Drug Interactions between fenfluramine and tryptophan

GENERALLY AVOID: Concomitant use of agents with serotonergic activity such as serotonin reuptake inhibitors and tryptophan 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 5-HT2A 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; neuromuscular abnormalities such as hyperreflexia, myoclonus, tremor, rigidity, and ataxia; and gastrointestinal symptoms such as abdominal cramping, nausea, vomiting, and diarrhea.

MANAGEMENT: In general, the concomitant use of tryptophan and agents with serotonergic activity such as serotonin reuptake inhibitors should be avoided. If concomitant use is considered clinically necessary, caution and close monitoring for signs and symptoms of serotonin syndrome is recommended, particularly at treatment initiation and during any dosage increases. Patients should be instructed to seek immediate medical attention if they develop any signs or symptoms of serotonin syndrome. The product labeling for each serotonergic medication as well as any relevant guidelines should also be consulted for specific recommendations.