ESTAZOLAM
Clinical safety rating: avoid
Positive evidence of fetus risks but benefits may outweigh risks in some cases
Benzodiazepine that binds to GABA-A receptors at the alpha-1 subunit, enhancing the effect of GABA by increasing chloride ion conductance, leading to neuronal hyperpolarization and CNS depression.
| Metabolism | Primarily hepatic via CYP3A4; active metabolite (hydroxyestazolam) with half-life ~19 hours; excreted renally. |
| Excretion | Renal: ~90% as metabolites, <1% unchanged. Fecal: small amount, ~10%. |
| Half-life | Terminal elimination half-life: 10-24 hours (mean ~17 hours); prolonged in elderly and hepatic impairment. |
| Protein binding | ~93% bound to albumin. |
| Volume of Distribution | 0.8-1.3 L/kg; reflects moderate tissue distribution. |
| Bioavailability | Oral: ~70-90% (extensive first-pass metabolism). |
| Onset of Action | Oral: 30-60 minutes; IV: not applicable. |
| Duration of Action | 6-8 hours; clinical effect may persist longer due to active metabolites. |
| Molecular Weight | 294.74 |
1-2 mg orally at bedtime.
| Dosage form | TABLET |
| Renal impairment | No dose adjustment required for GFR ≥ 30 mL/min. For GFR < 30 mL/min, use with caution and consider dose reduction due to potential accumulation of active metabolites. |
| Liver impairment | Child-Pugh Class A: No adjustment necessary. Child-Pugh Class B: Reduce dose by 50% (e.g., 1 mg maximum). Child-Pugh Class C: Avoid use. |
| Pediatric use | Not recommended for use in pediatric patients under 18 years of age due to lack of safety and efficacy data. |
| Geriatric use | Initial dose: 0.5 mg orally at bedtime, with maximum dose of 1 mg due to increased sensitivity and risk of falls and cognitive impairment. |
| 1st trimester | Avoid; possible increased risk of congenital malformations (cleft palate, cardiac defects) with first-trimester exposure. |
| 2nd trimester | Use only if benefit outweighs risk; associated with floppy infant syndrome, withdrawal symptoms. |
| 3rd trimester | Avoid; risk of neonatal respiratory depression, hypotonia, withdrawal, and floppy infant syndrome. |
Clinical note
CNS depressants including alcohol and opioids increase sedation risk Abrupt discontinuation can cause withdrawal symptoms.
| Placental transfer | Estazolam crosses the placenta with measurable fetal serum levels; rapid equilibration occurs between maternal and fetal circulation. |
| Breastfeeding | Estazolam is excreted into breast milk in small amounts; potential for infant sedation, lethargy, and weight loss. Monitor infant for signs of sedation and poor feeding. Avoid if possible, especially with prolonged use or high doses; consider alternative agents. |
■ 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. Limit dosages and durations to the minimum required.
| Common Effects | Sedation |
| Serious Effects |
History of hypersensitivity to estazolam or other benzodiazepinesPreexisting central nervous system depressionNarrow-angle glaucomaSevere respiratory insufficiency or sleep apnea syndrome
| Precautions | Risk of dependence and withdrawal reactions; avoid abrupt discontinuation., CNS depressant effects; caution with other CNS depressants., Respiratory depression risk, especially in patients with COPD or sleep apnea., Elderly patients: increased sensitivity and risk of falls., May cause anterograde amnesia, paranoia, and depression., Potential for abuse and misuse. |
| Food/Dietary |
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| Lactation Rating | L3 (Moderately Safe) – use with caution, especially with chronic use or high doses. |
| Teratogenic Risk | Pregnancy Category X. First trimester: increased risk of congenital malformations, particularly cleft lip/palate. Second and third trimesters: fetal benzodiazepine exposure associated with floppy infant syndrome, neonatal withdrawal (irritability, tremors, hypertonia), and respiratory depression. Use contraindicated in pregnancy. |
| Fetal Monitoring | Monitor maternal respiratory status, sedation level, and abuse potential. In pregnancy, fetal ultrasound for anomalies and neonatal monitoring for withdrawal signs and respiratory depression if inadvertent exposure occurs. |
| Fertility Effects | No direct evidence of impaired fertility. Chronic use may affect menstrual regularity and libido, potentially impacting fertility. |
| Avoid alcohol consumption - additive CNS depression and sedation. Grapefruit juice may increase estazolam levels via CYP3A4 inhibition; avoid concurrent use. No other specific food restrictions. |
| Clinical Pearls | Estazolam is a triazolobenzodiazepine with intermediate onset and duration, useful for sleep-onset and sleep-maintenance insomnia. Dose reduction is essential in elderly patients due to increased sensitivity and risk of falls. Avoid concurrent use with other CNS depressants (including alcohol) due to additive sedation. Monitor for tolerance, dependence, and withdrawal symptoms; limit use to short-term (2-4 weeks). Estazolam has no active metabolites, reducing accumulation risk in hepatic impairment. Contraindicated in narrow-angle glaucoma, severe respiratory insufficiency, and myasthenia gravis. |
| Patient Advice | Take estazolam exactly as prescribed, usually once at bedtime; do not increase dose or frequency without consulting your doctor. · Do not drink alcohol or use other sedative medications while taking this drug, as it can cause severe drowsiness, respiratory depression, and increased fall risk. · Avoid driving or operating heavy machinery until you know how estazolam affects you, as it may cause drowsiness, dizziness, or impaired coordination. · Do not stop taking estazolam abruptly; taper dose under medical supervision to avoid withdrawal symptoms (anxiety, agitation, seizures). · Inform your doctor if you are pregnant, planning to become pregnant, or breastfeeding; use effective contraception. · Report any new or worsening depression, abnormal thoughts, or unusual behavior immediately. · Store at room temperature away from moisture and heat; keep out of reach of children. |