Serotonin syndrome is thought to result from the over-stimulation of the 5-HT1A and
5-HT2A receptors and possibly other serotonin receptors in the
central nervous system.
It can, exceptionally, occur with the use of one drug, but much more usually it
develops when two or more drugs with serotonergic actions are given together. The
characteristic
symptoms fall into three main areas, namely altered mental status
(agitation, confusion, mania), autonomic dysfunction (diaphoresis, diarrhoea, fever,
shivering) and neuromuscular abnormalities (hyperreflexia, incoordination, myoclo-
nus, tremor).
Serotonin syndrome usually resolves within about 24 hours if the
offending drugs are withdrawn and supportive measures given. Most patients recover
uneventfully, but there have been a few fatalities. Many drugs have serotonergic
actions, but the advice on concurrent use of these drugs varies greatly between
manufacturers. The
SSRIs are amongst the most commonly implicated drugs, and the
concurrent use of serotonergic drugs with
SSRIs is generally cautioned. The most
practical approach therefore seems to be to monitor for potential
symptoms, and to
seek medical advice should they occur.