Brand names: Amytal and Amytal Sodium, Soneryl, Prominal, Nembutal, Luminal, Tuinal

Street names: Angels (Amytal), Nembies (Nembutal), Chewies (Tuinal)

Street use: Barbiturates can be swallowed but more often heavy users dissolve the powders in water and inject.

Drug effect: Barbiturates are depressants or 'downers'. They work by depressing the activity of the entire nervous system. At low doses they decrease motor activity and produce sedation and drowsiness. Paradoxically they may produce excitement, elation and euphoria, slurred speech and general weariness. At high doses, barbiturates further decrease cognitive activity, distort judgement and provoke hypnosis. Higher doses produce anaesthesia.

Dependency: Develops very rapidly as the level of the drug increases.

Withdrawal: Symptoms appear within 24 hours of the last dose, peak about the second day and then fade over the next week. Symptoms include: restlessness, anxiety, and insomnia. Among heavy users there may be delirium and seizure. This is particularly likely to follow sudden withdrawal and so doses should be reduced gradually over time.

Long-term use: Can lead to chronic inebriation, aggressive behaviour, impaired judgement and severe insomnia.

Overdose risk: Although tolerance develops rapidly, the gap between a safe (for a heavy user) and lethal dose is very narrow and so accidental overdoses are very common. Large doses can lead to respiratory failure, coma and eventual death. Overdose risk increases if mixed with other drugs such as cocaine, alcohol and opiates.

Risk in pregnancy: Large doses of some barbiturates in pregnancy have been associated with congenital malformations.

Legal status: Barbiturates are a prescription only medicine and a Class B controlled drug. If prepared for injection, barbiturates become Class A drugs.

Class A – Maximum penalty

For possession: 7 years and/or an unlimited fine

For dealing: Life and/or unlimited fine

Class B – Maximum penalty

For possession: 5 years and/or unlimited fine

For dealing: 14 years and/or unlimited fine

SPECIAL NOTE: Seconal and Tuinal are dangerous drugs because of the risk of overdose, seizures following sudden withdrawal and hypothermia.