Pharmacological Classification and Properties
- Alprazolam is specifically a triazolo analog of the 1,4 benzodiazepine class of central nervous system-active compounds 1
- It has the chemical name 8-Chloro-1-methyl-6-phenyl-4H-s-triazolo[4,3-α]1, 4 benzodiazepine 1
- Alprazolam is classified as a triazolobenzodiazepine, which is a derivative of the benzodiazepine family 2, 3
Mechanism of Action
- Like other benzodiazepines, alprazolam activates γ-aminobutyric acid A (GABA) neuronal receptors in the brain 4
- Benzodiazepines produce anxiolytic, amnestic, sedating, hypnotic, and anticonvulsant effects, but have no analgesic activity 4
- Alprazolam's benzodiazepine receptor binding characteristics are qualitatively similar to those of other benzodiazepines 5
Regulatory Classification
- Alprazolam is a controlled substance under the Controlled Substances Act regulated by the Drug Enforcement Administration 1
- It is specifically assigned to Schedule IV of controlled substances 1
- This classification indicates its recognized potential for dependence and abuse, though lower than Schedule II or III substances 1, 6
Clinical Applications
- Benzodiazepines like alprazolam are used for anxiety disorders, insomnia, and acute delirium 7
- Alprazolam is specifically approved for the treatment of anxiety disorders and symptoms of anxiety, including anxiety associated with depression 2
- It is also used in the treatment of panic disorder, though this was not its initial approved indication 2, 8
- The Canadian Clinical Practice Guideline lists alprazolam as a second-line drug for social anxiety disorder 4
Pharmacokinetics
- Alprazolam achieves peak serum levels in 0.7 to 2.1 hours after administration 2
- It has a serum half-life of 12 to 15 hours 2
- The drug is metabolized primarily by hepatic microsomal oxidation, yielding alpha-hydroxy- and 4-hydroxy-alprazolam as principal initial metabolites 5
- Absolute bioavailability of oral alprazolam averages 80 to 100% 5
Safety Considerations
- Benzodiazepines can cause respiratory depression and systemic hypotension, especially when administered with other cardiopulmonary depressants like opioids 4
- Withdrawal symptoms can occur following discontinuation, which may include seizures, especially after rapid decrease or abrupt discontinuation 1
- Physical and psychological dependence can develop with prolonged use, particularly at doses greater than 4 mg/day 1
- Common side effects include drowsiness, headaches, lightheadedness, dry mouth, and depression 3
Important Clinical Distinctions
- Alprazolam is approximately ten times more potent than diazepam 3
- Compared to other benzodiazepines, alprazolam has a shorter half-life which may lead to more pronounced withdrawal symptoms 6
- Alprazolam may require special caution due to its reinforcing capabilities, relatively severe withdrawal syndrome, and potential for addiction 6