Half-lives of important psychiatric drugs

Cannabis. Plasma clearance is rapid (minutes), but this is largely by redistribution. Terminal t½ = 20/24 – 13/7. Dectectable in urine 3 to 30/7.

Amphetamines. Detectable in urine 2–4/7.

Cocaine. Detectable 2–4/7.

Ethanol is metabolised at about 1 unit/h (UK unit = 10 ml = 7.8 g EtOH).

Morphine terminal t½ = 2–4/24.

Heroin (Diamorphine) terminal t½ = 3/60.