XANAX
Clinical safety rating: caution
Comprehensive clinical and safety monograph for XANAX (XANAX).
Alprazolam is a benzodiazepine that binds to the gamma-aminobutyric acid (GABA)-A receptor at the α1, α2, α3, and α5 subunits, enhancing the effect of GABA by increasing chloride ion conductance, leading to neuronal hyperpolarization and inhibition of neurotransmission.
| Metabolism | Hepatic metabolism primarily via CYP3A4 to active metabolites (e.g., α-hydroxyalprazolam). |
| Excretion | Renal: ~80% (mainly as glucuronide metabolites, <20% unchanged). Fecal: <7%. |
| Half-life | Terminal elimination half-life: 11.2 hours (range 6.3–26.9 hours). With repeated dosing, half-life may prolong slightly; clinical context: allows once-daily dosing for most patients. |
| Protein binding | 80% bound to albumin. |
| Volume of Distribution | Vd: 0.71–1.26 L/kg (mean ~0.9 L/kg). Indicates moderate tissue distribution with accumulation in CNS. |
| Bioavailability | Oral: 80–90% (immediate-release). Rectal: ~90%. Intramuscular: ~90%. |
| Onset of Action | Oral: 30–60 minutes (immediate-release). Sublingual: 5–15 minutes. Intramuscular: 15–30 minutes. |
| Duration of Action | Duration: 4–6 hours (immediate-release), up to 12 hours (extended-release). Clinical note: sedative effects may persist beyond anxiolytic duration. |
Initial: 0.25-0.5 mg orally 3 times daily; maximum: 4 mg/day in divided doses. For panic disorder: 0.5-1 mg at bedtime or 0.5 mg 3 times daily; titrate as needed up to 10 mg/day.
| Dosage form | TABLET |
| Renal impairment | No specific GFR-based guidelines; use caution in severe renal impairment (CrCl <30 mL/min). Consider dose reduction or increased dosing interval due to prolonged half-life. Avoid in dialysis patients due to lack of dosing studies. |
| Liver impairment | Child-Pugh Class A: No adjustment recommended. Child-Pugh Class B: Reduce dose by 50% of normal starting dose. Child-Pugh Class C: Avoid use (no established safety). |
| Pediatric use | Not approved for use in patients <18 years (safety and efficacy not established). Off-label for panic disorder in adolescents: starting dose 0.25-0.5 mg daily; titrate slowly based on response. |
| Geriatric use | Initiate at 0.25 mg orally 2-3 times daily (lower starting dose). Titrate cautiously due to increased sensitivity and risk of falls/cognitive impairment. Maximum recommended dose: 2 mg/day in divided doses. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for XANAX (XANAX).
| Breastfeeding | Xanax is excreted in breast milk; M/P ratio 0.36. Avoid due to potential sedative effects on the infant. |
| Teratogenic Risk | First trimester: Increased risk of oral clefts; second and third trimesters: Risk of floppy infant syndrome, withdrawal, and CNS depressant effects. |
| Fetal Monitoring | Monitor for sedation, respiratory depression, and withdrawal in neonate; fetal growth and development with ultrasound. |
■ FDA Black Box Warning
Concomitant use of benzodiazepines and opioids may result in profound sedation, respiratory depression, coma, and death. Reserve concomitant prescribing for patients for whom alternative treatment options are inadequate.
| Serious Effects |
["Hypersensitivity to alprazolam or other benzodiazepines","Acute narrow-angle glaucoma","Concurrent use of ketoconazole or itraconazole (strong CYP3A4 inhibitors)","Pregnancy (especially first trimester) and breastfeeding (risk of neonatal sedation/withdrawal)"]
| Precautions | ["Dependence and withdrawal reactions (including seizures) with abrupt discontinuation","Risk of abuse, misuse, and addiction","Concomitant use with CNS depressants increases risk of respiratory depression","Suicidal thinking and behavior","Activation of mania/hypomania in patients with bipolar disorder","Use in patients with narrow-angle glaucoma","Elderly and debilitated patients: increased sensitivity and risk of falls"] |
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| Fertility Effects | May impair fertility in males and females; reversible upon discontinuation. |