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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.
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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 is believed that SNRIs work by increasing the activity of certain chemicals working in our brains called neurotransmitters. 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. Read more about antidepressants. In New Zealand, venlafaxine is available as capsules.

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  you need to, will increase your dose slowly. This allows your body 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 is best to take venlafaxine with food. 
  • Swallow your venlafaxine capsule whole, with a glass of water. Do not crush or chew the capsules. This will release all the medicine at once and cause side effects.
  • Missed dose: If you forget to take your dose and if it is more than 12 hours late, wait until the next day and take your normal dose then. Do not take double the dose. Otherwise, if it is less than 12 hours late, take it as soon as you remember, and then go back to taking as you would normally.
  • Keep taking venlafaxine regularly. It may take a few weeks or months before you notice the full benefits of venlafaxine. If you think venlafaxine is not working for you, do not stop taking it suddenly; speak to your doctor or nurse before stopping. It is usually best to stop taking venlafaxine very slowly to avoid side effects.

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 are taking venlafaxine, especially when you first start treatment. Drinking alcohol while taking venlafaxine can cause drowsiness and affect 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.
  • 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 medications, herbal supplements (such as St. John's wort) and rongoā Māori, so check with your doctor or pharmacist 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 are in the sun, or you may notice a darker tan or redness. When outside, protect your skin by using a good sunscreen (SPF 50+) and wearing a wide-brimmed sunhat and long-sleeved shirts and trousers.

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 is 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 is ok and important to ask about suicidal thoughts and this will not increase risk.  

If you need urgent help or are concerned, phone:

  • Lifeline 0800 543 354 (available 24/7)
  • 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 to a different antidepressant. Read more about medicines and sexual problems.

Other side effects

Side effects What should I do?
  • Feeling sick (nausea) or vomiting
  • Stomach upset
  • Try taking venlafaxine after food
  • Tell your doctor if troublesome and the symptoms are ongoing
  • Feeling sleepy, drowsy, or tired
  • Try taking venlafaxine in the evening
  • Be careful when driving or using tools until you know how this medicine affects you
  • Tell your doctor if troublesome
  • Headache
  • Dry mouth
  • Increased sweating
  • Trouble sleeping

  • These are quite common when you first start taking venlafaxine and usually go away with time
  • Tell your doctor if troublesome
  • Weight changes
  • Tell your doctor 
  • Suicidal thoughts, thoughts of harming yourself, or worsening depression
  • Tell your doctor immediately or ring HealthLine 0800 611 116
  • Changes in heart beat such as fast heart rate or irregular heart beat  
  • Seizures
  • Tell your doctor immediately or ring HealthLine 0800 611 116
  • Signs of serotonin syndrome such as feeling agitated and restless, heavy sweating, shivering, fast heart rate or irregular heart beat, headache, diarrhoea and rigid or twitching muscles
  • You are at increased risk of serotonin syndrome if you recently started taking venlafaxine or recently increased the dose
  • Tell your doctor immediately or ring HealthLine 0800 611 116
Did you know that you can report a side effect to a medicine to CARM (Centre for Adverse Reactions Monitoring)? Report a side effect to a product(external link)

The following links have more information on venlafaxine.

Medsafe consumer information sheets: Enlafax SR(external link)Efexor XR(external link) 
New Zealand Formulary Patient Information: venlafaxine(external link) 
Pharmac Your brand of medicine is changing(external link)


5 questions to ask about your medications(external link) Health Quality and Safety Commission, NZ, 2019 English(external link), te reo Māori(external link)


  1. Venlafaxine(external link) New Zealand Formulary
  2. QT Prolongation with antidepressants(external link) Medsafe NZ, 2013
  3. Venlafaxine and photosensitivity(external link) Medsafe NZ, 2016
  4. The role of medicines in the management of depression in primary care(external link) BPAC, 2017

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Credits: Sandra Ponen, Pharmacist, Healthify He Puna Waiora. Healthify is brought to you by Health Navigator Charitable Trust.

Reviewed by: Angela Lambie, Pharmacist, Auckland

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