Benzodiazepines are class of anti-anxiety agents which interfere with the inhibitory neurotransmitter gamma-aminobutyric acid (GABA). Their effects include anti-anxiety, sedation, sleep, muscle relaxation and anticonvulsant activity. Long-term benzodiazepine therapy can be associated with addiction and withdrawal symptoms. In toxicology, all unknown cause deaths are screened for benzodiazepines. The specimen screened is usually whole blood.