ESZOPICLONE
Clinical safety rating: safe
Animal studies have demonstrated safety
Non-benzodiazepine sedative-hypnotic that binds to GABA-A receptors at a site distinct from benzodiazepine binding site, enhancing GABAergic inhibition and increasing chloride ion conductance.
| Metabolism | Primarily hepatic via CYP3A4 and CYP2E1; metabolites include N-oxide (active) and N-desmethyl (inactive). |
| Excretion | Renal: 75% (as metabolites, primarily N-desmethyleszopiclone and eszopiclone-N-oxide); Fecal: approximately 10%; less than 10% excreted unchanged in urine. |
| Half-life | 6 hours (range 5-8 hours); at steady state in elderly or hepatic impairment, half-life may be prolonged to approximately 9 hours. |
| Protein binding | 52-59% bound to plasma proteins (primarily albumin). |
| Volume of Distribution | 1.1 L/kg (suggesting extravascular distribution and tissue binding). |
| Bioavailability | Oral: approximately 80% (due to first-pass metabolism, absolute bioavailability is 50-80% depending on formulation). |
| Onset of Action | Oral: 30 minutes (peak plasma concentration at 1 hour). |
| Duration of Action | Approximately 6-8 hours based on sleep maintenance effects; sedation may persist longer in some patients. |
| Molecular Weight | 388.83 |
1 mg, 2 mg, or 3 mg orally once daily immediately before bedtime; maximum dose 3 mg/day.
| Dosage form | TABLET |
| Renal impairment | No specific dosage adjustment required for mild to moderate renal impairment. For severe renal impairment (CrCl < 30 mL/min), initial dose should be 1 mg and use with caution. |
| Liver impairment | In Child-Pugh Class A or B, initial dose 1 mg; maximum dose 2 mg. Contraindicated in Child-Pugh Class C. |
| Pediatric use | Not approved for use in pediatric patients (safety and efficacy not established). |
| Geriatric use | Initial dose 1 mg orally once daily immediately before bedtime; maximum dose 2 mg/day due to increased sensitivity and risk of falls. |
| 1st trimester | Limited human data; animal studies show increased risk of cleft palate. Avoid use unless benefit outweighs risk. |
| 2nd trimester | No adequate studies; potential fetal sedation and respiratory depression. Use only if clearly needed. |
| 3rd trimester | Risk of neonatal respiratory depression, hypotonia, and withdrawal. Avoid use, especially near term. |
Clinical note
CNS depressants including alcohol increase sedation risk May cause complex sleep behaviors like sleep-driving.
| Placental transfer | Crosses placenta; detected in cord blood. |
| Breastfeeding | Eszopiclone excreted into breast milk in low amounts. Monitor infant for sedation and poor feeding. Use caution. |
| Lactation Rating |
■ FDA Black Box Warning
None (no FDA boxed warning)
| Common Effects | Unpleasant taste |
| Serious Effects |
Hypersensitivity to eszopiclone or any component of formulationHistory of complex sleep behaviors (e.g., sleep-driving) with eszopiclone
| Precautions | Central nervous system depressant effects (risk of impaired alertness and motor coordination), Complex sleep behaviors (sleep-driving, preparing/eating food, making phone calls), Anaphylaxis and angioedema (rare), Behavioral changes (somnambulism, hallucinations, aggression), Dependence and withdrawal (tolerance, addiction with abrupt discontinuation), Elderly patients (increased fall risk, cognitive impairment), Respiratory depression (caution in COPD, sleep apnea) |
| Food/Dietary | High-fat meals delay absorption and reduce peak concentration. Avoid grapefruit juice as it may increase systemic exposure via CYP3A4 inhibition. |
Loading safety data…
| L3 (Moderately Safe) |
| Teratogenic Risk | Eszopiclone is classified as FDA Pregnancy Category C. Limited human data; animal studies have shown adverse effects. In the first trimester, there is potential risk of major malformations, although data are insufficient to quantify. Second and third trimester exposure may be associated with decreased fetal growth and respiratory depression. Use only if benefit outweighs risk. |
| Fetal Monitoring | Monitor maternal blood pressure, heart rate, and sedation level. Fetal monitoring includes ultrasound for growth and amniotic fluid volume if used chronically. Neonates should be observed for respiratory depression, hypotonia, and withdrawal symptoms (irritability, tremors) after delivery. |
| Fertility Effects | No specific human data on fertility. Animal studies at high doses showed no significant adverse effects on fertility or reproductive performance. Theoretical concern for hormonal disruption due to CNS depressant effects, but not established. |
| Clinical Pearls | Avoid in patients with complex sleep behaviors (e.g., sleep-driving). Use lowest effective dose due to tolerance risk. Contraindicated in severe hepatic impairment. Dose reduction needed in elderly (start 1 mg). Not for chronic use >7-10 days. Avoid with other CNS depressants. |
| Patient Advice | Take immediately before bedtime with at least 7-8 hours of sleep remaining. · Do not take with or after a high-fat meal as it delays onset. · Avoid alcohol and other sedatives to prevent excessive sedation. · May cause next-day drowsiness; avoid driving or hazardous activities. · Report any unusual sleep behaviors like sleep-walking or sleep-driving immediately. · Do not suddenly stop after prolonged use; taper under medical supervision. |