TERCONAZOLE
Clinical safety rating: safe
Animal studies have demonstrated safety
Terconazole is a triazole antifungal agent that inhibits fungal cytochrome P450 14α-demethylase, thereby blocking the conversion of lanosterol to ergosterol, an essential component of the fungal cell membrane. This disrupts membrane integrity and function.
| Metabolism | Terconazole is not significantly absorbed systemically after intravaginal administration. Any absorbed drug is metabolized in the liver via oxidation and N-dealkylation, and excreted in urine and feces. |
| Excretion | Primarily hepatic metabolism with biliary excretion; approximately 60-80% of the dose is excreted in feces as metabolites, and about 20% in urine mostly as inactive metabolites. |
| Half-life | Terminal elimination half-life is approximately 25-37 hours, allowing once-daily dosing for vaginal infections. |
| Protein binding | Approximately 88-89% bound to plasma proteins, primarily albumin. |
| Volume of Distribution | Volume of distribution is not well characterized in humans but is estimated to be around 1.6 L/kg, indicating extensive tissue penetration. |
| Bioavailability | Vaginal administration: systemic bioavailability is low (approximately 5-16%) due to limited absorption; oral bioavailability not applicable as drug is not administered orally. |
| Onset of Action | For vaginal cream or suppository: clinical improvement begins within 24 hours of first dose; maximum effect by 4-7 days. |
| Duration of Action | Therapeutic concentrations persist in vaginal tissues for up to 72 hours after a single dose; standard course is 3-7 days for complete eradication. |
Intravaginal cream (0.4%, 0.8%): one applicatorful (approximately 5 g) intravaginally once daily at bedtime for 7 days; vaginal suppository (80 mg): one suppository intravaginally once daily at bedtime for 3 days.
| Dosage form | CREAM |
| Renal impairment | No dose adjustment required for renal impairment. |
| Liver impairment | No specific guidelines; use with caution in severe hepatic impairment due to limited data. |
| Pediatric use | Safety and efficacy not established in pediatric patients <18 years. |
| Geriatric use | No specific dose adjustment; use same as adult dosing. Consider potential for vaginal dryness or atrophy. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
No significant drug interactions For vaginal use only can cause vulvovaginal burning.
| Breastfeeding | Minimal systemic absorption after vaginal use; M/P ratio not established. It is not known if terconazole is excreted in human milk. Due to low systemic absorption, risk to nursing infant is likely low. Use with caution; consider alternate therapy if prolonged or recurrent use. |
| Teratogenic Risk | FDA Pregnancy Category C. No adequate and well-controlled studies in pregnant women. Systemic absorption after vaginal application is minimal (approximately 5%), thus fetal exposure is low. Animal studies at doses up to 20 mg/kg/day (5 times the human vaginal dose) showed no teratogenic effects, but embryotoxicity was observed at maternotoxic doses. Risk to fetus cannot be ruled out; use only if clearly needed. |
■ FDA Black Box Warning
None
| Common Effects | Vaginal burning |
| Serious Effects |
["Hypersensitivity to terconazole or any component of the formulation","Hypersensitivity to other azole antifungals"]
| Precautions | ["Use in patients hypersensitive to azole antifungals","If irritation or sensitization occurs, discontinue use","Safety in pregnancy (Category C): use only if clearly needed","Do not use during menstruation; complete full course of therapy"] |
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| Fetal Monitoring | No specific monitoring required beyond routine prenatal care. Monitor for local adverse effects (irritation, burning). If used systemically (unlikely), monitor hepatic function. |
| Fertility Effects | No reported effects on fertility in animal studies. No human data on fertility impact from intravaginal use. |