indication

For the treatment of candidiasis (a yeast-like fungal infection) of the vulva and vagina.

pharmacology

Terconazole is a triazole antifungal agent available for intravaginal use. It is structurally related to imidazole-derivative antifungal agents, although terconazole and other triazoles have 3 nitrogens in the azole ring. By inhibiting the 14-alpha-demethylase (lanosterol 14-alpha-demethylase), Terconazole inhibits ergosterol synthesis. Depletion of ergosterol in fungal membrane disrupts the structure and many functions of fungal membrane leading to inhibition of fungal growth.

mechanism of action

Terconazole may exert its antifungal activity by disrupting normal fungal cell membrane permeability. Terconazole and other triazole antifungal agents inhibit cytochrome P450 14-alpha-demethylase in susceptible fungi, which leads to the accumulation of lanosterol and other methylated sterols and a decrease in ergosterol concentration. Depletion of ergosterol in the membrane disrupts the structure and function of the fungal cell leading to a decrease or inhibition of fungal growth.

toxicity

The oral LD₅₀ values were found to be 1741 and 849 mg/kg for the male and female in rat.

biotransformation

Systemically absorbed drug appears to be rapidly and extensively metabolized. Terconazole primarily undergoes oxidatative N- and O-dealkylation, dioxolane ring cleavage, and conjugation.

absorption

Following intravaginal administration of terconazole in humans, absorption ranged from 5-8% in three hysterectomized subjects and 12-16% in two non-hysterectomized subjects with tubal ligations

half life

6.9 hours (range 4.0-11.3)

route of elimination

Following oral (30 mg) administration of 14C-labelled terconazole, excretion of radioactivity was both by renal (32-56%) and fecal (47-52%) routes.