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. |
| Molecular Weight | 308.77 |
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 | Alprazolam is generally contraindicated in the first trimester due to an increased risk of congenital malformations, particularly oral clefts, based on some epidemiological studies. Use only if clearly needed and no safer alternative exists. |
| 2nd trimester | May be used with caution in the second trimester if maternal benefit clearly outweighs fetal risk. Monitor for fetal growth and development. Avoid chronic use. |
| 3rd trimester | Use in the third trimester, especially near delivery, carries a high risk of neonatal withdrawal syndrome, floppy infant syndrome, and respiratory depression. Avoid use during late pregnancy and lactation. |
Clinical note
Comprehensive clinical and safety monograph for XANAX (XANAX).
| Placental transfer | Alprazolam readily crosses the placenta. Fetal serum levels approximate maternal levels. Transplacental passage is rapid and significant, with potential for fetal accumulation after long-term use. |
| Breastfeeding |
■ 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 |
Acute narrow-angle glaucomaConcurrent use with ketoconazole, itraconazole, or other potent CYP3A4 inhibitorsSevere respiratory insufficiency (e.g., chronic obstructive pulmonary disease with hypercapnia)Myasthenia gravisSleep apnea syndromeKnown hypersensitivity to benzodiazepines or any component of the formulation
| 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 |
| Food/Dietary | Grapefruit and grapefruit juice may increase serum concentrations of alprazolam; avoid concurrent use. Alcohol consumption should be avoided due to additive CNS depression. High-fat meals may delay absorption but do not significantly alter overall exposure. |
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| Alprazolam is excreted into breast milk in small amounts. Chronic administration may lead to accumulation in the nursing infant, causing sedation, poor feeding, and potential withdrawal upon weaning. Use in breastfeeding is generally not recommended; if essential, use the lowest effective dose for the shortest duration and monitor the infant for signs of sedation and respiratory depression. |
| Lactation Rating | L3 (Moderately Safe) - Use with caution; avoid if possible. |
| 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. |
| Fertility Effects | May impair fertility in males and females; reversible upon discontinuation. |
| Clinical Pearls | Avoid abrupt discontinuation due to risk of withdrawal seizures; taper dose by 0.5 mg every 3 days. Use with caution in elderly due to increased fall risk and cognitive impairment. Onset of action is rapid (15-30 minutes) making it suitable for panic attacks. Contraindicated in narrow-angle glaucoma and severe hepatic impairment. Monitor for respiratory depression when co-prescribed with opioids. |
| Patient Advice | Take exactly as prescribed; do not increase dose or frequency without consulting your doctor. · Do not stop taking suddenly as this can cause serious withdrawal symptoms including seizures; your doctor will wean you off gradually. · Avoid alcohol and other central nervous system depressants while taking this medication. · Do not drive or operate heavy machinery until you know how this medication affects you, as it may cause drowsiness or dizziness. · Inform your doctor if you are pregnant, planning to become pregnant, or breastfeeding. · Store at room temperature away from moisture and heat, out of reach of children. |