MONISTAT
Clinical safety rating: caution
Comprehensive clinical and safety monograph for MONISTAT (MONISTAT).
Miconazole, the active ingredient in MONISTAT, inhibits fungal CYP51 (lanosterol 14-alpha-demethylase), blocking ergosterol synthesis and disrupting fungal cell membrane integrity, leading to cell death.
| Metabolism | Hepatic metabolism via CYP3A4 isoenzyme with oxidation and O-dealkylation. |
| Excretion | Primarily fecal (approximately 90%) as unchanged drug; less than 2% renal elimination. |
| Half-life | Approximately 90-120 minutes; supports twice-daily local dosing. |
| Protein binding | Highly protein bound (>90%), primarily to albumin. |
| Volume of Distribution | 0.5-1.0 L/kg; indicates extensive tissue penetration after systemic absorption, though systemic levels are low with topical use. |
| Bioavailability | Intravaginal: <1% systemic absorption; topical: approximately 1-2%. |
| Onset of Action | Intravaginal: symptomatic relief within 24 hours; topical: itching relief within 24-72 hours. |
| Duration of Action | Intravaginal: 1-3 days depending on formulation; topical: 12-24 hours per application. |
Intravaginal: 200 mg suppository at bedtime for 3 days, or 100 mg suppository at bedtime for 7 days, or 2% cream 5 g intravaginally at bedtime for 7 days. Topical: Apply 2% cream twice daily for 2-4 weeks.
| Dosage form | INJECTABLE |
| Renal impairment | No dose adjustment required for renal impairment; miconazole is minimally absorbed systemically. |
| Liver impairment | No formal studies; use caution in severe hepatic impairment due to possible accumulation if systemic absorption occurs. |
| Pediatric use | Children ≥12 years: same as adult dosing. Children <12 years: not recommended or use under specialist guidance. |
| Geriatric use | No specific dose adjustment; same as adult dosing. Monitor for local irritation or sensitivity. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for MONISTAT (MONISTAT).
| Breastfeeding | Miconazole is excreted in breast milk in small amounts; M/P ratio not established. Intravaginal use results in negligible systemic levels. Considered compatible with breastfeeding, but monitor infant for local irritation. |
| Teratogenic Risk | Category C. No evidence of teratogenicity in animal studies; limited human data. Intravaginal absorption is minimal, systemic exposure low. Risk to fetus not ruled out; use only if clearly needed. |
| Fetal Monitoring |
■ FDA Black Box Warning
None
| Serious Effects |
Hypersensitivity to miconazole or any component; known hypersensitivity to other azole antifungals (cross-sensitivity).
| Precautions | May interact with warfarin, potentiating anticoagulant effect; hypersensitivity reactions including urticaria, pruritus, and angioedema; avoid contact with eyes; discontinue if irritation or sensitivity occurs; do not use during menstruation; for vaginal use only. |
Loading safety data…
| No specific maternal or fetal monitoring required beyond standard prenatal care. Monitor for signs of vaginal irritation or hypersensitivity. |
| Fertility Effects | No known effect on fertility in animal or human studies. Reversible suppression of spermatogenesis reported in animal models at high systemic doses, unlikely with intravaginal use. |