Barbiturates are medicines that act on the central nervous system (CNS). As a group, they are known as central nervous depressants or sedative-hypnotic drugs. They cause drowsiness and may control seizures (convulsions).

Barbiturates make people very relaxed, calm, and sleepy. These drugs are sometimes used to help patients relax before surgery. In the past, barbiturates have been used to treat nervousness and sleep problems. Today they have generally been replaced by other medicines for these purposes. Barbiturates may become habit-forming and should not be used to relieve everyday anxiety and tension or to treat sleeplessness over long periods.

Barbiturates are available only with a physician's prescription. The recommended dosage depends on the type of barbiturate and other factors such as the patient's age and the condition for which the medicine is being taken. Some commonly used barbiturates are phenobarbital (Barbita) and secobarbital (Seconal).

Barbiturates should always be taken...