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. |
| Molecular Weight | 532.46 Da |
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 | Limited human data; animal studies show no teratogenicity. Use only if potential benefit outweighs risk. |
| 2nd trimester | No known fetal risk; minimal systemic absorption. Generally considered safe. |
| 3rd trimester | No known fetal risk; minimal systemic absorption. Generally considered safe. |
Clinical note
No significant drug interactions For vaginal use only can cause vulvovaginal burning.
| Placental transfer | Minimal due to low systemic absorption (3-16%) after vaginal application; significant transfer unlikely. |
| Breastfeeding | Minimal systemic absorption after vaginal use; unlikely to cause adverse effects in infant. Compatible with breastfeeding. |
| Lactation Rating |
■ FDA Black Box Warning
None
| Common Effects | Vaginal burning |
| Serious Effects |
Hypersensitivity to terconazole or any component of the formulation
| 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 |
| Food/Dietary | No significant food interactions. Terconazole is minimally absorbed systemically when used vaginally; therefore, dietary restrictions are not required. Alcohol does not interact with this medication. |
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| L1 (Safest) |
| 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. |
| 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. |
| Clinical Pearls | Terconazole is a topical antifungal indicated for vulvovaginal candidiasis. Available as 0.8% vaginal cream (3-day regimen) and 0.4% cream or 80 mg suppository (7-day regimen). For uncomplicated cases, shorter courses (3-day) are effective and improve adherence. Avoid use during menstruation; delay treatment until menses ends. Complete treatment even if symptoms resolve. Not for oral or ophthalmic use. May interact with latex condoms and diaphragms, potentially reducing contraceptive efficacy and increasing risk of breakage. Do not use concomitant vaginal douches or other products. Consider alternative therapy if no improvement in 3 days. Safety in pregnancy, terconazole is category C; use only if clearly needed. |
| Patient Advice | Use exactly as prescribed for the full treatment duration, even if symptoms improve. · Insert the cream or suppository high into the vagina at bedtime for best results. · Do not use tampons, douches, spermicides, or other vaginal products during treatment. · Avoid sexual intercourse during treatment; terconazole can weaken latex condoms and diaphragms. · Wash hands before and after application. Sanitary pads can be used to protect clothing. · Notify your healthcare provider if symptoms persist after 3 days or if you develop fever, chills, or abdominal pain. · If you are pregnant, think you may be pregnant, or are breastfeeding, consult your healthcare provider before use. |