What are common side effects of Effexor XR?
Mild Effexor XR side effects include nausea, difficulty sleeping, weakness, fatigue, drowsiness, sweating, or constipation. If these symptoms persist, one must notify the physician. In rare cases, Effexor can cause severe depression, suicidal thoughts, anxiety, nervousness, tremors, decreased libido and headaches. If these side effects occur one should seek immediate medical attention. Effexor can rarely cause a syndrome called the serotonin syndrome which occurs when it is mixed with certain migraine medications (triptans). The syndrome presents with hallucinations, diarrhea, tremor, anxiety, inability to walk, slurred speech and fast heart rate. This is a medical emergency for which a physician must be seen immediately. Effexor can also induce an allergic reaction which may present with a skin rash, itching, dizziness or trouble breathing. In such cases, one should seek immediate medical attention.