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griseofulvin (Fulvicin, Grifulvin, Grisactin)

Tradenames: Fulvicin, Grifulvin, Grisactin. Indications: - dermatophytoses infections of the skin, hair & nails - Trichophyton - Microsporum - Epidermophyton - Tinea barbae, Tinea capitis, Tinea corporis, Tinea pedis, Tinea cruris [5] - has also used in the management of gout Dosage: Adults: 1) microsize: 500-1000 mg/day divided QD or BID 2) ultramicrosize: a) 330-375 mg/day divided QD, BID or TID b) up to 750 mg/day may be necessary for Tinea unguium Children: 1) microsize: 10-15 mg/kg/day divided QD, BID or TID 2) ultramicrosize: (< 2 months of age) 5.5-7.3 mg/kg/day Duration of therapy: 1) Tinea corporis: 2-4 weeks 2) Tinea capitis: 4-6 weeks or longer 3) Tinea pedis: 4-8 weeks 4) Tinea unguium: 4-6 months Tabs: (Fulvicin, Grisactin): 125, 250, 500 mg. Suspension: (Grifulvin): 125 mg/5 mL. Pharmacokinetics: 1) absorption is poor, increased when taken with high-fat meal 2) concentrated in skin, hair, liver & muscle 3) 1/2life is 9-24 hours 4) metabolized in liver 5) eliminated in feces & perspiration Monitor: - liver function tests periodically [4] Adverse effects: 1) common (> 10%) - skin rash - urticaria 2) less common (1-10%) - oral thrush, vomiting, epigastric distress, diarrhea, headache, fatigue, dizziness, insomnia, confusion 3) uncommon (< 1%) - proteinuria, nephrosis, leukopenia, hepatotoxicity, GI bleeding, menstrual irregularites, angioneurotic edema 4) other [3] - nausea/vomiting - photosensitivity - peripheral neuritis Drug interactions: 1) phenobarbital 2) griseofulvin induces cyt P450 3A4 -> may diminish levels of drugs metabolized by cyt P450 3A4 (warfarin effects may be diminished) 3) alcohol in combination leads to flushing 4) oral contraceptives may have diminished effectiveness Mechanism of action: 1) fungistatic 2) disrupts fungus mitotic spindle apparatus, arresting cells in metaphase 3) deposited in keratin 4) therapy must be continued to allowed complete cell replacement with non-infected tissue

Interactions

drug interactions

Related

cytochrome P450 3A4 (cytochrome P450 C3, nifedipine oxidase, P450-PCN1, NF-25, CYP3A4)

General

antifungal agent

Properties

MISC-INFO: elimination route SKIN LIVER 1/2life 9-24 HOURS pregnancy-category C safety in lactation ?

Database Correlations

PUBCHEM correlations

References

  1. The Pharmacological Basis of Therapeutics, 9th ed. Gilman et al, eds. Permagon Press/McGraw Hill, 1996
  2. Kaiser Permanente Northern California Regional Drug Formulary, 1998
  3. Drug Information & Medication Formulary, Veterans Affairs, Central California Health Care System, 1st ed., Ravnan et al eds, 1998
  4. Prescriber's Letter 17(7): 2010 Recommended Lab Monitoring for Common Medications Liver Function Test Scheduling Detail-Document#: 260704 (subscription needed) http://www.prescribersletter.com
  5. Deprecated Reference