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. |
| Molecular Weight | 344.84 |
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 | Topical clotrimazole is generally considered safe in the first trimester. Systemic absorption is minimal (<1%). Although data are limited, no increased risk of fetal abnormalities has been reported in large observational studies. |
| 2nd trimester | Use is considered safe in the second trimester. Minimal systemic absorption reduces fetal exposure. Standard topical dosing is appropriate. |
| 3rd trimester | Use is considered safe in the third trimester. No known fetal or neonatal adverse effects. Continue standard topical dosing. |
Clinical note
Comprehensive clinical and safety monograph for MYCELEX-G (MYCELEX-G).
| Placental transfer | Minimal. Due to low systemic absorption after topical application, placental transfer is negligible. Direct data on human placental transfer are lacking, but low plasma concentrations suggest clinically insignificant transfer. |
| Breastfeeding | Clotrimazole is poorly absorbed through skin and mucous membranes, with negligible systemic levels (<1%). Topical use during breastfeeding is considered safe; avoid application to the breast or nipple area to minimize infant oral exposure. |
■ 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. |
| Food/Dietary | No significant food interactions. Avoid alcohol if experiencing side effects like nausea. |
| Clinical Pearls | Mycelex-G (clotrimazole vaginal cream/tablets) is effective for vulvovaginal candidiasis. Advise patients to complete full course even if symptoms resolve. Monitor for allergic reactions. Avoid use during menstruation for cream; tablets can be used anytime. Consider drug interactions with anticoagulants (rare). |
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| Lactation Rating | L1 (Safe) |
| 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 | 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. |
| Patient Advice | Use the medication as directed for the full duration, even if symptoms improve. · Avoid sexual intercourse during treatment as it may reduce efficacy and cause irritation. · Do not use tampons, douches, or other vaginal products unless advised by your healthcare provider. · If you are using the vaginal cream, apply at bedtime to minimize leakage. · Inform your doctor if symptoms persist after treatment completion. |