Using Effexor XR with other drugs that make you drowsy can worsen this effect. Ask your doctor before using opioid medication, a sleeping pill, a muscle relaxer, or medicine for anxiety or seizures.
Tell your doctor about all your current medicines. Many drugs can interact with venlafaxine, especially:
any other antidepressant;
cimetidine;
tramadol;
St. John's wort, tryptophan (sometimes called L-tryptophan);
diet pills, weight loss medicine (such as phentermine);
a blood thinner - warfarin, Coumadin, Jantoven;
medicine to treat mood disorders, thought disorders, or mental illness - buspirone, lithium, and many others; or
migraine headache medicine - sumatriptan, zolmitriptan, and others.
This list is not complete and many other drugs may interact with venlafaxine. This includes prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible drug interactions are listed here.
 Effexor XR drug interactions (more detail)
