1. Clinical Overview
Alprazolam is a short-acting triazolobenzodiazepine derivative, primarily used as an anxiolytic and panicolytic agent. It is a potent central nervous system depressant that enhances the effect of the neurotransmitter gamma-aminobutyric acid (GABA) at the GABA-A receptor, resulting in sedative, hypnotic, anxiolytic, anticonvulsant, and muscle relaxant properties. The 0.25mg strength is the lowest available therapeutic dose, often used for initiation of therapy, in elderly patients, or for mild anxiety disorders in the Indian clinical setting.
| Onset | Duration | Bioavailability |
|---|---|---|
| Oral: 30 to 60 minutes. | Approximately 6 to 12 hours. | 80-90% following oral administration. |
2. Mechanism of Action
Alprazolam binds to a specific, high-affinity site (distinct from the GABA binding site) on the GABA-A receptor complex, which is a ligand-gated chloride channel. This binding allosterically enhances the affinity of GABA for its receptor. The increased GABA binding leads to an increased frequency of chloride channel opening, resulting in hyperpolarization of the neuronal membrane and reduced neuronal excitability.
3. Indications & Uses
- Generalized Anxiety Disorder (GAD)
- Panic Disorder with or without Agoraphobia
4. Dosage & Administration
Adult Dosage: Anxiety: Initial dose 0.25 mg to 0.5 mg two to three times daily. Maximum daily dose: 4 mg, in divided doses. Panic Disorder: Initial dose 0.5 mg three times daily; may be increased by no more than 1 mg daily every 3-4 days. Typical effective range: 5-6 mg/day; some may require up to 10 mg/day.
Administration: Administer orally with or without food. To be swallowed whole with water. For panic disorder, dosing should be divided equally throughout the day. Avoid grapefruit juice. Taper dose gradually to discontinue; do not stop abruptly.
5. Side Effects
Common side effects may include:
- Drowsiness/Sedation
- Lightheadedness/Dizziness
- Dry mouth
- Constipation
- Increased salivation
- Headache
- Blurred vision
- Fatigue
- Ataxia (especially in elderly)
- Slurred speech
6. Drug Interactions
| Drug | Effect | Severity |
|---|---|---|
| CYP3A4 Inhibitors (e.g., Ketoconazole, Itraconazole, Clarithromycin, Ritonavir) | Markedly increase alprazolam plasma levels, leading to profound sedation and respiratory depression. | Major |
| Other CNS Depressants (e.g., Alcohol, Opioids, Barbiturates, Other Benzodiazepines, Sedative Antihistamines) | Additive CNS depression, risk of profound sedation, respiratory depression, coma, and death. | Major |
| CYP3A4 Inducers (e.g., Carbamazepine, Phenytoin, Rifampicin, St. John's Wort) | Decrease alprazolam plasma levels, reducing therapeutic efficacy. | Moderate |
| Oral Contraceptives, Cimetidine | May decrease clearance of alprazolam, increasing its effects. | Moderate |
| Digoxin | Alprazolam may increase digoxin serum concentration, risk of toxicity. | Moderate |
| Levodopa | Alprazolam may decrease the therapeutic effects of levodopa. | Moderate |
7. Patient Counselling
- DO take the medication exactly as prescribed by your doctor.
- DO NOT increase the dose or frequency without consulting your doctor.
- DO NOT stop the medication abruptly. It must be tapered off under medical supervision.
- DO inform all your healthcare providers (doctors, dentists) that you are taking this medicine.
- DO NOT crush, break, or chew the tablet.
- DO keep all follow-up appointments with your doctor.
8. Toxicology & Storage
Overdose: Manifestations of overdose include somnolence, confusion, impaired coordination, diminished reflexes, coma, and death. Respiratory depression, hypotension, and bradycardia are seen, especially when combined with other CNS depressants.
Storage: Store at room temperature (15°C to 30°C), protected from light and moisture. Keep in the original container, tightly closed. Keep out of reach of children and pets. Do not flush unused medication. Dispose of as per local regulations or through a medicine take-back program.