Griseofulvin

Griseofulvin is a metabolic product of Penicillium spp. It was the first available oral agent for the treatment of dermatophytoses and has now been used for more than forty years. Griseofulvin is fongistatic, the exact mechanism in witch it inhibits the growth of dermatophytes is doubtful. Several ways are invoked: inhibition of fungal cell mitosis and nuclear acid synthesis, probable interference with the function of microtubules. Griseofulvin is poorly absorbed from the gastrointestinal tract. Absorption is enhanced by administration with fatty meal. Peak plasma occurs four hours after oral administration. Griseofulvin is detected in the outer layer of the stratum corneum soon after it is ingested, it is diffused from the extracellular fluid and sweat. There is no information regarding the mechanism by witch the drug is delivered to nails and hair. Deposition in the newly formed cells could be the major factor. Griseofulvin has also anti-inflammatory properties and some direct vasodilatory effects when it is used in high doses. It is metabolised by the liver microsomial enzyme system and excreted in the urine. The half-life is 9 to 21 hours. Griseofulvine has been used in the therapy of dermatophyte onychomycosis, treatment periods from 6 to 18 months were necessary with disappointing results and numerous relapses. Newer oral antifungal agents are now preferred especially in toenail infections. For many authors griseofulvin is still the treatment of choice of tinea capitis. Doses are 15-20 mg/kg/d for 6 to 8 weeks in children with the microsized form. Clinical response rates have been reported between 80 and 90 p. 100 in controlled studies. Griseofulvin is well-tolerated particulary in children. More frequent side effects are minor: headaches, gastrointestinal reactions and cutaneous eruptions. The major drug interactions has been noted with phenobarbital, anticoagulants and oral contraceptives.