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. Misuse by
injection has been associated with serious acute toxicity. Reports describe severe noncardiogenic pulmonary oedema and
haemodynamic effects following
intravenous 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.
Overdose There is no specific antidote for ethchlorvynol overdose; management is primarily supportive and broadly parallels the approach used for other
sedative-hypnotic overdoses (including
barbiturate toxicity), with particular attention to airway, breathing, and circulation. 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.
Withdrawal Ethchlorvynol withdrawal following prolonged or high-dose use has been reported to produce a distinct
withdrawal syndrome, particularly after
abrupt discontinuation. Case reports describe symptoms including
confusion and perceptual disturbances, as well as severe presentations involving
psychosis,
delirium, and
seizures. 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 other
sedative-hypnotic drugs and may carry a risk of serious or potentially fatal complications without appropriate medical management.. Secondary pharmacology references have noted that chronic use of ethchlorvynol may lead to physical dependence, with withdrawal effects comparable to those of
barbiturate-class sedative-hypnotics, reinforcing the clinical significance of these reports ==Chemistry==