Not applicable.
Non-clinical data reveal no special hazard for humans based on conventional studies of genotoxicity and carcinogenic potential.
When rats were treated orally with alprazolam for 2 years, a tendency for a dose related increase in the number of cataracts (females) and corneal vascularization (males) was observed. These lesions did not appear until after 11 months of treatment.
In reproductive toxicity studies administration of alprazolam in rats and rabbits is associated at very high doses with developmental delay and an increased incidence of fetal death and skeletal malformations. In fertility studies, treatment of male rats at high doses prior to mating resulted in a decrease in the percentage of dams conceiving.
Following oral administration, alprazolam is readily absorbed. The peak plasma concentration is reached about 1.5 to 2 hours after administration of Xanor given with or without water. When taken with water, mean Tmax occurs about 15 minutes earlier than when taken without water with no change in Cmax or AUC. Plasma levels are proportional to the dose given; over the dose range of 0.5 mg to 3.0 mg, peak levels of 8.0 to 37 ng/mL are observed. The elimination half-life of alprazolam is approximately 12.5 hours (range 7.9 - 19.2 hours) after administration of Xanor in healthy adults.
Food decreased the mean Cmax by about 25% and increased the mean Tmax by 2 hours from 2.2 hours to 4.4 hours after the ingestion of a high-fat meal. Food did not affect the extent of absorption (AUC) or the elimination half-life.
DistributionIn vitro, alprazolam is bound (80 percent) to human serum protein. Serum albumin accounts for the majority of the binding.
Metabolism/EliminationAlprazolam is extensively metabolized in humans, primarily by cytochrome P450 3A4 (CYP3A4), to two major metabolites in the plasma: 4-hydroxyalprazolam and α-hydroxyalprazolam. A benzophenone derived from alprazolam is also found in humans. Their half-lives appear to be similar to that of alprazolam. The plasma concentrations of 4-hydroxyalprazolam and α-hydroxyalprazolam relative to unchanged alprazolam concentration were always less than 4%. The reported relative potencies in benzodiazepine receptor binding experiments and in animal models of induced seizure inhibition are 0.20 and 0.66, respectively, for 4hydroxyalprazolam and α-hydroxyalprazolam. Such low concentrations and the lesser potencies of 4hydroxyalprazolam and α-hydroxyalprazolam suggest that they are unlikely to contribute much to the pharmacological effects of alprazolam. The benzophenone metabolite is essentially inactive.
Alprazolam and its metabolites are excreted primarily in the urine.
No special requirements for disposal.
