Grisofulvin

Griseofulvin oral suspension is indicated for the treatment of dermatophyte infections of the skin not adequately treated by topical therapy, hair and nails, namely: Tinea corporis Tinea pedis Tinea cruris Tinea barbae Tinea capitis Tinea unguium when caused by one or more of the following species of fungi: Epidermophyton floccosum Microsporum audouinii Microsporum canis Microsporum gypseum Trichophyton crateriformis Trichophyton gallinae Trichophyton interdigitalis Trichophyton megnini Trichophyton mentagrophytes Trichophyton rubrum Trichophyton schoenleini Trichophyton sulphureum Trichophyton tonsurans Trichophyton verrucosum Note: Prior to therapy, a dermatophyte should be identified as responsible for the infection. Prior to initiating treatment, appropriate specimens for laboratory testing (KOH preparation, fungal culture, or nail biopsy) should be obtained to confirm the diagnosis. Griseofulvin is not effective in the following: Bacterial infections Coccidioidomycosis Candidiasis (Moniliasis) North American Blastomycosis Histoplasmosis Cryptococcosis (Torulosis) Actinomycosis Tinea versicolor Sporotrichosis Nocardiosis Chromoblastomycosis The use of this drug is not justified in minor or trivial dermatophyte infections which will respond to topical agents alone.

Griseofulvin is contraindicated in patients with porphyria or hepatocellular failure, and in individuals with a history of hypersensitivity to griseofulvin. Griseofulvin may cause fetal harm when administered to a pregnant woman. Two published cases of conjoined twins have been reported in patients taking griseofulvin during the first trimester of pregnancy, therefore, griseofulvin is contraindicated in women who are or may become pregnant during treatment. Women taking estrogen-containing oral contraceptives may be at increased risk of becoming pregnant while on griseofulvin (see also PRECAUTIONS, Drug Interactions ). If this drug is used during pregnancy, or if the patient becomes pregnant while taking this drug, the patient should be apprised of the potential hazard to the fetus. Although no direct causal relationship has been established, spontaneous abortion has been reported rarely coincident with the use of griseofulvin. Note: The Maximum Recommended Human Dose (MRHD) was set at 500 mg/day for the multiple of human exposure calculations performed in this label. If higher doses than 500 mg/day were used clinically, then the multiple of human exposure would be correspondingly reduced for that dose. For example, if a 1000 mg/day dose was administered to an individual, then the multiple of human exposure would be reduced by a factor of 2. Griseofulvin has been shown to be embryotoxic and teratogenic in pregnant rats when given at a daily oral dose of 250 mg/kg/day [4X the Maximum Recommended Human Dose (MRHD) based on Body Surface Area (BSA)]. Griseofulvin also has been shown to be embryotoxic and teratogenic in pregnant cats treated weekly with griseofulvin at doses of 500 to 1000 mg/week. There are reports of teratogenicity in a Golden Retriever when doses of 750 mg/day [1.2X the MRHD based on BSA] were administered for four weeks prior to and throughout the pregnancy, and in a study in which beagles were administered 35 mg/kg/day [1.9X the MRHD based on BSA] for intervals from one week up to the entire gestation period. Teratogenicity was also seen in mice when griseofulvin was administered in doses equivalent to 5 g/kg/day [40X the MRHD based on BSA] for 2 consecutive days at various stages of the pregnancy.

Prophylactic Usage Safety and efficacy of griseofulvin for prophylaxis of fungal infections have not been established. Serious Skin Reactions Severe skin reactions (e.g. Stevens-Johnson syndrome, toxic epidermal necrolysis) and erythema multiforme have been reported with griseofulvin use. These reactions may be serious and may result in hospitalization or death. If severe skin reactions occur, griseofulvin should be discontinued (see ADVERSE REACTIONS section). Hepatotoxicity Elevations in AST, ALT, bilirubin, and jaundice have been reported with griseofulvin use. These reactions may be serious and may result in hospitalization or death. Patients should be monitored for hepatic adverse events and discontinuation of griseofulvin considered if warranted (see ADVERSE REACTIONS section).

