Griseofulvin

INDICASTIONS AND USAGE Griseofulvin tablets, USP are 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 crateriform 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 …

• Accurate diagnosis of the infecting organism is essential
• Identification should be made either by direct microscopic examination of a mounting of infected tissue in a solution of potassium hydroxide or by culture on an appropriate medium
• Medication must be continued until the infecting organism is completely eradicated as indicated by appropriate clinical or laboratory examination
• Representative treatment periods are tinea capitis, 4 to 6 weeks; tinea corporis, 2 to 4 weeks; tinea pedis, 4 to 8 weeks; tinea unguium – depending on rate of growth – fingernails, at least 4 months; toenails, at least 6 months
• General measures in regard to hygiene should be observed to control sources of infection or reinfection
• Concomitant use of appropriate topical agents is usually required, particularly in treatment of tinea pedis
• In some forms of tinea pedis, yeasts and bacteria may be involved as well as dermatophytes
• Griseofulvin tablets, USP will not eradicate hese associated bacterial or yeast infections
• ADULTS : 0.5 g daily (125 mg q.i.d., 250 mg b.i.d., or 500 mg/day)
• Patients with less severe or 300 extensive infections may require less, whereas those with widespread lesions may require a starting dose of 0.75 g to 1 g/day
• This may be reduced gradually to 0.5 g or less after a response has been noted
• In all cases, the dosage should be individualized
• PEDIATRIC PATIENTS (older than 2 years): A dosage of 10 mg/kg daily is usually adequate (pediatric patients from 30 to 50 lb, 125 mg to 250 mg daily; pediatric patients over 50 lb, 250 mg to 500 mg daily, in divided doses). …

• 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

• 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. …

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. …

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. …

There have been post-marketing 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. …

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

There is limited experience on overdose with griseofulvin. In case of overdosage, discontinue medication, treat symptomatically and institute supportive measures as required.

Take it when you remember, unless it is nearly time for the next dose. Then skip the missed one. Never take two doses at once to make up for it. Check your leaflet, as some medicines are different.