[Safety and efficacy of ketamine for pain relief].

Intravenous ketamine treatment is frequently used for the management of chronic pain, especially in those patients who do not benefit from other therapies. In this commentary we discuss the efficacy of ketamine for relief of chronic pain and ketamine's safety profile. A review of the literature indicates that only a few studies show that intravenous ketamine has analgesic effects that persist beyond the infusion period, an effect that occurs in about two-thirds of patients. Ketamine has multiple safety issues, ranging from psychotomimetic and schizotypal symptoms, sympathetic stimulation, tachycardia and hypertension, and damage to the liver and the urogenital tract. Damage to the urogenital tract seems to be restricted to individuals who chronically abuse ketamine. We indicate the need for large randomized trials in which ketamine is compared with an 'active' placebo.