Venlafaxine belongs to the class of antidepressant medications known as selective serotonin and norepinephrine reuptake inhibitors (SSNRIs). It is used for the treatment of depression. It works on the central nervous system (CNS) to elevate mood in people with depression. Venlafaxine is also used to treat the symptoms of anxiety causing distress in generalized anxiety disorder (GAD) and social anxiety disorder (social phobia). SSNRIs work by increasing the amount of the two neurotransmitters called serotonin and norepinephrine that are available in certain parts of the brain.

It may take several weeks before the full beneficial effects of this medication are seen.

Your doctor may have suggested this medication for conditions other than the ones listed in these drug information articles. If you have not discussed this with your doctor or are not sure why you are taking this medication, speak to your doctor. Do not stop taking this medication without consulting your doctor.

Depression: The recommended dose of venlafaxine for people with depression is 75 mg daily as a single dose. If you are using the tablets, the daily dose is taken in two or three divided doses with food. If you are using the long-acting capsules, the daily dose is taken in one dose with food. If the expected benefit does not occur after a few weeks, your doctor may gradually increase the dose until improvement is seen.

Generalized anxiety disorder (GAD): For people with GAD, the recommended starting dose of venlafaxine extended release is 37.5 mg daily taken as a single dose with food for 4 to 7 days. Your doctor may gradually increase the dose based on your response to the medication.

Social anxiety disorder (social phobia): The usual recommended starting dose of venlafaxine is 75 mg daily as a single dose. For some people, the doctor may recommend starting with a lower dose of 37.5 mg daily for the first 4 to 7 days of treatment so that they can get used to the medication. The dose can then be increased to 75 mg daily. Your doctor may gradually increase the dose based on your response to the medication.

Many things can affect the dose of medication that a person needs, such as body weight, other medical conditions, and other medications. If your doctor has recommended a dose different from the ones listed here, do not change the way that you are taking the medication without consulting your doctor.

It is important that this medication be taken exactly as prescribed by your doctor. If you miss a dose, take it as soon as possible and continue on with your regular schedule. If it is almost time for your next dose, skip the missed dose and continue on with your regular dosing schedule. Do not take a double dose to make up for a missed one.

Do not give this medication to anyone else, even if they have the same symptoms as you do. It can be harmful for people to take this medication if their doctor has not prescribed it.

Effexor® XR is available in strengths of 37.5 mg, 75 mg, and 150 mg.

37.5 mg: Each extended-release, hard gelatin capsule, with grey cap and peach body, with "W" and "Effexor XR" on the cap and "37.5" on the body in red ink, contains 37.5 mg of venlafaxine.

75 mg: Each extended-release, hard gelatin capsule, with peach cap and body, with "W" and "Effexor XR" on the cap and "75" on the body in red ink, contains 75 mg of venlafaxine.

150 mg: Each extended-release, hard gelatin capsule, with dark orange cap and body, with "W" and "Effexor XR" on the cap and "150" on the body in white ink, contains 150 mg of venlafaxine.

Nonmedicinal ingredients:
For 37.5 mg capsules: D&C Yellow No. 10, D&C Red No. 28, ethylcellulose, FD&C Blue No. 1, gelatin, hydroxypropyl methylcellulose, iron oxide, microcrystalline cellulose, talc, titanium dioxide, and White Tek SB-0007 and/or Opacode Red S-1-15034 ink.
For 75 mg and 150 mg tablets: ethylcellulose, gelatin, hydroxypropyl methylcellulose, iron oxide, microcrystalline cellulose, talc, titanium dioxide, and White Tek SB-0007 and/or Opacode Red S-1-15034 ink.

Venlafaxine should not be taken by anyone who:

• is allergic to venlafaxine or any ingredient of the medication
• is currently taking an MAO inhibitor (e.g., phenelzine, tranylcypromine), has taken one in the last 14 days, or will start treatment with one in the next 14 days

The side effects listed below are not experienced by everyone who takes this medication. If you are concerned about side effects, discuss the risks and benefits of this medication with your doctor. Your health professional may be able to help you deal with some of the effects.

