Hello doctor, Today my sister, who is 22 years old, started taking Venlafaxine 75 mg, but after a couple of hours she felt nauseated and started sweating and got red cheeks as well. Now I notice that her pupils are dilated, and she has severe muscle stiffness. She has cerebral palsy, sitting in a wheelchair, but now, suddenly, her left leg appears extremely stiff, she almost cannot bend it. Are these symptoms considered normal side effects? I am worried about isolated Venlafaxine-induced serotonin syndrome. She does not take any other medicine. Please guide me.
Hello. Sorry to know about your sister's symptoms. The symptoms you mentioned is for Serotonin syndrome which causes palpitations, muscle stiffness, hyperthermia, sweating, hyperactivity, and confusion. The mechanism is serotonin excess in the brain. It is one of the possible adverse effects of Venlafaxine (develop within hours). My advice is as follows: The symptoms will disappear within one day maximum. Does she take any other medications like anti-psychotics like Haloperidol? For more information consult an internal medicine physician online -->