TERAZOL 3
Clinical safety rating: caution
Comprehensive clinical and safety monograph for TERAZOL 3 (TERAZOL 3).
Terconazole is an azole 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 leads to fungal cell death.
| Metabolism | Systemic absorption after vaginal administration is minimal. Any absorbed terconazole is extensively metabolized in the liver via oxidation and N-dealkylation. The major metabolic pathway involves cytochrome P450 enzymes, though specific isozymes have not been clearly identified. |
| Excretion | Following intravaginal administration, terconazole is minimally absorbed (<5%) into systemic circulation. Absorbed drug is primarily metabolized in the liver and excreted via feces (approximately 50-60% as metabolites) and urine (approximately 20-30% as metabolites). Unabsorbed drug is excreted in feces. |
| Half-life | The terminal elimination half-life after intravaginal application is approximately 4-6 hours, reflecting local retention and slow systemic absorption of the small absorbed fraction. |
| Protein binding | Approximately 90% bound to plasma proteins, mainly albumin. |
| Volume of Distribution | Not well characterized due to minimal systemic absorption; estimated Vd is low (around 0.5-1 L/kg) based on parenteral data, but clinically irrelevant for intravaginal use as drug acts locally. |
| Bioavailability | Intravaginal: Minimal systemic bioavailability (<5%) due to low absorption; local bioavailability is high, achieving therapeutic vaginal concentrations. |
| Onset of Action | Intravaginal: Relief of symptoms (itching, discharge) typically begins within 24-48 hours after initiation of therapy; clinical cure may take 3-7 days. |
| Duration of Action | Intravaginal: Therapeutic concentrations persist locally for at least 72 hours after the last dose; a 3-day regimen provides coverage for 7 days. Systemic effects are negligible. |
One applicatorful (approximately 5 g of 0.8% terconazole vaginal cream) intravaginally once daily at bedtime for 3 consecutive days.
| Dosage form | CREAM |
| Renal impairment | No dose adjustment required for renal impairment. Terconazole is minimally absorbed systemically and undergoes hepatic metabolism; renal excretion of unchanged drug is negligible. |
| Liver impairment | No specific dose adjustment guidelines for hepatic impairment. Use caution in severe hepatic impairment due to potential drug accumulation, although systemic absorption is low. |
| Pediatric use | Safety and efficacy in pediatric patients below 12 years of age have not been established. For children 12 years and older, the adult dose of one applicatorful (5 g) intravaginally once daily at bedtime for 3 days is used. |
| Geriatric use | No specific dose adjustment required for elderly patients. Use same adult dosing regimen; consider potential for decreased vaginal mucosal integrity and concomitant medications. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for TERAZOL 3 (TERAZOL 3).
| Breastfeeding | Unknown if terconazole is excreted in human milk; M/P ratio not determined. Consider benefits of breastfeeding and importance of drug to mother; use caution. |
| Teratogenic Risk | Category C: No evidence of teratogenicity in animal studies; insufficient human data. Avoid use in first trimester unless benefit outweighs risk. Systemic absorption minimal; risk likely low. |
| Fetal Monitoring |
■ FDA Black Box Warning
None.
| Serious Effects |
["Hypersensitivity to terconazole or any component of the formulation.","Known hypersensitivity to other azole antifungal agents (cross-sensitivity may occur)."]
| Precautions | ["For intravaginal use only; not for ophthalmic or oral use.","If sensitization or irritation occurs, discontinue use.","Patients should discontinue use and consult a physician if symptoms persist (e.g., no improvement in 7 days) or if fever, chills, or flu-like symptoms develop.","Use with caution in patients with known hypersensitivity to other azole antifungal agents.","Pregnancy Category C: Animal studies have shown embryotoxicity at high doses; benefit should outweigh risk during pregnancy."] |
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| Monitor for local irritation or hypersensitivity; no specific fetal monitoring required due to minimal systemic absorption. |
| Fertility Effects | No known effect on fertility in animal studies; human data not available. |