Venlafaxine

Generic name

Venlafaxine

Active ingredient

Venlafaxine (variants: venlafaxine hydrochloride)

Product type

Small-molecule medicine

Drug class

SNRIs

Brand names

UK Efexor XL, Vencarm XL, Viepax XL · US Effexor XR

Routes

Oral

Dosage forms

Tablet, Capsule, Extended-release (modified-release) tablet

Also known as

Venlafaxine XL, venlafaxine hydrochloride, Efexor XL

Usual preparations

Taken by mouth as tablets or capsules, including prolonged-release forms. (summary of the cited reference, not a prescription)

Onset and duration

The NHS and MedlinePlus say it may take several weeks or longer to feel the full benefit of venlafaxine.

Monitoring

UK product information says blood pressure should be reviewed periodically, after treatment starts and after dose increases, and the US label recommends regular blood pressure monitoring.

Availability by country

Legal status differs between countries and can change; each row cites the document it was taken from and applies only to the country named.

What it is used for

• Depression

How it works in the body

Venlafaxine is a serotonin and noradrenaline reuptake inhibitor (SNRI). SNRIs are thought to work by raising the levels of the chemical messengers serotonin and noradrenaline in the brain.

Cautions and interactions

• The NHS says venlafaxine is not suitable for everyone, and lists diabetes, epilepsy, heart problems, glaucoma and a bleeding disorder among the conditions that need care.
• An earlier allergic reaction to venlafaxine is also on the NHS list of reasons it may not be suitable.
• UK patient leaflets ask people with a history of high blood pressure, heart problems or an abnormal heart rhythm to talk to their doctor before starting.
• UK product information says patients should be screened for high blood pressure and that existing high blood pressure should be controlled before treatment starts.
• The NHS says venlafaxine can increase the pressure in the eye and may raise the risk of a fit or seizure in people with epilepsy.
• UK patient leaflets say monoamine oxidase inhibitors (MAOIs), another type of antidepressant that is also used for Parkinson's disease, must not be taken with venlafaxine, and ask people who have taken one recently to tell their doctor.
• The NHS says some rarely used antidepressants can affect venlafaxine and cause very high blood pressure.
• The NHS advises against using the herbal supplement St John's wort with venlafaxine because it raises the risk of side effects.
• The NHS lists anti-inflammatory painkillers such as aspirin and ibuprofen, and anticoagulants such as warfarin and apixaban, among medicines that may not mix well with venlafaxine.
• Some UK patient leaflets name tramadol, triptans for migraine and dextromethorphan, found in some cough medicines, as examples of medicines that raise the risk of serotonin syndrome.
• The NHS says alcohol may make a person feel sleepy while taking venlafaxine and suggests avoiding it in the first few days, and its main venlafaxine page says it is best not to drink because alcohol can raise the risk of side effects.
• The NHS suggests it might be best to avoid driving and cycling for the first few days of treatment, until a person knows how the medicine makes them feel.
• The NHS says pregnancy and breastfeeding call for a discussion of the risks and benefits with the doctor.

Interactions

Interactions documented in the official sources cited on each card. The list covers the medicines represented on this site and is not exhaustive; how the interaction data is compiled.

No pair records for this medicine are in the sources currently represented by Anatomy Nexus. Absence from this list does not mean no interaction exists.

Same-class and related medicines

Same class: SNRIs

Medicines that share the class of Venlafaxine. They are separate medicines with their own licences, doses and interactions, not alternative names for Venlafaxine.

Related medicines

Medicines often discussed alongside Venlafaxine: used together, compared with it, or acting on the same problem by a different route.

Key facts

What is venlafaxine used for?

Venlafaxine is an antidepressant medicine. It belongs to a group called serotonin and noradrenaline reuptake inhibitors, or SNRIs, and it is used to treat depression. It is available only on prescription. Serotonin and noradrenaline are chemical messengers in the brain, and SNRIs are thought to work by raising their levels. The NHS and MedlinePlus say it may take several weeks or longer to feel the full benefit. UK product information lists standard tablets as well as prolonged-release tablets and capsules, which release the medicine slowly. The NHS says venlafaxine is not suitable for everyone, and it lists diabetes, epilepsy, heart problems, glaucoma and a bleeding disorder among the conditions that call for extra care. An earlier allergic reaction to venlafaxine is another reason it may not be suitable.