General Patients on prolonged therapy with any potent medication should be under close observation. Periodic monitoring of organ system function, including renal, hepatic and hematopoietic, should be done. Since griseofulvin is derived from species of penicillin, the possibility of cross sensitivity with penicillin exists; however, known penicillin-sensitive patients have been treated without difficulty. Lupus erythematosus, lupus-like syndromes or exacerbation of existing lupus erythematosus have been reported in patients receiving griseofulvin. Since a photosensitivity reaction is occasionally associated with griseofulvin therapy, patients should be warned to avoid exposure to intense or prolonged natural or artificial sunlight. Drug Interactions Griseofulvin has been reported in the literature to interfere with the metabolism of various compounds. Whether this is due to a P-450 mediated enzyme induction effects on sulfurtransferase and/or glucotransferase activity, or some other mechanism is unknown. Griseofulvin decreases the activity of warfarin-type anticoagulants, so that patients receiving these drugs concomitantly may require dosage adjustment of the anticoagulant during and after griseofulvin therapy. Griseofulvin may enhance the hepatic metabolism of estrogens, including the estrogen component of oral contraceptives, thereby reducing the effectiveness of contraception and causing menstrual irregularities. Therefore, an alternate or second form of birth control may be indicated during periods of concurrent use (see also CONTRAINDICATIONS ). Cyclosporine levels may be reduced when administered concomitantly with griseofulvin, resulting in a decrease in the pharmacologic effects of cyclosporine. Serum salicylate concentrations may be decreased when griseofulvin is given concomitantly with salicylates. Barbiturates usually depress griseofulvin activity by decreasing plasma levels and concomitant administration may require a dosage adjustment of the antifungal agent. Nausea, vomiting, flushing, tachycardia, and severe hypotension have been reported following alcohol ingestion during griseofulvin therapy. Carcinogenesis, Mutagenesis, Impairment of Fertility In subacute toxicity studies, orally administered griseofulvin produced hepatocellular necrosis in mice, but this has not been seen in other species. Chronic feeding of griseofulvin, at levels ranging from 0.5 to 2.5% of the diet, resulted in the development of liver tumors in several strains of mice, particularly in males. Smaller particle sizes resulted in an enhanced effect. Lower oral-dosage levels have not been tested. Subcutaneous administration of relatively small doses of griseofulvin once a week during the first three weeks of life has also been reported to induce hepatomata in mice. Thyroid tumors, mostly adenomas but some carcinomas, have been reported in male rats receiving griseofulvin at levels of 2%, 1% and 0.2% of the diet, and in female rats receiving the two higher dose levels. Studies in other animal species were inadequate assessments of tumorigenicity. Disturbances in porphyrin metabolism have been reported in griseofulvin-treated laboratory animals. Griseofulvin has been reported to have a colchicine-like effect on mitosis and was cocarcinogenic with methylcholanthrene in cutaneous tumor induction in laboratory animals. Griseofulvin interferes with chromosomal distribution during cell division, causing aneuploidy in plant and mammalian cells. These effects have been demonstrated in vitro at concentrations that may be achieved in the serum with the recommended therapeutic dosage. Suppression of spermatogenesis has been reported to occur in rats and sperm abnormalities have been observed in griseofulvin treated mice, but these were not detected in man. Male patients should wait at least six months after completing griseofulvin therapy before fathering a child. Pregnancy Teratogenic Effects Pregnancy Category X See CONTRAINDICATIONS and PRECAUTIONS, Drug Interactions . Nursing Mothers It is not known if griseofulvin is excreted in human milk. Because many drugs are excreted in human milk and because of the potential for tumorigenicity shown for griseofulvin in animal studies (see PRECAUTIONS, Carcinogenesis, Mutagenesis, Impairment of Fertility ), 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. Pediatric Use Safety and effectiveness in pediatric patients 2 years of age and younger have not been established. Safety in pediatric patients older than 2 years of age at dosages greater than 10 mg/kg daily has not been established.

There have been postmarketing reports of severe skin and hepatic adverse events associated with griseofulvin use (see WARNINGS section). When adverse reactions occur, they are most commonly of the hypersensitivity type, such as skin rashes, urticaria, and rarely, angioneurotic edema, and erythema multiforme. These may necessitate withdrawal of therapy and appropriate countermeasures. Peripheral neuropathy and paresthesias of the hands and feet have been reported and may be related to treatment duration. Most patients treated with griseofulvin for less than six months experienced improvement or resolution of their neuropathy upon withdrawal of the griseofulvin. Other side effects reported occasionally are oral thrush, nausea, vomiting, epigastric distress, diarrhea, headache, fatigue, dizziness, insomnia, mental confusion, and impairment of performance of routine activities. Proteinuria, nephrosis (sometimes associated with existing systemic lupus erythematosus), leukopenia, coagulopathy, hepatitis, elevated liver enzymes, hyperbilirubinemia, and GI bleeding have been reported rarely. Administration of the drug should be discontinued if granulocytopenia occurs.

Griseofulvin has been reported in the literature to interfere with the metabolism of various compounds. Whether this is due to a P-450 mediated enzyme induction effects on sulfurtransferase and/or glucotransferase activity, or some other mechanism is unknown. Griseofulvin decreases the activity of warfarin-type anticoagulants, so that patients receiving these drugs concomitantly may require dosage adjustment of the anticoagulant during and after griseofulvin therapy. Griseofulvin may enhance the hepatic metabolism of estrogens, including the estrogen component of oral contraceptives, thereby reducing the effectiveness of contraception and causing menstrual irregularities. Therefore, an alternate or second form of birth control may be indicated during periods of concurrent use (see also CONTRAINDICATIONS ). Cyclosporine levels may be reduced when administered concomitantly with griseofulvin, resulting in a decrease in the pharmacologic effects of cyclosporine. Serum salicylate concentrations may be decreased when griseofulvin is given concomitantly with salicylates. Barbiturates usually depress griseofulvin activity by decreasing plasma levels and concomitant administration may require a dosage adjustment of the antifungal agent. Nausea, vomiting, flushing, tachycardia, and severe hypotension have been reported following alcohol ingestion during griseofulvin therapy.

Teratogenic Effects Pregnancy Category X See CONTRAINDICATIONS and PRECAUTIONS, Drug Interactions .

It is not known if griseofulvin is excreted in human milk. Because many drugs are excreted in human milk and because of the potential for tumorigenicity shown for griseofulvin in animal studies (see PRECAUTIONS, Carcinogenesis, Mutagenesis, Impairment of Fertility ), 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 in pediatric patients 2 years of age and younger have not been established. Safety in pediatric patients older than 2 years of age at dosages greater than 10 mg/kg daily has not been established.