MYCELEX-G
Clinical safety rating: caution
Comprehensive clinical and safety monograph for MYCELEX-G (MYCELEX-G).
Clotrimazole, an imidazole antifungal, inhibits fungal cytochrome P450 14α-demethylase, disrupting ergosterol synthesis and increasing membrane permeability.
| Metabolism | Minimal systemic absorption; topically applied clotrimazole is largely metabolized in the liver to inactive metabolites. |
| Excretion | Primarily hepatic metabolism; about 80-90% of dose excreted as metabolites in feces via biliary excretion, less than 1% unchanged in urine. |
| Half-life | Biphasic: initial half-life ~30 minutes, terminal half-life ~30 hours; clinical significance: supports once-daily dosing for topical/vaginal formulations. |
| Protein binding | 90-95% bound to plasma proteins (primarily albumin). |
| Volume of Distribution | 0.08 L/kg in adults; reflects limited systemic distribution due to high protein binding and lipophilicity. |
| Bioavailability | Vaginal: negligible systemic bioavailability (absorbed <5% of dose); topical: similarly low systemic absorption. |
| Onset of Action | Vaginal: symptomatic relief begins within 1-3 days; systemic absorption minimal with local use. |
| Duration of Action | Vaginal administration: therapeutic concentrations persist for up to 72 hours; clinical use: single-dose or 3-7 day regimens. |
Clotrimazole 100 mg vaginal tablet inserted intravaginally once daily for 7 days or 200 mg once daily for 3 days; or 500 mg single dose. Also available as 1% vaginal cream, 1 applicatorful (5 g) intravaginally once daily for 7-14 days.
| Dosage form | TABLET |
| Renal impairment | No dosage adjustment required for renal impairment. |
| Liver impairment | No dosage adjustment required for hepatic impairment. |
| Pediatric use | Children ≥12 years: same as adult dosing. Children <12 years: safety and efficacy not established; use not recommended. |
| Geriatric use | Same as adult dosing; no specific geriatric adjustment required. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for MYCELEX-G (MYCELEX-G).
| Breastfeeding | No significant systemic absorption; therefore, it is considered compatible with breastfeeding. The M/P ratio is not applicable due to negligible plasma levels. |
| Teratogenic Risk | Clotrimazole is not absorbed systemically following vaginal administration. No teratogenic effects have been observed in animal studies and human data have not shown an increased risk of congenital anomalies. The benefits of treatment for symptomatic vaginitis generally outweigh any theoretical risk. |
| Fetal Monitoring |
■ FDA Black Box Warning
None
| Serious Effects |
Hypersensitivity to clotrimazole or any component of the formulation.
| Precautions | If irritation or sensitivity develops, discontinue use; not for ophthalmic or oral use; discontinue if signs of hypersensitivity occur. |
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| No specific monitoring required beyond standard pregnancy care. Monitor for persistent or recurrent symptoms. |
| Fertility Effects | No known effects on fertility. Clotrimazole does not impact reproductive function in animal studies. |