Onset and Duration of Withdrawal Symptoms

Onset of alcohol withdrawal is usually between six and 24 hours after the last drink. In some people with severe alcohol dependence, withdrawal can occur when the blood alcohol level is decreasing, even if the patient is still intoxicated or has consumed alcohol recently; a significant proportion of people with alcohol dependence experience the onset of withdrawal symptoms before the blood alcohol level reaches zero. Patient care should not be decided on based upon blood alcohol level alone. Alcohol withdrawal rating scales can be used to assess the patient’s level of alcohol withdrawal symptoms. 

While for most people the alcohol withdrawal syndrome is short-lived and inconsequential, in others it increases in severity through the first 48 to 72 hours of abstinence. The patient becomes highly vulnerable to psychological and physiological stress during this time. Psychological symptoms of alcohol withdrawal, including dysphoria, sleep disturbance and anxiety, often persist for several weeks after drinking cessation. Other substance use, medical and psychiatric conditions can affect the onset, severity and duration of alcohol withdrawal. Use of benzodiazepines or other sedatives often delays the onset of withdrawal and diminishes its severity. It also provides guidance on prevention and treatment of Wernicke’s encephalopathy in these patients.