Indications
- Dermatophyte infections of the skin, scalp, and nails.
- Tinea pedis (moccasin type)/tinea manuum(adults): 750–1000 mg/day (microsize) or 500–750 mg/day (ultramicrosize) × 4 weeks.
- Tinea pedis (moccasin type)/tinea manuum(children):15–20 mg/kg/day (microsize suspension) × 4 weeks.
- Tinea unguium (adults):1–2 g/day (microsize) or 750 mg/day (ultramicrosize) until nails are normal.
- Tinea unguium (children) :20 mg/kg/day (microsize suspension) until nails are normal.
- Tinea corporis (extensive, adults) :500–1000 mg/day (microsize) or 375–500 mg/day (ultramicrosize) × 2–4 weeks.
- Tinea corporis (extensive, children):15–20 mg/kg/day (microsize suspension) × 2–4 weeks.
- Tinea capitis (adults):10–15 mg/kg/day (ultramicrosize; usually maximum 750 mg/day) ×6–8 weeks.
- Tinea capitis (children):20–25 mg/kg/day (microsize suspension) × 6–8 weeks.
- Tinea imbricata :500 mg twice daily for 4–6 weeks.
- Tinea barbae :Micronized or ultramicronized griseofulvin,500–1000 mg/day or 500–750 mg/day po,respectively, for 4–6 weeks.
- Majocchi granuloma.
others
- Lichen planus : 3 to 6 months.
- Erythema dyschromicum perstans.
- WELLS syndrome.
Follow Up Monitoring
With prolonged use :
- Complete blood count.
- Liver functions.
Side effects
- COMMON
- Urticaria.
- Nausea, headache, confusion, vomiting, diarrhea, flatulence, increased thirst.
- Candidiasis.
- Photosensitivity.
- Lupus-like reaction.
- Estrogenic effects.
- Paresthesias.
- Dizziness, fatigue, insomnia,proteinuria.
- RARE
- Fixed drug eruptions.
- Granulocytopenia.
- Hepatotoxicity.
- Neutropenia.
- Nephrotoxicity.
- Erythema multiforme.
- Angioedema.
- Mental confusion.
Contraindications
- Hypersensitivity to drug/class.
- Porphyria.
- Pregnancy.
- Penicillin allergy.
- Impaired liver function.
- Lupus erythematosus.
Mechanism of action
- Fungistatic and anti-inflammatory agent that deposits in the keratinocytes, which are gradually exfoliated and replaced by new, uninfected cells.
- It disrupts mitotic spindle by interacting with microtubules, thereby inhibiting mitosis in dermatophytes.
Interactions
- Decreased levels of: alfentanil, amiodarone, aprepitant, aripiprazole, bortezomib, bosentan, buprenorphine, benzodiazepines, carbamazepine, calcium channel blockers, clarithromycin, oral contraceptives, cyclosporin, delavirdine, disopyramide, efavirenz, erythromycins, fentanyl, geftinib, itraconazole, ketoconazole, levonorgestrel, paclitaxel, protease inhibitors, repaglinide, sirolimus, statins, tacrolimus, voriconazole, warfarin,salicylates, zonisamide.
- Decreased levels of griseofulvin: barbiturates.
- Disulfiram reaction: ethanol.
Pregnancy &Lactation
- Pregnancy category x.
- Rare cases of conjoined twins have been reported in women taking griseofulvin in the frst trimester of pregnancy.
- Excretion in milk is unknown, avoid use because of potential tumorigenicity.
Precautions
- Patients should avoid pregnancy for at least 1 month after discontinuing griseofulvin.
- Severe skin reactions (eg, Stevens-Johnson syndrome, toxic epidermal necrolysis) and erythema multiforme reported, some resulting in hospitalization or death; discontinue if severe skin reaction occurs.
- Elevations in AST, ALT, bilirubin, and jaundice reported, some resulting in hospitalization or death; discontinue if jaundice occurs.
- During prolonged griseofulvin therapy, periodic assessment of renal, hepatic, and hematopoietic functions should be performed.
- It may increase estrogen metabolizing liver enzymes, which may make oral contraceptives less effective or cause menstrual irregularities.
Drug Info
- The duration of therapy depends on the organism (e.g., T. tonsurans infections may require prolonged treatment schedules) but varies between 8 and 10 weeks.
- Shorter courses may lead to higher relapse rates.
- Griseofulvin is not effective in the treatment of pityriasis (tinea) versicolor, bacterial infections, candidiasis (moniliasis), or deep mycotic infections.
- Resistance to griseofulvin among dermatophytes is rare.
- Absorption of griseofulvin is improved when given with whole milk or ice cream.
- Drug particle size reduction through micronization and ultra-micronization has signifcantly enhanced oral absorption.