Are sweating, dilated pupil and muscle stiffness side effects of Venlafaxine?

Question

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.

Answer 1

Hello,

Welcome to icliniq.com.

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:

Stop the medication.
One tablet of Xanax (Alprazolam) 25 mg once. Consult your specialist doctor, discuss with him or her and take medications with their consent.
Cooling shower.

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.

Answer 2

Hi,

Welcome back to icliniq.com.

The first 24 hours have passed so the critical period is over. Serotonin syndrome is life threatening if there is disorientation and muscle rigidity. The critical period is 24 hours. How are the other symptoms like sweating, palpitations and dilated pupils? Have they improved? If yes, then it is a good sign. Stop any antidepressant for the moment. Give her Xanax before bedtime. Is she improving generally?

For more information consult an internal medicine physician online.