MICONAZOLE 3
Clinical safety rating: safe
Warfarin metabolism is inhibited increasing INR For topical use only not for ophthalmic use.
Miconazole inhibits fungal cytochrome P450 14α-demethylase (CYP51), thereby blocking the conversion of lanosterol to ergosterol, an essential component of the fungal cell membrane. This leads to increased membrane permeability, leakage of cellular contents, and fungal cell death.
| Metabolism | Miconazole is primarily metabolized in the liver via oxidative pathways, including CYP3A4-mediated metabolism. The main metabolites are inactive and excreted in feces and urine. Topical absorption is minimal (<1%), reducing systemic metabolism. |
| Excretion | Primarily hepatic metabolism; <1% excreted unchanged in urine; fecal elimination accounts for ~50% of metabolites. |
| Half-life | Terminal half-life is approximately 24 hours (range 20-30 hours) following topical vaginal application; prolonged in hepatic impairment. |
| Protein binding | ~90% bound primarily to albumin. |
| Volume of Distribution | 0.25-0.5 L/kg, indicating extensive tissue distribution. |
| Bioavailability | Systemic absorption from vaginal administration is minimal (~1.4%); oral bioavailability is low (~25-30%) due to extensive first-pass metabolism. |
| Onset of Action | Vaginal administration: clinical improvement within 1-3 days; maximal effect by 7 days. |
| Duration of Action | Single vaginal dose provides therapeutic levels for 3-5 days; typical treatment course is 3-7 days. |
For vaginal candidiasis: 200 mg (one suppository) intravaginally at bedtime for 3 consecutive days.
| Dosage form | CREAM |
| Renal impairment | No dosage adjustment required for renal impairment. |
| Liver impairment | Mild to moderate hepatic impairment (Child-Pugh A or B): no adjustment necessary. Severe hepatic impairment (Child-Pugh C): insufficient data; consider alternative therapy. |
| Pediatric use | Not recommended for pediatric patients; safety and efficacy not established. |
| Geriatric use | No specific dosage adjustment; use standard adult dosing with caution due to potential comorbidities. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Warfarin metabolism is inhibited increasing INR For topical use only not for ophthalmic use.
| FDA category | Human |
| Breastfeeding | Limited data on miconazole in breast milk. Systemic absorption after topical or intravaginal use is low. Milk-to-plasma ratio not established. Likely compatible with breastfeeding when used topically or intravaginally due to minimal absorption. |
| Teratogenic Risk | Miconazole is an azole antifungal. Based on limited human data, there is no evidence of increased risk of major birth defects with topical or intravaginal use. For oral or intravenous use, avoid in first trimester unless benefit outweighs risk. In animal studies, high systemic doses caused fetal toxicity. No known association with specific malformations. |
■ FDA Black Box Warning
None
| Common Effects | vaginal yeast infections |
| Serious Effects |
["Hypersensitivity to miconazole, any of its components, or other azole antifungals.","Not for ophthalmic or otic use (except specific ear drops).","Vaginal use contraindicated in known sensitivity to miconazole."]
| Precautions | ["For external use only; avoid contact with eyes, mouth, or vagina (unless using vaginal formulation).","May cause hypersensitivity reactions including contact dermatitis; discontinue if irritation or sensitization occurs.","Potential for cross-sensitivity with other azole antifungals.","Use with caution in patients with hepatic impairment due to potential systemic absorption.","Do not use occlusive dressings unless directed; may increase systemic absorption and adverse effects."] |
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| Fetal Monitoring | No specific monitoring required for topical or intravaginal use. For systemic use, monitor liver function tests (LFTs) and renal function. Assess for signs of hepatotoxicity or hypersensitivity. |
| Fertility Effects | No known adverse effects on fertility from standard topical or intravaginal doses. Systemic high doses may impair spermatogenesis or ovulation in animal studies at high doses, but data in humans are lacking for fertility. |