Venlafaxine
Sounds like 'ven-la-FAX-een'
Key points about venlafaxine
- Venlafaxine is used to treat severe depression, anxiety disorder or panic disorder.
- Venlafaxine is also called Enlafax XR® or Efexor-XR® .
- Find out how to take it safely and possible side effects.

Venlafaxine is used to treat severe depression, anxiety disorder or panic disorder. It is one of a group of medicines known as serotonin-noradrenaline reuptake inhibitors (SNRIs).
It's believed that SNRIs work by increasing the activity of certain chemicals (neurotransmitters) in our brains. These pass signals from one brain cell to another. Although we don’t know for certain, the neurotransmitters that are most likely to be involved in depression and some other conditions are thought to be serotonin and noradrenaline.
In Aotearoa New Zealand, venlafaxine is available as capsules of 37.5 mg, 75 mg and 150 mg strengths. Read more about antidepressants.
If you need help or want to talk to somebody about your mental health, you can get support from any of the following:
- Free call or text 1737 any time for support from a trained counsellor.
- Lifeline 0800 543 354 (0800 LIFELINE) or free text 4357 (HELP).
- Suicide Crisis Helpline 0508 828 865 (0508 TAUTOKO).
- Healthline 0800 611 116.
- Samaritans 0800 726 666.
- The dose of venlafaxine will be different for different people. Your doctor will usually start you on a low dose and, if needed, will increase your dose slowly. This allows your body time to get used to the medicine and reduces side effects.
- Always take your venlafaxine exactly as your doctor has told you. The pharmacy label on your medicine will tell you how much venlafaxine to take, how often to take it, and any special instructions.
- Timing: Take venlafaxine once a day, at the same time each day, either in the morning OR in the evening. You can take it at a time that suits you, but try to take your doses at the same time each day. It's best to take venlafaxine with food.
- Swallow your venlafaxine capsule whole, with a glass of water: Don't crush or chew the capsules as this will release all the medicine at once and increase the chance of side effects.
- Missed dose: If you forget to take your dose and it’s less than 12 hours since your missed dose, take it as soon as you remember. If it’s more than 12 hours late, skip the dose and take the next dose at your usual time. Don’t take double the dose.
- Keep taking venlafaxine regularly: It may take a few weeks before you notice any benefits and even longer to feel the full benefits of venlafaxine. If you think venlafaxine isn't working for you, don't stop taking it suddenly. Talk to your doctor or nurse before stopping.
- Don't stop taking venlafaxine suddenly: Talk to your doctor before stopping. It's best to stop taking venlafaxine very slowly to avoid side effects.
- It's important to take it as prescribed: See tips to help you remember to take your medicines regularly.
Here are some things to know when you're taking venlafaxine. Other things may be important as well, so ask your healthcare provider what you should know about.
- Alcohol: Avoid alcohol while you're taking venlafaxine, especially when you first start treatment. Drinking alcohol while taking venlafaxine can cause drowsiness and affect your concentration, putting you at risk of falls and other accidents. It can also cause agitation, aggression and forgetfulness. If you do drink alcohol, drink only small amounts and see how you feel. Do not stop taking your medication.
- Driving: Venlafaxine can make you sleepy and dizzy so be careful when driving or using tools until you know how it affects you.
- High blood pressure (hypertension): If you have high blood pressure, you may need to check your blood pressure more often, especially when you first start venlafaxine, because it can cause an increase in blood pressure.
- Other medicines: Venlafaxine interacts with many other medicines (such as ibuprofen and diclofenac), herbal supplements (such as St. John's wort) and rongoā Māori, so check with your healthcare provider before starting venlafaxine or before starting any new medicines or products.
- Sun protection: Venlafaxine can make your skin more sensitive to the sun. You may get a burning, tingling feeling on your skin when you're in the sun, or you may notice a darker tan or redness. When you're outside, protect your skin by using a good sunscreen (SPF 50+) and wearing a wide-brimmed sunhat and clothing that covers your arm and legs.
- Pregnant, pregnancy and breastfeeding: Tell your doctor if you become pregnant, are planning a pregnancy or want to start breastfeeding.
Like all medicines, venlafaxine can cause side effects, although not everyone gets them. Often side effects improve as your body gets used to the new medicine.
Suicidal behaviour
The use of antidepressants has been linked with an increase in suicidal thoughts and behaviour. Children, teenagers, young adults and people with a history of suicidal behaviour are particularly at risk.
This is most likely during the first few weeks of starting an antidepressant or if the dose is changed. It's important to look for signs of suicidal behaviour such as agitation or aggression and ask about suicidal thoughts, self-harm, worsening of low mood, If you notice any of these signs, contact your doctor immediately. It's ok and important to ask about suicidal thoughts and this won't increase the risk.
If you need urgent help or are concerned, phone:
- Lifeline 0800 543 354 (available 24 hours a day)
- Healthline 0800 611 116, who can give you the phone number for your local mental health crisis line.
Sexual side effects
Venlafaxine can cause reduced sexual drive, lack of libido and problems keeping an erection. It’s important to talk to your healthcare provider if you get these effects, as they can be difficult to deal with and may not go away. Your healthcare provider may be able to suggest treatment or may reduce the dose of venlafaxine or change you to a different antidepressant. Read more about medicines and sexual problems.
Other side effects
Side effects | What should I do? |
---|---|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Read more about medicines and side effects and reporting a reaction you think might be a side effect.
The following links have more information on venlafaxine.
Resources
Venlafaxine(external link) New Zealand Formulary Patient Information, NZ
Enlafax SR(external link), Efexor XR(external link) Medsafe consumer information sheets, NZ
Your brand of medicine is changing(external link) Pharmac, NZ
Brochures
Medicines and side effects(external link) Healthify He Puna Waiora, NZ, 2024
Stopping antidepressants: be cautious and go slow(external link) Medsafe, NZ, 2023
5 questions to ask about your medications(external link) Health Quality and Safety Commission, NZ English(external link), te reo Māori(external link)
References
- Venlafaxine(external link) New Zealand Formulary
- Venlafaxine(external link) Medsafe Data sheet, NZ, 2024
- QT Prolongation with antidepressants(external link) Medsafe NZ, 2013
- Venlafaxine and photosensitivity(external link) Medsafe NZ, 2016
- The role of medicines in the management of depression in primary care(external link) BPAC, 2017
- Stopping antidepressants – be cautious and go slow(external link) Medsafe, NZ, 2023
- Enlafax – monitoring to continue(external link) Medsafe, NZ, 2018
-
Venlafaxine (Enlafax XR) all strengths: Supply issue resolved(external link) Pharmac, NZ, 2025
Brochures
Medicines and side effects
Healthify He Puna Waiora, NZ, 2024
Stopping antidepressants: be cautious and go slow
Medsafe, NZ, 2023
Health Quality and Safety Commission, NZ, 2019 English, te reo Māori
Credits: Sandra Ponen, Pharmacist, Healthify He Puna Waiora. Healthify is brought to you by Health Navigator Charitable Trust.
Reviewed by: Stephanie Yee, Pharmacist, Auckland
Last reviewed:
Page last updated: