[Volatile anesthetics and tricyclic antidepressives. A case study]

Tricyclic antidepressants (TAD) are administered for therapy of nearly all types of depression. Interactions with anaesthetics are well known and are reported frequently in the literature. A case report about incidental findings from a series of experimental anaesthesias in healthy volunteers using different inhalation anaesthetics is presented enabling discussion of the problem of a possibly increased risk of anaesthesia in the presence of chronic TAD medication. 16 unpremedicated healthy subjects (mean age 27 +/- 4 y) received, at intervals of four weeks, inhalation anaesthesia by breathing spontaneously one of the volatile anaesthetics halothane, enflurane, or isoflurane in oxygen. The aim of the study was to investigate the influence of volatile anaesthetics on the human electroencephalogram. When evaluating the results an atypical increase of heart rate during anaesthesia was noticed in one subject. This tachycardia appeared during all three types of anaesthesia, all other observed parameters being normal. With the knowledge of these facts the volunteer was interviewed more thoroughly. He then admitted to have taken daily 125-175 mg of the TAD amitriptyline during the whole period of experiments (self-medication from lover's grief). We supposed therefore that the tachycardia during anaesthesia could be interpreted as an interaction between the TAD amitriptyline and the volatile anaesthetics halothane, enflurane, and isoflurane. After having discontinued TAD medication for some months, the volunteer, a medical student, repeated the experimental isoflurane anaesthesia with all other conditions identical. This time his heart rate did not differ from that of the other subjects.(ABSTRACT TRUNCATED AT 250 WORDS)