griseofulvin (Fulvicin, Grifulvin, Grisactin)
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Introduction
Tradenames: Fulvicin, Grifulvin, Grisactin.
Indications
- dermatophytoses infections of the skin, hair & nails
- has also used in the management of gout
Dosage
Adults:
Children:
- microsize: 10-15 mg/kg/day divided QD, BID or TID
- ultramicrosize: (< 2 months of age) 5.5-7.3 mg/kg/day
Duration of therapy:
- Tinea corporis: 2-4 weeks
- Tinea capitis: 4-6 weeks or longer
- Tinea pedis: 4-8 weeks
- Tinea unguium: 4-6 months
Tabs: (Fulvicin, Grisactin): 125, 250, 500 mg.
Suspension: (Grifulvin): 125 mg/5 mL.
Pharmacokinetics
- absorption is poor, increased when taken with high-fat meal
- concentrated in skin, hair, liver & muscle
- 1/2life is 9-24 hours
- metabolized in liver
- eliminated in feces & perspiration
elimination via skin
elimination via liver
1/2life = 9-24 hours
Monitor
- liver function tests periodically[4]
Adverse effects
- common (> 10%)
- less common (1-10%)
- oral thrush, vomiting, epigastric distress, diarrhea, headache, fatigue, dizziness, insomnia, confusion
- uncommon (< 1%)
- proteinuria, nephrosis, leukopenia, hepatotoxicity, GI bleeding, menstrual irregularites, angioneurotic edema
- other[3]
Drug interactions
- phenobarbital
- griseofulvin induces cyt P450 3A4
- may diminish levels of drugs metabolized by cyt P450 3A4 (warfarin effects may be diminished)
- alcohol in combination leads to flushing
- oral contraceptives may have diminished effectiveness
Mechanism of action
- fungistatic
- disrupts fungus mitotic spindle apparatus, arresting cells in metaphase
- deposited in keratin
- therapy must be continued to allowed complete cell replacement with non-infected tissue
More general terms
Additional terms
References
- ↑ The Pharmacological Basis of Therapeutics, 9th ed. Gilman et al, eds. Permagon Press/McGraw Hill, 1996
- ↑ Kaiser Permanente Northern California Regional Drug Formulary, 1998
- ↑ 3.0 3.1 Drug Information & Medication Formulary, Veterans Affairs, Central California Health Care System, 1st ed., Ravnan et al eds, 1998
- ↑ 4.0 4.1 Prescriber's Letter 17(7): 2010 Recommended Lab Monitoring for Common Medications Liver Function Test Scheduling Detail-Document#: http://prescribersletter.com/(5bhgn1a4ni4cyp2tvybwfh55)/pl/ArticleDD.aspx?li=1&st=1&cs=&s=PRL&pt=3&fpt=25&dd=260704&pb=PRL (subscription needed) http://www.prescribersletter.com
- ↑ 5.0 5.1 Deprecated Reference