Porphyria
griseofulvin microsize
INDICATIONS & DOSAGE
Ringworm infections of skin, hair, nails (tinea corporis, tinea capitis, tinea cruris)
when due to Trichophyton, Microsporum, or Epidermophyton –
Adults: 500 mg of microsize P.O. daily in single or divided doses. Severe infections may require up to 1 g daily. Or, 330 to 375 mg ultrarnicrosize P.O. daily in single or divided doses. Duration of therapy is 2 to 8 weeks depending on site of infection.
Tinea pedis, tinea unguium
Adults: 0.75 to I g of microsize P.O. daily. Or, 660 to 750 mg of ultramicrosize P.O. daily in divided doses. Duration of therapy is 4 weeks to 1year.
Children: 11 mglkglday of microsize P.O. Or, 7.3 mg/kg/day of ultramicrosize P.O.
ADVERSE REACTIONS
CNS: headache (in early stages of treatment), fatigue (with large doses), occasional mental confusion, impaired performance of routine activities, psychotic symptoms, dizziness, insomnia, paresthesia of hands and feet (after extended therapy).
EENT: transient decrease in hearing, oral thrush.
GI: nausea, vomiting, flatulence, diarrhea, epigastric distress, bleeding.
GU: proteinuria, menstrual irregularities.
Hematologic: leukopenia, agranulocytosis, porphyria.
Hepatic: hepatic toxicity.
Skin: rash, urticaria, photosensitivity, angioedema.
Other: hypersensitivity reactions, lupus erythematosus.
INTERACTIONS
Drug-drug. Coumarin anticoagulants: decreased effectiveness. PT and INR must be monitored when used concurrently. Cyclosporine: decreased serum cyclosporine levels. Monitor closely.
Oral contraceptives: decreased effectiveness. Alternative methods of contraception should be suggested.
Phenobarbital: decreased griseofulvin
blood levels due to decreased absorption or increased metabolism. Avoid using together or griseofulvin is administered t.i.d.
Drug-food. High-fat meals: increased absorption. Drug and meal are administered together.
Drug-lifestyle. Alcohol use: may cause tachycardia, diaphoresis, and flushing. Avoid alcohol consumption.
Sun exposure: may increase risk of photosensitivity reaction. Avoid unprotected sun exposure.
EFFECTS ON DIAGNOSTIC TESTS
None reported.
CONTRAINDICATIONS
Contraindicated in patients hypersensitive to drug and in those with porphyria or hepatocellular failure. Also contraindicated in pregnant patients or women who intend to become pregnant during therapy.
SPECIAL CONSIDERATIONS
Use drug cautiously in penicillin-sensitive patients.
• Alert: Because of potential toxicity, drug is used only when topical treatment fails.
Laboratory tests are obtained to confirm diagnosis. Drug is continued until clinical and laboratory examinations confirm eradication.
Alert: Because griseofulvin ultramicrosize is dispersed in polyethylene glycol, it’s absorbed more rapidly and completely than microsize preparations and is effective at one-half to two-thirds the usual griseofulvin dose. Preparations are not interchangable.
Drug is administered after a high-fat meal to enhance absorption and minimize GI distress.
Hematologic, renal, and hepatic function need to be assessed periodically during prolonged therapy.
Discontinue drug in patients who experience agranulocytosis.
Effective treatment of tinea pedis may require concomitant use of a topical drug
Safety in children under age 2 hasn’t been established.
Patient teaching
Take drug after a high-fat meal.
Prolonged treatment may be needed to control infection and prevent relapse, even if symptoms abate in first few days of therapy.
Keep skin clean and dry and to maintain good hygiene.
Avoid intense sunlight. Unprotected sun exposure may cause photosensitivity reactions.
About the Author
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I Have Acute Intermittent porphyria Do you have it? Would like to talk to others with this disease?
Would like to talk to others with this disease. I know it is a rare disease but it is effecting my everyday life.
Robbie, if you live in So. California, there’s a good support group in this area. We meet twice a year and do our best to help each other feel less distant from other people. A rare disorder is not fun. I have VP and have experienced all kinds of mistreatment from MDs, etc. Nita
What is Porphyria?? (The Disease)
