ETHCHLORVYNOL
Clinical safety rating: caution
Comprehensive clinical and safety monograph for ETHCHLORVYNOL (ETHCHLORVYNOL).
Ethchlorvynol is a sedative-hypnotic with central nervous system depressant effects. Its exact mechanism is unknown, but it may potentiate GABA activity or depress neuronal excitability.
| Metabolism | Hepatic metabolism, primarily via glucuronidation; active metabolite is unknown. |
| Excretion | Renal: <1% unchanged; Hepatic metabolism to inactive conjugates; Fecal: minimal. Approximately 90% of a dose is excreted in urine as glucuronide conjugates within 24 hours. |
| Half-life | 10-25 minutes (initial rapid distribution phase); terminal elimination half-life approximately 4-6 hours in adults (prolonged in liver disease due to reduced clearance). |
| Protein binding | Approximately 35-40% bound to plasma proteins (albumin). |
| Volume of Distribution | 1.7-2.5 L/kg (large Vd indicates extensive tissue distribution, particularly to adipose tissue). |
| Bioavailability | Oral: approximately 70-80% due to extensive first-pass hepatic metabolism. |
| Onset of Action | Oral: 15-30 minutes (hypnotic effect); Intravenous: within 5 minutes. |
| Duration of Action | Oral: 3-5 hours (hypnotic effect); shorter duration at higher doses due to rapid redistribution. Accumulation may occur with repeated dosing, prolonging CNS depression. |
500 mg to 1 g orally at bedtime as needed for insomnia.
| Dosage form | CAPSULE |
| Renal impairment | No specific dosage adjustments are established; use with caution in severe renal impairment (GFR <30 mL/min) due to potential for accumulation and increased CNS effects. |
| Liver impairment | Contraindicated in hepatic impairment; avoid use in Child-Pugh class B or C cirrhosis due to risk of hepatic encephalopathy and altered metabolism. |
| Pediatric use | Safety and efficacy not established in pediatric patients; not recommended for use in children. |
| Geriatric use | Initial dose: 500 mg orally at bedtime; titrate cautiously due to increased sensitivity, risk of falls, cognitive impairment, and prolonged sedation. Avoid chronic use. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for ETHCHLORVYNOL (ETHCHLORVYNOL).
| Breastfeeding | No data on excretion in human breast milk; M/P ratio unknown. Consider risk of infant sedation and withdrawal; use only if benefit outweighs risk, alternative preferred. |
| Teratogenic Risk | First trimester: Limited data; animal studies show increased risk of fetal resorptions and anomalies at high doses; human data insufficient to determine risk. Second and third trimesters: Potential for neonatal withdrawal syndrome if used chronically near term; respiratory depression and hypotonia in neonates with high maternal doses. Controlled studies in pregnant women not available. |
■ FDA Black Box Warning
None.
| Serious Effects |
Hypersensitivity to ethchlorvynol, porphyria, and patients with a history of addiction to sedative-hypnotics.
| Precautions | May cause dependence and withdrawal symptoms. Avoid abrupt discontinuation. CNS depressant effects may be additive with alcohol or other depressants. Caution in patients with hepatic impairment, respiratory depression, or history of substance abuse. |
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| Fetal Monitoring | Monitor maternal vital signs, sedation level, and respiratory status. Fetal: Assess growth via ultrasound with prolonged use; monitor for neonatal withdrawal after delivery. |
| Fertility Effects | No human data on fertility effects; animal studies report decreased fertility at high doses, likely due to CNS depression and hormonal disruption. |