Alprazolam
Generic Name: Alprazolam
Sold under the trade name Xanax
Uses
Alprazolam, sold under the trade name Xanax, among others, is a short-acting benzodiazepine. It is most commonly used in short term management of anxiety disorders, specifically panic disorder or generalized anxiety disorder (GAD). Other uses include the treatment of chemotherapy-induced nausea, together with other treatments. GAD improvement occurs generally within a week. Alprazolam is available by mouth.
Side Effects
Common side effects include sleepiness, depression, headaches, feeling tired, dry mouth, and memory problems. Some of the sedation and tiredness may improve within a few days. Withdrawal or rebound symptoms may occur if use is suddenly decreased. Other rare risks include suicide, possibly due to loss of inhibition.
Pharmacodynamics
As a benzodiazepine, alprazolam produces a variety of therapeutic and adverse effects by binding to the GABAA benzodiazepine receptor site and modulating its function; GABA receptors are the most prolific inhibitory receptor within the brain. The GABA chemical and receptor system mediates inhibitory or calming effects of alprazolam on the nervous system. Binding of alprazolam to the GABAA receptor, a chloride ion channel, enhances the effects of GABA, a neurotransmitter. When GABA binds the GABAA receptor the channel opens and chloride enters the cell which makes it more resistant to depolarisation. Therefore, alprazolam has a depressant effect on synaptic transmission to reduce anxiety.
Pharmacokinetics
Alprazolam is taken orally, and is absorbed well – 80% of alprazolam binds to proteins in the serum (the majority binding to albumin). The concentration of alprazolam peaks after one to two hours.
Alprazolam is metabolized in the liver, mostly by the enzyme cytochrome P450 3A4 (CYP3A4). Two major metabolites are produced: 4-hydroxyalprazolam and α-hydroxyalprazolam, as well as an inactive benzophenone. The low concentrations and low potencies of 4-hydroxyalprazolam and α-hydroxyalprazolam indicate that they have little to no contribution to the effects of alprazolam.
The metabolites, as well as some unmetabolized alprazolam, are filtered out by the kidneys and are excreted in the urine