Indications And Clinical Uses: Orally effective against superficial infections caused by those fungi responsible for dermatomycoses in man and animals, namely: M. canis, M. gypseum, M. audouini, E. floccosum, T. tonsurans, T. rubrum, T. mentagrophytes, T. magnini, T. gallinae, T. verrucosum, T. sulfureum, T. interdigitale, T. schoenleini, T. crateriform. Griseofulvin is inactive against: C. albicans (monilia), C. neoformans, B. dermatitidis, A. israeli, H. capsulatum, C. immitis, M. furfur (tinea versicolor) and bacteria. The drug is useful in the treatment of fungal infections of the scalp and those of the glabrous skin. The drug is less effective in chronic infections of the feet, palms, and nails. Since these chronic fungal infections tend to cause hyperkeratosis, concomitant topical keratolytic therapy is almost always necessary.
Contra-Indications: Porphyria, hepatocellular failure, and individuals with a history of hypersensitivity to griseofulvin. The exacerbation of systemic lupus erythematosus has been reported in patients treated with griseofulvin. Not recommended in pregnancy or in minor or trivial infections which will respond to topical antifungal agents alone.
Pregnancy: Griseofulvin may have harmful effects on the genotype. For this reason, it is recommended that male persons who are treated with griseofulvin not father children during the next 6 months after termination of the treatment. Female persons should not become pregnant during the treatment with griseofulvin.
Precautions: As with all antibiotics, the use of this drug may result in an overgrowth of nonsusceptible organisms particularly monilia. Periodic blood cell counts should be done during griseofulvin therapy, and its administration should be discontinued if granulocytopenia occurs. Albuminuria and hyaline casts have been associated with the use of griseofulvin, but renal function tests have revealed no impairment. The urine of patients on prolonged therapy should be examined for porphobilinogen. Since griseofulvin is derived from a species of penicillin, the possibility of cross sensitivity with penicillin exists; however, known penicillin sensitive patients have been treated without difficulty.
As griseofulvin may alter prothrombin activity in some patients, it is recommended that prothrombin times be determined at least 2 or 3 times a week with patients on anticoagulant therapy if griseofulvin is added to the regimen.
Concomitant administration of phenobarbital and griseofulvin may result in reduced blood levels of griseofulvin due to the enzymatic acceleration of griseofulvin metabolism. During therapy with griseofulvin, patients should be advised to avoid exposure to intense natural or artificial sunlight. Griseofulvin has also been reported as interfering with the efficacy of oral contraceptives. Patients should be warned that an enhancement of the effects of alcohol by griseofulvin has been reported.
Occupational Hazards: In those rare cases where individuals are affected by drowsiness while taking griseofulvin, they should not drive vehicles or operate machinery.
Long-term administration of high doses of griseofulvin with food has been reported to induce hepatomas in mice and thyroid tumors in rats but not hamsters. The clinical significance of these findings is not known. In view of these data, griseofulvin tablets should not be used prophylactically. There is no doubt that griseofulvin is capable of inducing aneuploidy (abnormal segregation of chromosomes following cell division) in mammalian cells exposed to the compound in vitro. In the absence of the relevant in vivo data, it is prudent to warn men that they should not father children within 6 months of treatment.
Adverse Reactions: Severe reactions occur infrequently. Headache may occur, but usually disappears when the drug is taken with meals. Nausea, epigastric distress, heartburn, abdominal cramps, vomiting or diarrhea have been reported in a few patients. Chest pain, dryness of the mouth, breathlessness, arthralgia, neuritic pains, vertigo, and fever have also been reported. Allergic reactions, occurring rarely, include urticaria and angioneurotic edema, skin rashes, serum sickness, lupus erythematosus. Fatigue, lethargy, vertigo, decreased mental acuity, dizziness, confusion, peripheral neuropathy and secondary monilial skin infections have been reported as well as a few cases of photosensitivity. Toxic epidermal necrolysis and erythema multiforme have been reported. Proteinuria and leukopenia have been reported rarely. If granulocytopenia occurs, the administration of the drug should be discontinued. In children receiving griseofulvin, enlargement of the breast and hyperpigmentation of mammary areolae, nipples and external genitalia have been reported.
Dosage: Dosage should be taken after meals, otherwise absorption is likely to be inadequate. Dosage must be individualized. Adults: 500 mg daily. Children: A dosage of 10 mg/kg is usually adequate (children from 14 to 23 kg, 125 to 250 mg daily; children over 23 kg, 250 to 500 mg, in divided doses). Patients with less severe infections may require less, whereas those with widespread lesions may require a starting dose of 0.75 to 1 g/day. Therapy should be continued for at least 2 weeks after all signs of infection have disappeared.
Availability And Storage: Each scored tablet contains: microcrystalline griseofulvin 250 mg. Energy: 0.63 kJ (0.15 kcal). Sodium:
GRISOVIN® FP Roberts Griseofulvin Microcrystalline Antifungal Antibiotic