How is venlafaxine taken and stopped?

The NHS says venlafaxine is usually taken with food. For a person who has trouble sleeping, the NHS says the morning is the best time to take it. MedlinePlus says a missed dose is taken once it is remembered, unless it is almost time for the next one, and that doses are not doubled up. The NHS adds that an alarm can help if doses are often forgotten. Stopping suddenly can cause withdrawal symptoms, although the NHS says venlafaxine is not addictive. The NHS says a person who wants to stop should speak to the doctor first. The doctor will usually lower the dose gradually over several weeks or months, and this can take longer after long-term use. Stopping too early can also let depression come back.

What side effects can venlafaxine cause?

Headaches, sweating and a dry mouth are among the common side effects. The NHS says most side effects should ease after a couple of weeks as the body gets used to the medicine. It says headaches usually go away after the first week, and that a dry mouth which does not go away after a week or two is worth raising with the doctor. If dizziness or drowsiness occurs, the NHS advises against driving, riding a bike or using machinery until it has gone away. The NHS says that anyone taking venlafaxine who thinks they may be having serious side effects can call NHS 111. It lists the signs of serotonin syndrome as a fast heartbeat, sweating, shaking, twitching muscles and feeling confused or agitated. The NHS says to call 999 if the lips, mouth, throat or tongue suddenly swell or there is difficulty breathing, which can be signs of a serious allergic reaction (anaphylaxis).

Low mood, self-harm and urgent help

The NHS says it is uncommon, but some people have suicidal thoughts or an urge to self-harm when they start an antidepressant. People aged 24 or under, or who have had these thoughts before, may be most at risk. The NHS says to contact a GP, or go to A&E, for thoughts of killing or harming oneself at any time during treatment. If a person is in danger or cannot keep themselves safe, the NHS says to call 999 or go to A&E. For urgent mental health help that is not an emergency, the NHS points to NHS 111 (mental health option). The Samaritans on 116 123 are free to call at any time. The NHS also suggests that telling a relative or close friend about starting an antidepressant can help them notice changes in behaviour.

Venlafaxine and blood pressure

Venlafaxine can raise blood pressure. UK product information says dose-related rises in blood pressure are common, and that severe rises needing immediate treatment have been reported since the medicine came on the market. It says patients should be screened for high blood pressure and that existing high blood pressure should be controlled before treatment starts. It also says blood pressure should be reviewed periodically, after treatment starts and after dose increases. The US label describes dose-related rises in blood pressure and recommends regular blood pressure monitoring. UK patient leaflets ask people with a history of high blood pressure, heart problems or an abnormal heart rhythm to talk to their doctor before starting. The NHS says venlafaxine can make the heart beat faster or cause an irregular heartbeat. It also says some rarely used antidepressants can affect venlafaxine and cause very high blood pressure.

Other medicines, alcohol and pregnancy

The NHS advises against using the herbal supplement St John's wort with venlafaxine because it raises the risk of side effects. UK patient leaflets say monoamine oxidase inhibitors (MAOIs), another type of antidepressant, must not be taken with venlafaxine, and they ask people who have taken one recently to tell their doctor. The NHS lists anti-inflammatory painkillers such as aspirin and ibuprofen, and anticoagulants such as warfarin and apixaban, among medicines that may not mix well with it. Some UK leaflets name tramadol, triptans for migraine and dextromethorphan, found in some cough medicines, as examples that raise the risk of serotonin syndrome. The NHS says alcohol may make a person feel sleepy, and its main venlafaxine page says it is best not to drink because alcohol can raise the risk of side effects. The NHS says pregnancy and breastfeeding call for a discussion of the risks and benefits with the doctor.

Frequently asked questions