What is the fine-grained topic of the following text: Using nalbuphine together with 5-hydroxytryptophan can increase the risk of a rare but serious condition called the serotonin syndrome, which may include symptoms such as confusion, hallucinations, seizures, extreme changes in blood pressure, increased heart rate, fever, excessive sweating, shivering or shaking, blurred vision, muscle spasm or stiffness, tremor, incoordination, stomach cramp, nausea, vomiting, and diarrhea. Only return the topic.
The risks of combining nalbuphine and 5-hydroxytryptophan