venlafaxine

Venlafaxine is an antidepressant in a group of drugs called selective serotonin and norepinephrine reuptake inhibitors (SSNRIs). Venlafaxine affects chemicals in the brain that may become unbalanced and cause depression.

Venlafaxine is used to treat major depressive disorder, anxiety, and panic disorder.

Important information

You should not take venlafaxine if you have uncontrolled narrow-angle glaucoma, or if you are being treated with methylene blue injection.

Do not use venlafaxine if you have taken an MAO inhibitor in the past 14 days. A dangerous drug interaction could occur. MAO inhibitors include isocarboxazid, linezolid, phenelzine, rasagiline, selegiline, and tranylcypromine. After you stop taking venlafaxine, you must wait at least 7 days before you start taking an MAOI.

Some young people have thoughts about suicide when first taking an antidepressant. Your doctor will need to check your progress at regular visits while you are using this medicine. Your family or other caregivers should also be alert to changes in your mood or symptoms.

Report any new or worsening symptoms to your doctor, such as: mood or behavior changes, anxiety, panic attacks, trouble sleeping, or if you feel impulsive, irritable, agitated, hostile, aggressive, restless, hyperactive (mentally or physically), more depressed, or have thoughts about suicide or hurting yourself.

Do not give this medicine to anyone younger than 18 years old without the advice of a doctor. Venlafaxine is not approved for use in children.

Before taking this medicine

You should not take this medicine if you are allergic to venlafaxine or desvenlafaxine (Pristiq), or:

• if you have uncontrolled narrow-angle glaucoma; or

• if you are being treated with methylene blue injection.

Do not use venlafaxine if you have taken an MAO inhibitor in the past 14 days. A dangerous drug interaction could occur. MAO inhibitors include isocarboxazid, linezolid, phenelzine, rasagiline, selegiline, and tranylcypromine. After you stop taking venlafaxine, you must wait at least 7 days before you start taking an MAOI.

To make sure venlafaxine is safe for you, tell your doctor if you have:

• bipolar disorder (manic depression);

• cirrhosis or other liver disease;

• kidney disease;

• heart disease, high blood pressure, high cholesterol;

• diabetes;

• narrow-angle glaucoma;

• a thyroid disorder;

• a history of seizures;

• a bleeding or blood clotting disorder;

• low levels of sodium in your blood; or

• if you are switching to venlafaxine from another antidepressant.

Some young people have thoughts about suicide when first taking an antidepressant. Your doctor will need to check your progress at regular visits while you are using venlafaxine. Your family or other caregivers should also be alert to changes in your mood or symptoms.

FDA pregnancy category C. Taking an SSRI antidepressant during pregnancy may cause serious lung problems or other complications in the baby. However, you may have a relapse of depression if you stop taking your antidepressant. Tell your doctor right away if you become pregnant while taking venlafaxine. Do not start or stop taking this medicine during pregnancy without your doctor"s advice.

See also: Pregnancy and breastfeeding warnings (in more detail)

Venlafaxine can pass into breast milk and may harm a nursing baby. You should not breast-feed while using this medicine.

Do not give this medicine to anyone younger than 18 years old without the advice of a doctor. Venlafaxine is not approved for use in children.

How should I take venlafaxine?

Take venlafaxine exactly as prescribed by your doctor. Follow all directions on your prescription label. Do not take this medicine in larger or smaller amounts or for longer than recommended.

Venlafaxine should be taken with food. Try to take venlafaxine at the same time each day.

Swallow the controlled-release capsule (Effexor XR) whole, without crushing or chewing. To make the medication easier to swallow, you may open the capsule and sprinkle the medicine into a small amount of applesauce. Swallow all of the mixture without chewing, and do not save any for later use.

Your blood pressure will need to be checked often.

It may take 4 weeks before your symptoms improve. Keep using the medication as directed and tell your doctor if your symptoms do not improve.

You should not stop using venlafaxine suddenly. Follow your doctor"s instructions about tapering your dose.

This medicine can cause you to have a false positive drug screening test. If you provide a urine sample for drug screening, tell the laboratory staff that you are taking venlafaxine.

Store at room temperature away from moisture and heat.

What happens if I miss a dose?

Take the missed dose as soon as you remember. Skip the missed dose if it is almost time for your next scheduled dose. Do not take extra medicine to make up the missed dose.

