Zalcitabine is well absorbed following oral administration. Food in the GI tract may decrease the extent of absorption. Peak plasma concentrations in adults are attained in 0.5-2 hours. It is not known whether the drug is distributed in milk. The drug is not metabolized substantially in the liver.
Zalcitabine is eliminated principally in urine.
In patients with impaired renal functions, zalcitabine plasma concentrations may be increased and the half-life prolonged. Current recommendations generally advise a three-drug combination including a protease inhibitor. Concomitant use of zalcitabine and zidovudine against HIV appears to be synergistic. In vitro data suggests that ribavirin may antagonize the antiretroviral activity of zalcitabine, therefore concomitant use requires caution. Zalcitabine,at currently recommended dosages, appears generally to be well tolerated.