Venlafaxine

  • It may take a week or two after starting this treatment before you begin to feel the benefit. Do not stop taking venlafaxine, thinking it is not helping.
  • Tell your doctor if you feel that you are getting worse or if you experience any troublesome side-effects.
  • Venlafaxine may slow your reactions. If this happens, do not drive or use tools or machines.
Type of medicine A serotonin and noradrenaline reuptake inhibitor (SNRI) antidepressant
Used for Depression in adults
Anxiety disorder in adults
Also called Alventa XL®, Depefex® XL, Efexor® XL, Foraven XL®, Mentaven® XL, Politid XL®, Rodomel® XL, Tifaxin XL®, Tanpular® XL, Venaxx XL®, Venablue® XL, Venlalic® XL, Venlaneo® XL, Vensir XL®, Vexarin® XL, ViePax® XL, Winfex® XL
Available as Tablets
Modified-release tablets and modified-release capsules. Modified-release tablets and capsules release venlaxine slowly over 24 hours to give a longer action

Anyone can develop depression. It can develop for no apparent reason or it may be triggered by a life event such as a relationship problem, bereavement, or illness. 

Brain cells called neurons, release a number of chemicals which go on to stimulate other neurons leading to electrical impulses which result in many functions controlled by the brain. Serotonin is one such chemical in the brain. Once released, it stimulates other neurons and is then taken back up into the neuron cells and recycled. Antidepressants like venlafaxine increase the amount of circulating serotonin available in the brain. This may help depression symptoms in some people

Although venlafaxine is often used to treat depression, it can also reduce the symptoms of anxiety disorders. This is because an imbalance of the same chemicals in the brain is thought to be involved in these conditions also.

Before taking venlafaxine make sure your doctor or pharmacist knows:

  • If you are pregnant, trying for a baby or breast-feeding.
  • If you have high blood pressure, heart or heart rhythm problems.
  • If you have liver or kidney problems.
  • If you have diabetes.
  • If you have epilepsy.
  • If you or any close family members have ever had abnormally 'high' moods.
  • If you have glaucoma (increased pressure in your eye).
  • If you have ever had a bleeding disorder.
  • If you are taking other medicines, including those available to buy without a prescription, herbal and complementary medicines.
  • If you have ever had an allergic reaction to this or to any other medicine.
  • Before starting this treatment, read the manufacturer's printed information leaflet from inside the pack.
  • Take venlafaxine exactly as your doctor has told you.
  • Take your doses with a snack or just after eating a meal.
  • If you have been supplied with modified-release venlafaxine (these have 'XL' after the brand name) you should swallow these tablets or capsules whole. They should not be chewed or crushed.
  • Try to take venlafaxine at the same time(s) each day to avoid missing any doses.
  • If you do forget to take a dose, take it as soon as you remember unless it is nearly time for your next dose, in which case leave out the missed dose. Do not take two doses together to make up for a forgotten dose.
  • You may feel that venlafaxine is not working for you straightaway. It can take a week or two after starting this treatment before the effect builds up, and up to four weeks before you feel the full benefit. Do not stop taking it after a week or so, thinking it is not helping.
  • Try to keep your regular appointments with your doctor. This is so your doctor can check on your progress.
  • While you feel depressed or are taking venlafaxine, you may have thoughts about harming yourself or ending your life. It is very important that you tell your doctor about this if it happens.
  • Venlafaxine may slow your reactions or make you sleepy. If this happens, do not drive or use tools or machines.
  • If you buy any medicines, check with a pharmacist that they are safe to take with venlafaxine.
  • There are several types of antidepressants and they differ in their possible side-effects. If you find that venlafaxine does not suit you then let your doctor know, as another may be found that will.
  • If you have diabetes you may need to check your blood glucose more frequently, as venlafaxine may affect the levels of sugar in your blood. Your doctor will be able to advise you about this.
  • If you are taking venlafaxine for depression, you should expect that a normal course of treatment will last for around six months after your symptoms have eased.
  • Do not stop taking venlafaxine unless your doctor tells you to do so. Stopping treatment suddenly can cause problems and your doctor will probably want you to reduce your dose gradually if this is necessary.

Along with their useful effects, most medicines can cause unwanted side-effects although not everyone experiences them. These usually improve as your body adjusts to the new medicine, but speak with your doctor or pharmacist if any of the following side-effects continue or become troublesome.

Common venlafaxine side-effects What can I do if I experience this?
Feeling or being sick Stick to simple foods. Try eating smaller meals but more regularly
Headache Ask your pharmacist to recommend a suitable painkiller. If the headache continues, speak with your doctor
Feeling dizzy, tired or sleepy If this happens, do not drive or use tools or machines
Dry mouth Try chewing sugar-free gum or sucking sugar-free sweets
Constipation Try to eat a well-balanced diet containing fruit and vegetables and drink plenty of water
Sweating Take care not to become overheated during exercise or hot weather
Lack of appetite, chills, feeling your heart pounding, changes in weight, increased blood pressure, yawning, difficulty sleeping, increased cholesterol levels, eyesight problems, hot flushes, urinary problems, difficulties having sex, tingling feelings or numbness, changes in menstrual periods, and feeling nervous, shaky or confused If any of these become troublesome, speak with your doctor

If you experience any other symptoms which you think may be due to this medicine, speak with your doctor or pharmacist.

  • Keep all medicines out of the reach and sight of children.
  • Store in a cool, dry place, away from direct heat and light.
  • Never take more than the prescribed dose. If you suspect that someone has taken an overdose of this medicine, go to the accident and emergency department of your local hospital at once. Take the container with you, even if it is empty.
  • If you are having an operation or dental treatment tell the person carrying out the treatment which medicines you are taking.
  • This medicine is for you. Never give it to other people even if their condition appears to be the same as yours.
  • Never keep out-of-date or unwanted medicines. Take them to your local pharmacy which will dispose of them for you.
  • If you have any questions about this medicine ask your pharmacist.

Further reading & references

  • British National Formulary; 62nd Edition (Sep 2011) British Medical Association and Royal Pharmaceutical Society of Great Britain, London
  • Manufacturer's PIL, Efexor® XL,; Manufacturer's PIL, Efexor® XL, Pfizer Limited, electronic Medicines Compendium. Dated October 2011.

Disclaimer: This article is for information only and should not be used for the diagnosis or treatment of medical conditions. EMIS has used all reasonable care in compiling the information but make no warranty as to its accuracy. Consult a doctor or other health care professional for diagnosis and treatment of medical conditions. For details see our conditions.

Original Author:
Helen Allen
Current Version:
Peer Reviewer:
Dr Hannah Gronow
Last Checked:
19/01/2012
Document ID:
1508 (v27)
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