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| Pronunciation | /ˌɛθklɔːrˈvaɪnɒl/ ETH-klor-VY-nol |
| AHFS/Drugs.com | Micromedex Detailed Consumer Information |
| Routes of administration | Oral |
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| Pharmacokinetic data | |
| Protein binding | 35–50% |
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| ECHA InfoCard | 100.239.078 |
| Chemical and physical data | |
| Formula | C7H9ClO |
| Molar mass | 144.60 g·mol−1 |
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Ethchlorvynol is aGABA-ergichypnoticsedative medication first developed byPfizer in the 1950s.[4] In theUnited States, it was sold byAbbott Laboratories under the trade namePlacidyl.[2] Placidyl was available in 200 mg, 500 mg, and 750 mg strength gel filled capsules. While the 500 mg and 750 mg strength capsules were for use in reducing sleep latency, the 200 mg strength capsules were intended to be used to re-induce sleep in case of early awakening. Abbott discontinued production in 1999 due to problems of the widespread abuse ofminor tranquilizers, and non-barbiturate sedatives largely being replaced by thebenzodiazepine family (with drugs such as Librium and Valium);[5][2] by the end of 2001, ethchlorvynol reserves had dried up in the United States.
Theoretically, ethchlorvynol could be manufactured for sale in the United States by another pharmaceutical company (subject to FDA approval of such manufacture), though no pharmaceutical company has chosen to do so. Individuals with a valid prescription for the substance may legally transport a reasonable amount of ethchlorvynol with them into the United States. The availability of ethchlorvynol resembles similar barbiturate-like, GABA-ergic sedatives, such asglutethimide (Doriden, which ceased production in U.S. by 1993),ethinamate (Valmid), andmethyprylon (vended asNoludar,Noctan, andDimerin), which were voluntarilywithdrawn in favor of benzodiazepine hypnotics in 1965, and supplies widely eliminated by 1969. These are all controlled substances, but are not illegal.
Ethchlorvynol was indicated to treatinsomnia, and was widely prescribed in the 1960s and 1970s; prescriptions had fallen significantly by 1990, however, as other hypnotics that were considered safer and less dangerous in overdose became more common.
Ethchlorvynol is no longer prescribed in the United States due to unavailability, but is still available in some countries, and would still be considered legal to possess and use with a valid prescription.
Along with expected sedative effects (e.g. relaxation and drowsiness), reported adverse effects of ethchlorvynol include gastrointestinal upset (including nausea and vomiting), dizziness, blurred or altered vision, numbness or tingling, and unsteadiness or impaired coordination. Hypersensitivity reactions such as skin rash have also been reported.[6]
Misuse byinjection has been associated with serious acute toxicity. Reports describe severe noncardiogenic pulmonary oedema andhaemodynamic effects followingintravenous injection of ethchlorvynol (Placidyl), and public health sources have warned of cardiovascular or pulmonary injury arising from improper intravenous or intra-arterial injection of the drug.[7][8]
There is no specific antidote for ethchlorvynol overdose; management is primarily supportive and broadly parallels the approach used for othersedative-hypnotic overdoses (includingbarbiturate toxicity), with particular attention to airway, breathing, and circulation.[9][10] Reported features of ethchlorvynol overdose include confusion, slurred speech, unsteady gait or impaired coordination, slow or troubled breathing (respiratory depression), and slow heartbeat, along with severe poisoning that may progress to coma and death.[6] In severe cases, enhanced elimination has been reported (e.g.hemodialysis in a case of massive ingestion), though such interventions are case-dependent and adjunctive to supportive care.[11]
Ethchlorvynol withdrawal following prolonged or high-dose use has been reported to produce a distinctwithdrawal syndrome, particularly afterabrupt discontinuation. Case reports describe symptoms includingconfusion and perceptual disturbances, as well as severe presentations involvingpsychosis,delirium, andseizures. In some cases, withdrawal symptoms have been reported to occur after a delayed onset following discontinuation. Severe ethchlorvynol withdrawal has been described as resembling withdrawal syndromes associated with othersedative-hypnotic drugs and may carry a risk of serious or potentially fatal complications without appropriate medical management.[12][13][14]. Secondary pharmacology references have noted that chronic use of ethchlorvynol may lead to physical dependence, with withdrawal effects comparable to those ofbarbiturate-class sedative-hypnotics, reinforcing the clinical significance of these reports[15]
Ethchlorvynol is a member of the class of sedative-hypnotic carbinols, which includesmethylparafynol andtert-amyl alcohol. It is not abenzodiazepine,carbamate, orbarbiturate, and its molecular structure is considerably simpler. The systematic name of ethchlorvynol is usually given as ethyl 2-chlorovinyl ethynyl carbinol or 1-chloro-3-ethylpent-1-en-4-yn-3-ol.[citation needed] Its empirical formula is C7H9ClO.
Ethchlorvynol is synthesized by anethynylation reaction using lithiumacetylide and 1-chloro-1-penten-3-one inliquid ammonia, followed by acidicwork-up.[4][16]
Theanalogous compound consisting of acarbamate derived from thehydroxy group was investigated and was shown to have a slower onset, longer duration, and increased potency, but was not developed commercially.
