Ethchlorvynol has been used to treat insomnia, but has been largely superseded and is only offered where an intolerance or allergy to other drugs exists.

Along with expected sedative effects of relaxation and drowsiness, ethchlorvynol can cause skin rashes, faintness, restlessness and euphoria. Early adjustment side effects can include nausea and vomiting, numbness, blurred vision, stomach pains and temporary dizziness. An overdose is marked by confusion, fever, peripheral numbness and weakness, reduced coordination and muscle control, slurred speech, reduced heartbeat.

It is addictive and after prolonged use can cause withdrawal symptoms including convulsions, hallucinations, and memory loss. Due to these problems, it is unusual for ethchlorvynol to be prescribed for periods exceeding seven days. During the late 1970s, ethchlorvynol was sometimes over-prescribed causing a minor epidemic of persons who became addicted to this powerful drug. Occasional deaths would occur when addicted persons would try to inject the drug directly into a vein or an artery. Ethchlorvynol is not compatible with intravenous injection and serious injury or death can occur when it is used in this manner.^[3]