Venlafaxine helps many people recover from depression, and has fewer unwanted effects than older antidepressants.
It comes as tablets and capsules which are available only on prescription.
- It usually takes 4 to 6 weeks for venlafaxine to work.
- Side effects such as feeling sick, headaches, sweating, and dry mouth are common. They are usually mild and go away after a couple of weeks.
- Venlafaxine can affect an unborn baby. Tell your doctor straight away if you're trying to get pregnant or become pregnant while taking it.
- Venlafaxine can cause withdrawal symptoms. Don't stop taking it without talking to your doctor.
- Venlafaxine has lots of different brand names including Efexor XL.
Who can and can't take venlafaxine
Venlafaxine can be taken by adults for depression, anxiety and panic attacks.
Check with your doctor before starting to take venlafaxine if you:
- have had an allergic reaction to venlafaxine or any other medicines in the past
- have a heart problem - as venlafaxine can speed up or change your heartbeat
- are trying to become pregnant, are already pregnant or you are breastfeeding - venlafaxine is usually not recommended in pregnancy or while breastfeeding
- have an eye problem called glaucoma because venlafaxine can increase the pressure in your eye
If you have diabetes, venlafaxine can make it more difficult to keep your blood sugar stable. Monitor your blood sugar more often for the first few weeks of treatment with venlafaxine and adjust your diabetes treatment if necessary.
How and when to take it
Take venlafaxine once or twice a day as recommended by your doctor. It's best to take venlafaxine with food so it doesn't make you feel sick.
How much will I take?
The usual starting dose of venlafaxine is 75mg a day. This might be gradually increased to a maximum dose of 375mg.
If you have problems with your liver or kidneys your doctor might prescribe a lower dose.
Venlafaxine tablets and capsules can be either immediate release or extended release. How you take them depends on the type you've been prescribed.
Immediate release tablets release the venlafaxine into your system as soon as you swallow them. You will usually take 37.5mg immediate release tablets twice a day, once in the morning and once in the evening.
Extended release tablets and capsules are released into your system gradually. You will usually take 75mg extended release tablets or capsules once a day. You can choose to take them at any time as long as you stick to the same time every day. If you have trouble sleeping, it's best to take it in the morning.
What if I forget to take it?
If you occasionally forget to take a dose, don't worry. Take your next dose at the usual time. Never take 2 doses at the same time to make up for a forgotten one.
If you forget doses often, it may help to set an alarm to remind you. You could also ask your pharmacist for advice on other ways to help you remember to take your medicine.
What if I take too much?
Ask your doctor for advice straight away. An overdose can lead to potentially serious symptoms such as:
- feeling sleepy
- a racing heart
Like all medicines, venlafaxine can cause side effects in some people, but many people have no side effects or only minor ones. Some of the common side effects of venlafaxine will gradually improve as your body gets used to it.
Common side effects
These side effects happen in more than 1 in 100 people. Keep taking the medicine, but tell your doctor or pharmacist if these side effects bother you or don't go away:
- feeling sick
- dry mouth
- trouble sleeping
- feeling sleepy
Serious side effects
It happens uncommonly (in less than 1 in 100 people), but some people may have serious side effects when taking venlafaxine.
Tell a doctor straight away if you develop:
- headaches, trouble focusing, memory problems, not thinking clearly, weakness, seizures, or losing your balance - these can be signs of low sodium levels
- thoughts about harming yourself or ending your life
- chest pain or pressure, shortness of breath, or a fast or irregular heart beat
- severe dizziness or passing out
- feelings of euphoria, excessive enthusiasm or excitement, or a feeling of restlessness that means you can't sit or stand still
- unexplained muscle pain or weakness
- yellow skin or eyes - this can be a sign of liver problems
- any changes in your eyesight, like blurred vision or dilated pupils
- putting on or losing weight without trying to
- changes in your periods such as heavy bleeding, spotting, or bleeding between periods
Or, if you get any signs of abnormal bleeding including:
- vomiting blood or dark vomit, coughing up blood, blood in your pee, black or red poo - these can be signs of bleeding from the gut
- bleeding from the gums or bruises that appear without a reason or that get bigger
- any bleeding that is very bad or that you cannot stop
Serious allergic reaction
In rare cases, it’s possible to have a serious allergic reaction to venlafaxine.
A serious allergic reaction is an emergency. Contact a doctor straight away if you think you or someone around you is having a serious allergic reaction.
The warning signs of a serious allergic reaction are:
- getting a skin rash that may include itchy, red, swollen, blistered or peeling skin
- tightness in the chest or throat
- having trouble breathing or talking
- swelling of the mouth, face, lips, tongue, or throat
These are not all the side effects of venlafaxine. For a full list see the leaflet inside your medicines packet.
How to cope with side effects
What to do about:
- feeling sick - try taking venlafaxine with or after food. It may also help if you avoid rich or spicy food.
- headaches - make sure you rest and drink plenty of fluids. Don’t drink too much alcohol. Ask your pharmacist to recommend a painkiller. Headaches should usually go away after the first week of taking venlafaxine. Talk to your doctor if they last longer than a week or are severe.
- a dry mouth - chew sugar-free gum or sugar-free sweets
- dizziness - if venlafaxine makes you feel dizzy, stop what you’re doing and sit or lie down until you feel better
- feeling sleepy - cut down the amount of alcohol you drink
- being unable to sleep - take venlafaxine first thing in the morning
- constipation - eat more high-fibre foods such as fresh fruit and vegetables and cereals, and drink plenty of water. Try to exercise more regularly, for example, by going for a daily walk or run. If this doesn't help, talk to your pharmacist or doctor.
You can reduce the chance of having a side effect that bothers you if you take venlafaxine in the evening. That way you're asleep when the level of medicine in your body is highest.
Pregnancy and breastfeeding
Venlafaxine is generally not recommended in pregnancy or while breastfeeding.
No antidepressants are considered completely safe to take in pregnancy or while breastfeeding. Your doctor will want to prescribe venlafaxine when the benefits to you outweigh the risks.
Venlafaxine and similar antidepressants have been linked with a small risk of problems for the unborn baby when they're taken in early or late pregnancy.
Venlafaxine and breastfeeding
Venlafaxine passes into breast milk and has been linked with side effects in breastfed babies.
Tell your doctor if you're trying to get pregnant, become pregnant or if you're breastfeeding.
Cautions with other medicines
Some medicines and venlafaxine can interfere with each other and increase the chances of you having side effects.
Tell your doctor if you're taking these medicines before you start venlafaxine:
- any medicines that affect your heartbeat - as venlafaxine can speed up or change your heartbeat
- any other medicines for depression. Some rarely used antidepressants can interact with venlafaxine to cause very high blood pressure even when they have been stopped for a few weeks.
Mixing venlafaxine with herbal remedies and supplements
Don't take the herbal remedy for depression, St John's wort, while you are being treated with venlafaxine as it will increase your risk of side effects.
Tell your doctor or pharmacist if you are taking any other medicines, including herbal remedies, vitamins or supplements.
How does venlafaxine work?
When will I feel better?
How will it make me feel?
How long will I take it for?
Is it safe to take it for a long time?
What will happen when I come off it?
Is venlafaxine better than other antidepressants?
Are there other treatments that will help?
Is there any food or drink I need to avoid?
Will I gain or lose weight?
Will it affect my sex life?
Will it affect my contraception?
Can I drive or ride a bike?
Can I drink alcohol with it?
Will recreational drugs affect it?