What happens if I overdose?

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

What should I avoid while taking venlafaxine?

Ask your doctor before taking a nonsteroidal anti-inflammatory drug (NSAID) for pain, arthritis, fever, or swelling. This includes aspirin, ibuprofen (Advil, Motrin), naproxen (Aleve), celecoxib (Celebrex), diclofenac, indomethacin, meloxicam, and others. Using an NSAID with venlafaxine may cause you to bruise or bleed easily.

Avoid drinking alcohol, which can increase some of the side effects of venlafaxine.

Venlafaxine may impair your thinking or reactions. Be careful if you drive or do anything that requires you to be alert.

Venlafaxine side effects

Get emergency medical help if you have any of these signs of an allergic reaction to venlafaxine: skin rash or hives; difficulty breathing; swelling of your face, lips, tongue, or throat.

Report any new or worsening symptoms to your doctor, such as: mood or behavior changes, anxiety, panic attacks, trouble sleeping, or if you feel impulsive, irritable, agitated, hostile, aggressive, restless, hyperactive (mentally or physically), more depressed, or have thoughts about suicide or hurting yourself.

Call your doctor at once if you have:

• blurred vision, tunnel vision, eye pain or swelling, or seeing halos around lights;

• easy bruising;

• cough, chest tightness, trouble breathing;

• seizure (convulsions);

• high levels of serotonin in the body - agitation, hallucinations, fever, fast heart rate, overactive reflexes, nausea, vomiting, diarrhea, loss of coordination, fainting;

• low levels of sodium in the body - headache, confusion, slurred speech, severe weakness, vomiting, loss of coordination, feeling unsteady; or

• severe nervous system reaction - very stiff (rigid) muscles, high fever, sweating, confusion, fast or uneven heartbeats, tremors, feeling like you might pass out.

Common venlafaxine side effects may include:

• vision changes;

• nausea, vomiting, diarrhea;

• changes in appetite or weight;

• dry mouth, yawning;

• dizziness, headache, anxiety, feeling nervous;

• fast heartbeats, tremors or shaking;

• sleep problems (insomnia), strange dreams, tired feeling;

• increased sweating; or

• decreased sex drive, impotence, or difficulty having an orgasm.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

See also: Side effects (in more detail)

Venlafaxine dosing information

Usual Adult Dose for Depression:

Immediate release:
Initial dose: 37.5 mg orally twice a day or 25 mg orally 3 times a day
Maintenance dose: May increase in daily increments of up to 75 mg at intervals of no less than 4 days
Maximum dose: (moderately depressed outpatients): 225 mg/day
Maximum dose (severely depressed inpatients): 375 mg/day
Daily dosage may be divided in 2 or 3 doses/day

Extended release:
Initial dose: 75 mg orally once daily
Maintenance dose: May increase in daily increments of up to 75 mg at intervals of no less than 4 days
Maximum dose (moderately depressed outpatients): 225 mg/day
Maximum dose (severely depressed inpatients): 375 mg/day

Usual Adult Dose for Anxiety:

For generalized anxiety disorder or social anxiety disorder:
Extended release:
Initial dose: 75 mg orally once daily
Maintenance dose: May increase in daily increments of 75 mg at intervals of no less than 4 days
Maximum dose: 225 mg/day

Usual Adult Dose for Panic Disorder:

Extended-release:
Initial dose: 37.5 mg once a day
Maintenance dose: May increase dose in daily increments of 75 mg at intervals of no less than 7 days
Maximum dose: 225 mg/day

What other drugs will affect venlafaxine?

Taking this medicine with other drugs that make you sleepy can worsen this effect. Ask your doctor before taking venlafaxine with a sleeping pill, narcotic pain medicine, muscle relaxer, or medicine for anxiety, depression, or seizures.

Many drugs can interact with venlafaxine. Not all possible interactions are listed here. Tell your doctor about all your medications and any you start or stop using during treatment with venlafaxine, especially:

• any other antidepressant;

• cimetidine;

• St. John"s wort;

• tramadol;

• tryptophan (sometimes called L-tryptophan);

• 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 can interact with venlafaxine. This includes prescription and over-the-counter medicines, vitamins, and herbal products. Give a list of all your medicines to any healthcare provider who treats you.