Venlafaxine

August 8, 2018

About venlafaxine

Venlafaxine is a type of antidepressant often used to treat depression. It is also sometimes used to treat anxiety and panic attacks.

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.

Key facts

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
vomiting
a racing heart
seizures

Side effects

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
headaches
sweating
dry mouth
trouble sleeping
dizziness
feeling sleepy
constipation

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
wheezing
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.

You can report any suspected side effect to the UK safety scheme.

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.

Common questions

How does venlafaxine work?

Venlafaxine is one of a group of antidepressants called serotonin and noradrenaline reuptake inhibitors, or SNRIs. These medicines are thought to work by increasing the levels of mood-enhancing chemicals called serotonin and noradrenaline in the brain.

When will I feel better?

You may see an improvement in your symptoms after a week although it usually takes between 4 and 6 weeks before you feel the full benefits. That's because it takes around a week for venlafaxine levels to build up in your body, and then a few weeks longer for your body to adapt and get used to it.

Don't stop taking venlafaxine just because you feel it is not helping your symptoms. Give the medicine at least 6 weeks to work.

How will it make me feel?

Antidepressants like venlafaxine help to jump start your mood so you feel better. You may notice that you sleep better and get on with people more easily because you're less anxious. You will hopefully take in your stride little things that used to worry you.

Venlafaxine won't change your personality or make you feel really happy. It will simply help you feel like yourself again.

Don't expect to feel better overnight, though. Some people feel worse during the first few weeks of treatment before they begin to feel better.

How long will I take it for?

Once you're feeling better it's likely that you will continue to take venlafaxine for several more months. Most doctors recommend that you take antidepressants for 6 months to 1 year after you no longer feel depressed. Stopping before that time can make depression come back.

Is it safe to take it for a long time?

Venlafaxine is safe to take for a long time. There don't seem to be any lasting harmful effects from taking it for many months and years.

However, taking venlafaxine for more than a year has been linked to a small increased risk of getting diabetes. But you will be regularly checked for this.

What will happen when I come off it?

If you stop taking venlafaxine suddenly you may get unpleasant withdrawal symptoms. These include:

dizziness
feeling sick
numbness or tingling in the hands or feet
trouble sleeping
feeling agitated or anxious
headaches
shaking

Withdrawal symptoms are usually harmless and over within a few days but it's possible to prevent them by reducing the dose gradually when you stop taking this medicine.

Don't stop taking venlafaxine unless your doctor tells you to.

Is venlafaxine better than other antidepressants?

Venlafaxine isn't any better or worse than other antidepressants. However, sometimes people respond better to one antidepressant than to another. If you aren't feeling any better after 6 weeks, talk to your doctor.

Are there other treatments that will help?

Antidepressants, including venlafaxine, are just one of several approaches to treating depression. Other potential treatments include:

talking therapy (such as cognitive behavioural therapy)
exercise programmes
help to get a good night's sleep

Choosing a treatment that's most suitable for you depends on how long you have had depression, your symptoms, whether you have had any previous bouts of depression, whether previous treatment has worked, how likely you are to stick with your treatment, the potential side effects and your preferences and priorities.

Is there any food or drink I need to avoid?

You can eat and drink normally while taking venlafaxine.

Will I gain or lose weight?

Venlafaxine can make you feel less hungry than usual, so you may lose weight when you start taking it. Some people might find they gain weight.

If you start to have problems with your weight while taking venlafaxine, talk to your doctor or pharmacist.

Will it affect my sex life?

The good effects of venlafaxine may, after a while, improve your sex life as your mood lifts and you become interested in life and relationships again.

Some of the possible negative effects include:

men might have problems with getting an erection, or with ejaculating
women might have some vaginal bleeding
both men and women might find they don't reach orgasm the same way as before
you may have a lower sex drive

Any mild sexual side effects might pass after the first couple of weeks. If they don't, and this a problem for you, go back to your doctor to see if there's an alternative antidepressant for you to try.

Will it affect my contraception?

For women, venlafaxine will not affect contraceptive pills or the morning after pill.

Can I drive or ride a bike?

Some people can't concentrate properly while they're taking venlafaxine. It might be best to stop driving and cycling for the first few days of treatment until you know how this medicine makes you feel.

Can I drink alcohol with it?

You can drink alcohol while taking venlafaxine but it may make you feel sleepy. It might be best to stop drinking alcohol during the first few days of treatment until you see how this medicine affects you.

Will recreational drugs affect it?

The sleep-inducing effects of cannabis can add to those of venlafaxine, especially in people who have just started taking it. Cannabis and venlafaxine can also give you a fast heartbeat.

Methadone can make sleepiness worse with venlafaxine.

It can be potentially dangerous to take venlafaxine with:

stimulants like MDMA (ecstasy) or cocaine
hallucinogens like LSD
novel psychoactive substances (which used to be known as legal highs) like mephedrone

Venlafaxine has not been properly tested with recreational drugs. Talk to your doctor if you think you might take any while taking venlafaxine.