MYCELEX
Clinical safety rating: caution
Comprehensive clinical and safety monograph for MYCELEX (MYCELEX).
Clotrimazole, an imidazole antifungal, inhibits fungal cytochrome P450 14α-demethylase, thereby disrupting ergosterol biosynthesis and compromising fungal cell membrane integrity.
| Metabolism | Clotrimazole is extensively metabolized in the liver via cytochrome P450 enzymes, primarily CYP3A4, to inactive metabolites. |
| Excretion | Primarily hepatic metabolism; <1% excreted unchanged in urine; ~50% of dose excreted in feces as metabolites. |
| Half-life | Terminal elimination half-life is 20-50 hours (mean ~30 hours) in adults; prolonged in neonates (~40-80 hours) and in hepatic impairment. |
| Protein binding | 92-95% bound to plasma proteins, primarily albumin. |
| Volume of Distribution | 0.12-0.24 L/kg; indicates limited tissue distribution, primarily confined to extracellular fluid. |
| Bioavailability | Topical (vaginal): Minimal systemic absorption (<10%); oral troche: Negligible systemic absorption due to local action. |
| Onset of Action | Topical (vaginal cream/suppository): Symptomatic relief begins within 24-72 hours. Oral troche: Not applicable for systemic effect; local mucosal action onset within hours. |
| Duration of Action | Topical: Therapeutic effect persists for the duration of treatment (usually 3-7 days); single-dose vaginal tablet maintains therapeutic concentrations for up to 72 hours. |
| Molecular Weight | 344.4 |
For oropharyngeal candidiasis: Clotrimazole troche 10 mg dissolved slowly in mouth 5 times daily for 14 days. For vulvovaginal candidiasis: Clotrimazole vaginal tablet 500 mg single dose or 200 mg daily for 3 days or 100 mg daily for 7 days; 1% vaginal cream 5 g intravaginally daily for 7-14 days.
| Dosage form | Solution |
| Renal impairment | No dosage adjustment required for renal impairment. |
| Liver impairment | No specific dosage adjustment recommended; use with caution in severe hepatic impairment. |
| Pediatric use | For oropharyngeal candidiasis in children ≥3 years: Clotrimazole troche 10 mg dissolved slowly in mouth 5 times daily for 14 days. For vulvovaginal candidiasis in adolescents: same as adult dosing. Safety and efficacy in children <3 years not established. |
| Geriatric use | No specific dosage adjustment; use with caution due to potential for decreased salivary flow affecting troche dissolution. |
| 1st trimester | No evidence of fetal harm in animal studies; limited human data. Generally considered safe when used topically. |
| 2nd trimester | No known risks; topical use considered safe. |
| 3rd trimester | No known risks; topical use considered safe. |
Clinical note
Comprehensive clinical and safety monograph for MYCELEX (MYCELEX).
| Placental transfer | Minimal systemic absorption following topical use; negligible placental transfer expected. |
| Breastfeeding | Minimal systemic absorption after topical application; unlikely to be excreted into breast milk in clinically significant amounts. Compatible with breastfeeding. |
| Lactation Rating |
■ FDA Black Box Warning
None.
| Serious Effects |
Hypersensitivity to clotrimazole or any component
| Precautions | Hepatic impairment: monitor liver function; hypersensitivity reactions; for intravaginal use, discontinue if irritation or sensitization occurs; not for ophthalmic use. |
| Food/Dietary | No clinically significant food interactions for topical formulations. For oral troches, avoid consuming food or beverages immediately after administration to maximize mucosal contact. Grapefruit juice may theoretically increase systemic absorption if swallowed, but topical use negligible. |
| Clinical Pearls |
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| L1 (Safest) |
| Teratogenic Risk | FDA Pregnancy Category C. No adequate studies in pregnant women. In animal studies, no teratogenic effects observed at topical doses up to 100 mg/kg/day. Systemic absorption from topical application is minimal, but in first trimester, use only if clearly needed. In second and third trimesters, risk is low but avoid if possible. |
| Fetal Monitoring | No specific monitoring required for topical use. For systemic use, monitor liver function tests, renal function, and complete blood count due to potential hepatotoxicity and bone marrow suppression. |
| Fertility Effects | No known effects on fertility in humans. In animal studies, no impairment of fertility at doses up to 100 mg/kg/day. |
| Mycelex (clotrimazole) is a broad-spectrum azole antifungal used topically for mucocutaneous candidiasis. For vaginal candidiasis, consider single-dose regimens for uncomplicated cases; cure rates exceed 80%. Avoid occlusive dressings on skin lesions. For oral thrush in immunocompromised patients, troches are preferred over rinses for sustained contact. Caution in patients with hepatic impairment due to potential accumulation with systemic absorption. |
| Patient Advice | Use exactly as directed; complete full course even if symptoms improve. · For vaginal cream or suppositories, insert high into vagina at bedtime. · Do not use tampons, douches, or have intercourse during treatment. · Wash hands before and after application; avoid contact with eyes. · Notify if symptoms persist after 7 days or if fever, chills, or foul odor develop. · For oral troches, allow to dissolve slowly in mouth; do not chew or swallow whole. · Keep medication away from children; store at room temperature away from moisture. |