Hi, concomitant use of Meridia (sibutramine) with other serotonin reuptake inhibitors or other agents
possessing serotonergic activity such as Effexor (venlafaxine) may potentiate the risk of serotonin syndrome,
which is a rare but serious and potentially fatal condition thought to result from hyperstimulation of
brainstem 5-HT1A and 2A receptors. Symptoms of the serotonin syndrome may include mental status changes such
as irritability, altered consciousness, confusion, hallucinations, and coma; autonomic dysfunction such as
tachycardia, hyperthermia, diaphoresis, shivering, blood pressure lability, and mydriasis (dilatation of
pupils); neuromuscular abnormalities such as hyperreflexia, myoclonus, tremor, rigidity, and ataxia; and
gastrointestinal symptoms such as abdominal cramping, nausea, vomiting, and diarrhea. At least 14 days should
elapse between discontinuation of other serotonergic agents and initiation of treatment with sibutramine.
In case these two medications have to be prescribed, patients should be closely monitored for symptoms of the
serotonin syndrome during treatment. I hope this information is of help to you.
