The pharmacokinetics and analgesic effect of i.v. ketamine in doses of 125 μg kg−1 and 250 μg kg−1 were determined in five healthy volunteers. Analgesia was measured with the submaximal effort tourniquet test. Both doses of ketamine prolonged the period of pain-free ischaemic exercise while the plasma ketamine concentration was greater than 100 ng ml−1. Ketamine was distributed rapidly (T½z=17 min). The elimination half-life was 186 min.
