Not sure you're right about taking two or more of these can cause it. Two of the drugs affect serotonin, but only trazadone does this primarily. However, any of these drugs by themselves (not including melatonin, which is not a drug and is one of the safest supplements ever studied) could cause all of your side effects and the combination wouldn't be appealing to me. Flexeril does affect serotonin, but also other neurotransmitters, but it's also not supposed to be used for more than a couple of weeks for its approved use as it shows no benefit after that. That's assuming you're using it as a muscle relaxant. It's almost addictive and an abused drug, as it is calming. Depakote has enough side effects to fill an encyclopedia, and if you aren't psychotic or have epilepsy other drugs are much easier to take. You don't say why you're taking any of these meds, but they kind of work against one another. Gabapentin is kind of like setting up an artificial GABA system in your body for nerve pain, and is sometimes used in conjunction with an antidepressant for anxiety. Depakote is a major targeter of your actual GABA system. If you look at the side effect profile of flexeril, it can cause all of your symptoms. So can depakote. So an adderall, which is speed, completely seemingly contrary to all the relaxants and sleep aids you're taking. Again, you don't say why you're taking this stew. If you did have serotonin syndrome, I think you'd be suffering much more severe symptoms, and it is rare, and would be hard to get on what you're taking, but if you think you have it ER would be the place to go. I'm guessing it's the whole stew you're taking, or any one of them, that's causing it. If it's really bad, given the tachycardia can be dangerous and adderall and depakote and flexeril can all cause it, if it's bad, again, ER might be indeed called for. And a new doctor might be called for as well. So what are you taking this mess for?