Griseofulvin Dosing Guidelines

Standard Adult Dosing

The British Journal of Dermatology recommends a daily dose of 500-1000mg for onychomycosis, with 1g daily being most often prescribed, though there is no certain evidence that this improves cure rates in toenail infection compared to lower doses 1, 2
The treatment duration for fingernail infections is 6-9 months and 12-18 months for toenail infections, as suggested by the British Journal of Dermatology 2, 3
For tinea capitis in adults >50kg, the recommended dose is 1g/day in single or divided doses for 6-8 weeks, according to Praxis Medical Insights 3

The British Journal of Dermatology suggests taking griseofulvin with fatty food to increase absorption and improve bioavailability 4, 5, 3
In resistant cases, doses up to 25mg/kg/day may be necessary for more prolonged periods, as recommended by the British Journal of Dermatology 4, 5, 3

The British Journal of Dermatology reports poor efficacy for nail infections, with mycological cure rates for toenail onychomycosis being only 30-40%, and high relapse rates 1, 2
Newer agents, such as terbinafine and itraconazole, have demonstrated significantly higher cure rates than griseofulvin for dermatophyte onychomycosis, and are now considered treatments of choice, according to the British Journal of Dermatology 1, 2
The lengthy treatment necessary (12-18 months for toenails) affects compliance and cost-effectiveness, despite the drug's low price, as noted by the British Journal of Dermatology 1, 2

Griseofulvin is contraindicated in pregnancy, porphyria, lupus erythematosus, and severe liver disease, as stated by the British Journal of Dermatology 4, 5
Common side effects, including gastrointestinal disturbances, headaches, and rashes, occur in 8-15% of patients, according to the British Journal of Dermatology 1, 2
Plasma concentration is decreased by rifampicin and increased by cimetidine, and it also interacts with warfarin, ciclosporin, and oral contraceptive pills, as reported by the British Journal of Dermatology and Praxis Medical Insights 1, 4, 3

The British Journal of Dermatology recommends a standard treatment of 500-1000mg daily for 6-8 weeks for Trichophyton species (tinea capitis or corporis) 6
Higher doses (up to 25mg/kg/day) may be necessary for resistant Trichophyton infections, which respond less reliably to griseofulvin than Microsporum species, with griseofulvin showing 67.9% response rates for Trichophyton compared to 88.5% for Microsporum 6

The British Journal of Dermatology suggests that griseofulvin remains highly effective for Microsporum species and is preferred over alternatives like terbinafine, with standard adult dosing (500-1000mg daily) being appropriate 6
Optimize absorption by administering griseofulvin with fatty food, which increases bioavailability, as recommended by the British Journal of Dermatology 6