The following side effects may go away as your body becomes used to the medication; check with your doctor if they continue or become bothersome.

Less common
• change in taste sensation
• muscle tension
• yawning

Check with your doctor as soon as possible if any of the following side effects occur:

More common
• changes in vision, such as blurred vision
• decrease in sexual desire or ability
• headache

Less common
• chest pain
• fast or irregular heartbeat
• mood or mental changes
• ringing or buzzing in ears

Rare
• convulsions (seizures)
• difficulty urinating or holding urine
• itching or skin rash
• lightheadedness or fainting, especially when rising suddenly from a sitting or lying position
• lockjaw
• menstrual changes
• swelling
• talking, feeling, and acting with excitement and activity you cannot control
• trouble breathing

Some people may experience side effects other than those listed. Check with your doctor if you notice any symptom that worries you while you are taking this medication.

Allergic reaction: If you develop a skin rash or hives, check with your doctor as soon as possible.

Blood pressure: Treatment with venlafaxine tablets has been associated with modest increases in blood pressure.

Heart disease: People with heart disease should use this medication with caution.

Kidney and liver function: People with reduced kidney or liver function should use this medication with caution.

Drowsiness / reduced alertness: People who take venlafaxine should use caution when driving or operating machinery until they determine that the medication does not impair their ability to do such activities.

Seizures: As with other antidepressants, venlafaxine should be used with caution by people who have had seizures in the past.

Suicidal or agitated behaviour: Adults and children taking this medication may feel agitated (restless, anxious, aggressive, emotional, and feeling not like themselves), or they may want to hurt themselves or others. These symptoms may occur within several weeks after people start taking this medication. People should be closely monitored by their doctor for emotional and behavioural changes.

Stopping the medication: Stopping this medication suddenly may lead to side effects. If you are thinking of stopping the medication, check with your doctor first.

When stopping venlafaxine treatment after more than one week of treatment, it is recommended that the dose of the medication be reduced gradually to prevent symptoms such as anxiety, agitation, confusion, diarrhea, dizziness, dry mouth, fatigue, headache, nausea, loss of appetite, nervousness, sleep disturbances, sweating, and vomiting.

Pregnancy: The safety of venlafaxine in pregnancy has not been established. It has been reported that babies born to pregnant women who have taken medications of this kind during the last trimester of pregnancy may be adversely affected. Physicians and pregnant women should carefully consider the benefits and the risks of all treatment options.

Breast-feeding: Venlafaxine passes into breast milk. Women should not nurse their infants while taking venlafaxine.

Children: The safety and efficacy of this medication for children below the age of 18 have not been established. The use of this medication by children below the age of 18 may cause behavioural and emotional changes, such as suicidal thoughts and behaviour.

The following may affect how venlafaxine works or increase the risk of side effects:

• alcohol
• cimetidine
• nefazodone
• MAO inhibitors (e.g., tranylcypromine, phenelzine, selegiline)
• St. John's wort
• sibutramine
• sumatriptan
• tramadol
• trazodone
• tricyclic antidepressants (e.g., amitriptyline, imipramine)
• trifluoperazine

Venlafaxine may affect how haloperidol works.

If you are taking any of these medications, speak with your doctor or pharmacist. Depending on your specific circumstances, your doctor may want you to:

• stop taking one of the medications,
• change one of the medications to another,
• change how you are taking one or both of the medications, or
• leave everything as is.

An interaction between two medications does not always mean that you must stop taking one of them. In many cases, interactions are intended or are managed by close monitoring. Speak to your doctor about how any drug interactions are being managed or should be managed.

Medications other than those listed above may interact with this medication. Tell your doctor or prescriber about all prescription, over-the-counter (non-prescription), and herbal medications that you are taking. Also tell them about any supplements you take. Since caffeine, alcohol, the nicotine from cigarettes, or street drugs can affect the action of many medications, you should let your prescriber know if you use them.