Venlafaxine is used to treat depression. It is also used to treat general anxiety disorder, social anxiety disorder, and panic disorder. Venlafaxine belongs to a group of medicines known as serotonin and norepinephrine reuptake inhibitors (SNRI). These medicines are thought to work by increasing the activity of a chemical called serotonin in the brain.

This medicine is available only with your doctor's prescription.

Take this medicine only as directed by your doctor to benefit your condition as much as possible. Do not take more of it, do not take it more often, and do not take it for a longer time than your doctor ordered.

This medicine should come with a Medication Guide. It is very important that you read and understand this information. Be sure to ask your doctor about anything you do not understand.

Take the extended-release capsule or tablet with food either in the morning or evening at about the same time each day. If your doctor tells you to take the medicine a certain way, take it exactly as directed.

Swallow the extended-release capsule whole with fluid. Do not crush, chew, divide, or place the capsule in a liquid.

If you are unable to swallow the extended-release capsule, open it and pour the medicine on a spoonful of applesauce. Swallow the mixture of applesauce and medicine right away without chewing. Drink a glass of water so all of the medicine is swallowed.

Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur:

More common

Lack or loss of strength

severe headache

sweating

Less common

Blurred vision

chest pain

fast or irregular heartbeat

mood or mental changes

ringing or buzzing in the ears

suicidal thoughts

Rare

Actions that are out of control

convulsions

high fever

irritability

itching or skin rash

lightheadedness or fainting, especially when getting up suddenly from a sitting or lying position

menstrual changes

nervousness

problems with urinating or holding urine

severe muscle stiffness

talking, feeling, and acting with excitement that you cannot control

trouble breathing

unusually pale skin

Incidence not known

Agitation

bloody, black, or tarry stools

bloody stool or urine

dark urine

decreased frequency or amount of urine

diarrhea

drowsiness

fever

general feeling of tiredness or weakness

headache

increased thirst

light-colored stools

muscle cramps, spasms, or pain

nausea or vomiting

nosebleeds

overactive reflexes

poor coordination

red or purple spots on the skin

restlessness

shivering

stomach pain on the upper right side

swelling of the face, lower legs, ankles, hands, or fingers

trembling or shaking that is hard to control

twitching

unusual bruising

unusual tiredness or weakness

vomiting of blood or material that looks like coffee grounds

yellow eyes or skin

Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

More common

Abnormal dreams

chills

constipation

decrease in sexual desire or ability

diarrhea

dry mouth

heartburn

increased sweating

loss of appetite

nausea

stomach pain or gas

stuffy or runny nose

tingling, burning, or prickly sensations

trouble sleeping

vomiting

weight loss

Less common

Change in taste

muscle tension

yawning

Incidence not known

Night sweats

Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.

Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.

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.