[Long-term antidepressive medication-- an increased anesthetic risk?]

Antidepressants inhibit the re-uptake of norepinephrine at the monoaminergic synapse from the synaptic fissure, leading in this way to an increased sensitivity to catecholamines. In addition, antidepressants have alpha1-, H1- and H2-receptor blocking effects and also anticholinergic effects; the tricyclic antidepressants in particular are known for these properties. A few animal experiments and some case reports indicate that a long-term treatment with these substances can lead to intra-operative blood pressure fluctuations, tachycardia and arrhythmias. Therefore a number of authors recommend that antidepressants be withdrawn 3 days before a planned operation. In view of the pharmacokinetics of these substances and the long-term adapting processes at the monoaminergic synapse this period is certainly too short to achieve complete loss of effectiveness. Other authors think preoperative withdrawal is not indicated if there is careful intraoperative monitoring. We agree with the latter opinion. Inhalation anesthesia with isoflurane or enflurane should be preferred. The muscle relaxant pancuronium should not be used, and exogenous intake of catecholamines should be avoided. Opiates seem to have a positive effect on cardiac stability. Benzodiazepines show the least interactions with antidepressants and are therefore recommended for premedication. In the postoperative period the possibility of an anticholinergic syndrome has to be considered.