Pharmacology Xanax
Pharmacology Report: Xanax aka Alprazolam
The drug Xanax is used to treat various anxiety disorders. The drug is considered a benzodiazepine (BZD) which are known as benzos or downers. BZD are psychoactive and Xanax speed of onset is rather quick making it a useful drug for someone having an acute panic or anxiety attack.
The drug works in a mysterious way and not all is known how exactly the operations take place. What is known is that the CNS agents of the 1, 4 benzodiazepine class "presumably" exert their effect by binding at receptors scattered about the central nervous system. This information is presumed, and once again, it is not fully known. Pfizer, the manufacturer of the drug clearly and explicitly states that "their exact mechanism of action is unknown. Clinically, all benzodiazepines cause a dose-related central nervous system depressant activity varying from mild impairment of task performance to hypnosis."
The drug is readily absorbed and peaking on the drug occurs in one to two hours. Alprazolam is extensively metabolized in humans, primarily by cytochrome P450 3A4 (CYP3A4), to two major metabolites in the plasma: 4-hydroxyalprazolam and ?-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 ?-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 4-hydroxyalprazolam and ?-hydroxyalprazolam. Such low concentrations and the lesser potencies of 4-hydroxyalprazolam and ?-hydroxyalprazolam suggest that they are unlikely to contribute much to the pharmacological effects of alprazolam. The benzophenone metabolite is essentially inactive. This medicine does not need to be taken with food since it is designed to treat acute panic attacks.
References
Evans, R.L., & Cardoni, A.A. (1981). Alprazolam (Xanax®, the Upjohn Company). Annals of Pharmacotherapy, 15(9), 633-638.
Glue, P., Fang, A., Gandelman, K., & Klee, B. (2006). Pharmacokinetics of an extended release formulation of alprazolam (Xanax XR) in healthy normal adolescent and adult volunteers. American journal of therapeutics, 13(5), 418-422.
