues examined in 14 C-labeled drug studies in dogs. MINOCIN has been found experimentally to produce discoloration of the thyroid glands. This finding has been observed in rats and dogs. Changes in thyroid function have also been found in these animal species. However, no change in thyroid function has been observed in humans.

Reference: 1. CDC Sexually Transmitted Diseases Treatment Guidelines 1982.

Manufactured by:


American Cyanamid Company

Pearl River, NY 10965

CI 6016-1  Issued February 23, 1999


NOTE: These photos can be used only for identification by shape, color, and imprint. They do not depict actual or relative size.

The product samples shown here have been supplied by the manufacturer and reproduced in full color by PDR as a quick-reference identification aid. While every effort has been made to assure accurate reproduction, please remember that any visual identification should be considered preliminary. In cases of poisoning or suspected overdosage, the drug' identity should be verified by chemical analysis.