Griseofulvin Dosage

Usual Adult Dose for Onychomycosis - Fingernail

Microsize formulation: 1000 mg/day orally in 2 to 4 divided doses

Ultramicrosize formulation: 660 to 750 mg/day orally in 2 to 4 divided doses

Usual Adult Dose for Onychomycosis - Toenail

Microsize formulation: 1000 mg/day orally in 2 to 4 divided doses

Ultramicrosize formulation: 660 to 750 mg/day orally in 2 to 4 divided doses

Usual Adult Dose for Tinea Pedis

Microsize formulation: 1000 mg/day orally in 2 to 4 divided doses

Ultramicrosize formulation: 660 to 750 mg/day orally in 2 to 4 divided doses

Usual Adult Dose for Tinea Barbae

Microsize formulation: 500 mg/day orally in single or 2 divided doses

Ultramicrosize formulation: 330 to 375 mg/day orally in single or divided doses

Usual Adult Dose for Tinea Capitis

Microsize formulation: 500 mg/day orally in single or 2 divided doses

Ultramicrosize formulation: 330 to 375 mg/day orally in single or divided doses

Usual Adult Dose for Tinea Corporis

Microsize formulation: 500 mg/day orally in single or 2 divided doses

Ultramicrosize formulation: 330 to 375 mg/day orally in single or divided doses

Usual Adult Dose for Tinea Cruris

Microsize formulation: 500 mg/day orally in single or 2 divided doses

Ultramicrosize formulation: 330 to 375 mg/day orally in single or divided doses

Usual Pediatric Dose for Dermatophytosis

Microsize formulation:
1 year or older: 10 to 20 mg/kg/day orally in single or divided doses, not to exceed 1000 mg/day

Ultramicrosize formulation:
2 years or younger: Dosage has not been established.
Greater than 2 years: 5 to 15 mg/kg/day in single or divided doses, not to exceed 750 mg/day

Renal Dose Adjustments

Data not available

Liver Dose Adjustments

The pharmacokinetics of griseofulvin in patients with liver disease have not been studied. Since griseofulvin is primarily metabolized by the liver, caution is advised when it is administered to patients with impaired hepatic function. The use of griseofulvin is contraindicated in patients with hepatocellular failure.

Precautions

Griseofulvin should not be prescribed to pregnant patients. If the patient becomes pregnant while taking this drug, she should be made aware of the potential hazard to the fetus.

Griseofulvin is contraindicated in patients with hepatocellular failure or porphyria.

Elevations in AST, ALT, bilirubin, and jaundice have been reported. These reactions may be serious and may result in hospitalization or death. Monitoring for hepatic adverse events is recommended. Griseofulvin discontinuation should be considered if necessary.

Severe skin reactions and erythema multiforme have been reported. These reactions may be serious and may result in hospitalization or death. Griseofulvin should be discontinued if severe skin reactions occur.

Hypersensitivity type reactions (such as skin rashes, urticaria, erythema multiforme-like drug reactions, and rarely, angioneurotic edema) have been reported. Such reactions may require griseofulvin discontinuation and appropriate countermeasures.

Leukopenia has been reported rarely. Griseofulvin should be discontinued if granulocytopenia occurs.

Patients on prolonged treatment with any potent medication should be under close observation. Organ system function (including liver, renal, and hematopoietic) should be assessed periodically.

Rare, serious reactions occurring with griseofulvin are usually associated with high dosages, long treatment duration, or both.

Safety and efficacy of griseofulvin for prophylaxis of fungal infections have not been determined.

Dialysis

Data not available

Other Comments

Microsized griseofulvin should be administered with a fatty meal to enhance absorption.

Patients should be advised to avoid intense natural or artificial sunlight exposure due to potential photosensitivity reactions.

Therapy must be continued until the infecting organism is completely eradicated as indicated by appropriate clinical or laboratory examination. Generally, at least 4 to 6 weeks of treatment is required for tinea capitis; at least 2 to 4 weeks for tinea barbae, tinea corporis, and tinea cruris; at least 4 to 8 weeks for tinea pedis; at least 4 months for onychomycosis of the fingernail; and at least 6 months for onychomycosis of the toenail.

General measures in regard to hygiene should be observed to control sources of infection or reinfection.

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