If you will be taking this medicine for a long time, it is very important that your doctor check you at regular visits. This will allow your doctor to see if the medicine is working properly and to decide if you should continue to take it.
Do not take venlafaxine with a monoamine oxidase (MAO) inhibitor (eg, isocarboxazid (Marplan®), phenelzine (Nardil®)], selegiline (Eldepryl®), tranylcypromine (Parnate®)). Do not start taking venlafaxine during the 2 weeks after you stop a MAO inhibitor and wait 1 week after stopping venlafaxine before you start taking a MAO inhibitor. If you take them together or do not wait the proper amount of time, you may develop confusion, agitation, restlessness, stomach or intestinal symptoms, a sudden high body temperature, an extremely high blood pressure, or severe convulsions.
Venlafaxine may cause a serious condition called serotonin syndrome if taken together with certain medicines. Do not use venlafaxine with buspirone (Buspar®), fentanyl (Abstral®, Duragesic®), linezolid (Zyvox®), lithium (Eskalith®, Lithobid®), methylene blue injection, tryptophan, St. John's wort, amphetamines, or some pain or migraine medicines (eg, rizatriptan, sumatriptan, tramadol, Frova®, Imitrex®, Maxalt®, Relpax®, Ultram®, Zomig®). Check with your doctor first before taking any other medicines with venlafaxine.
For some children, teenagers, and young adults, this medicine can increase thoughts of suicide. Tell your doctor right away if you start to feel more depressed and have thoughts about hurting yourself. Report any unusual thoughts or behaviors that trouble you, especially if they are new or get worse quickly. Make sure the doctor knows if you have trouble sleeping, get upset easily, have a big increase in energy, or start to act reckless. Also tell the doctor if you have sudden or strong feelings, such as feeling nervous, angry, restless, violent, or scared. Let the doctor know if you or anyone in your family has bipolar disorder (manic-depressive) or has tried to commit suicide.
Do not stop taking this medicine without checking first with your doctor. Your doctor may want you to gradually reduce the amount you are taking before stopping it completely. This will decrease the chance of side effects, such as agitation, confusion, headache, irritability, numbness or tingling feeling, restlessness, trouble sleeping, or unusual drowsiness or weakness.
This medicine may cause hyponatremia (low sodium in the blood). This is more common in elderly patients, those who take diuretic medicines, or those who have a low amount of fluid in the body due to severe diarrhea or vomiting. Check with your doctor right away if you have a headache, trouble concentrating, memory problems, confusion, weakness, or feel unsteady when standing.
Venlafaxine may increase your risk for bleeding problems. Make sure your doctor knows if you are also using other medicines that thin the blood, such as aspirin, NSAID pain or arthritis medicines (eg, diclofenac, ibuprofen, naproxen, Advil®, Aleve®, Celebrex®, Voltaren®), or warfarin (Coumadin®, Jantoven®).
Tell your doctor right away if you are having chest discomfort, a cough, or trouble breathing with this medicine. These might be symptoms of a serious lung problem.
Venlafaxine may cause some people to become drowsy or have blurred vision. Make sure you know how you react to this medicine before you drive, use machines, or do anything else that could be dangerous if you are not alert or able to see clearly. It is best to avoid alcohol with venlafaxine.
Before you have any medical tests, tell the medical doctor in charge that you are taking this medicine. The results of some tests may be affected by this medicine.
Do not take other medicines unless they have been discussed with your doctor. This includes prescription or nonprescription (over-the-counter [OTC]) medicines and herbal (eg, St. John's wort) or vitamin supplements.