Efexor (venlafaxine)

How does it work?

Efexor tablets contain the active ingredient venlafaxine hydrochloride, which is a type of antidepressant known as a serotonin and noradrenaline reuptake inhibitor (SNRI). This type of medicine acts on nerve cells in the brain.

In the brain there are numerous different chemical compounds called neurotransmitters. These act as chemical messengers between the nerve cells. Serotonin and noradrenaline are two such neurotransmitters and have various functions that we know of.

When serotonin and noradrenaline are released from nerve cells in the brain they act to lighten mood. When they are reabsorbed into the nerve cells, they no longer have an effect on mood. It is thought that when depression occurs, there may be a decreased amount of serotonin and noradrenaline released from nerve cells in the brain.

Venlafaxine works by preventing serotonin and noradrenaline from being reabsorbed back into the nerve cells in the brain. This helps prolong the mood lightening effect of any released serotonin and noradrenaline. In this way, venlafaxine helps relieve depression. It is also helpful for relieving depression that is accompanied by anxiety.

Once you are feeling better, your doctor will usually ask you to continue taking this medicine to minimise the chances of your depression coming back, or to prevent you from becoming depressed in the future. The length of time you take the medicine will vary from person to person, but should be for at least six months after things are back to normal.

It may take between two to four weeks for the benefits of this medicine to appear, so it is very important that you keep taking it, even if it doesn't seem to make much difference at first. If you feel your depression has got worse, or if you have any distressing thoughts or feelings in these first few weeks, then you should talk to your doctor.

What is it used for?

Depressive illness, including depression associated with anxiety.

Warning!

Depression is associated with an increased risk of suicidal thoughts, self-harm, and suicide. You should be aware that this medicine may not start to make you feel better for at least two to four weeks. However, it is important that you keep taking it in order for it to work properly and for you to feel better. If you feel your depression or anxiety has got worse, or if you have any distressing thoughts or feelings about suicide or harming yourself in these first few weeks, or indeed at any point during treatment or after stopping treatment, then it is very important to talk to your doctor.

This medicine may reduce your ability to drive or operate machinery safely. Do not drive or operate machinery until you know how this medicine affects you and you are sure it won't affect your performance.

It is recommended that you avoid drinking alcohol while taking this medicine.

You should not suddenly stop taking this medicine, as this can cause withdrawal symptoms such as headaches, tremor, agitation or anxiety, nausea, vomiting, sweating, dizziness, palpitations, diarrhoea, pins and needles sensations, emotional instability, difficulty sleeping and abnormal dreams. Withdrawal symptoms are temporary and are not due to addiction or dependence on the medicine. They can usually be avoided by stopping the medicine gradually, usually over a period of weeks or months, depending on your individual situation. Follow the instructions given by your doctor when it is time to stop treatment with this medicine. On rare occasions some people have experienced withdrawal symptoms after accidentally missing a dose of this medicine.

The use of venlafaxine has been associated with the development of unpleasant or distressing restlessness and the need to move about, often accompanied by an inability to sit or stand still. This is most likely to occur within the first few weeks of treatment. If you experience these symptoms you should consult your doctor.

This medicine may cause your blood pressure to increase, particularly if you are taking doses higher than 200mg per day. It is recommended that your blood pressure is regularly monitored while you are taking this medicine. If your blood pressure does increase, your doctor may need to reduce your dose of this medicine or stop treatment with it altogether.

This medicine can occasionally cause your blood pressure to drop when you move from a lying down or sitting position to sitting or standing, especially when you first start taking the medicine. This may make you feel dizzy or unsteady. To avoid this try getting up slowly. If you do feel dizzy, sit or lie down until the symptoms pass.

This medicine may sometimes cause an increase in blood cholesterol levels, and for this reason your doctor may want to monitor your cholesterol levels while you are taking this medicine.

Antidepressants may cause the amount of sodium in the blood to drop - a condition called hyponatraemia. This can cause symptoms such as drowsiness, confusion, muscle twitching or convulsions. Elderly people may be particularly susceptible to this effect. You should consult your doctor if you develop any of these symptoms while taking this medicine so that your blood sodium level can be checked if necessary.

Following a review of data from clinical trials of venlafaxine in children under 18 years of age, the Committee on Safety of Medicines has concluded that venlafaxine is ineffective for treating depressive illness in this age group and actually increases the risk of harmful outcomes such as self-harm and potentially suicidal behaviour. Venlafaxine is not licensed for any use in children aged under 18 years and should not be used to treat depressive illness in this age group. It is not recommended for other uses in this age group as its safety and efficacy have not been established.

Use with caution in

Elderly people

Decreased kidney function

Decreased liver function

Liver cirrhosis

Young adults

History of suicidal behaviour or thoughts

History of mania or hypomania

History of drug dependence or abuse

History of fits (seizures), eg epilepsy

People also receiving electroconvulsive therapy (ECT)

People taking antipsychotic medicines

People at increased risk of bleeding

People taking medicine to prevent blood clotting (anticoagulants, eg warfarin)

Heart disease

People who have recently had a heart attack

Raised pressure in the eye (intraocular pressure), eg glaucoma

People with a known risk for closed-angle glaucoma.

Not to be used in

Children and adolescents under 18 years of age

People who have taken a monoamine-oxidase inhibitor (MAOI) in the last 14 days (see below for more information)

People with a very high risk of abnormal heart beats (ventricular arrhythmias), such as people with significant left-sided heart failure or uncontrolled high blood pressure

Uncontrolled epilepsy

Breastfeeding.

This medicine should not be used if you are allergic to one or any of its ingredients. Please inform your doctor or pharmacist if you have previously experienced such an allergy. If you feel you have experienced an allergic reaction, stop using this medicine and inform your doctor or pharmacist immediately.

Pregnancy and breastfeeding

Certain medicines should not be used during pregnancy or breastfeeding. However, other medicines may be safely used in pregnancy or breastfeeding providing the benefits to the mother outweigh the risks to the unborn baby. Always inform your doctor if you are pregnant or planning a pregnancy, before using any medicine.

The safety of this medicine in pregnancy has not been established. It is not recommended for use during pregnancy unless considered essential by your doctor. There is the potential that the medicine could cause withdrawal symptoms in the new-born baby if the medicine is taken by the mother in the third trimester or up until birth. Seek medical advice from your doctor if you get pregnant or plan to have a baby while you are taking this medicine. If you get pregnant and decide to stop taking venlafaxine you should not do so suddenly - see the warning above about withdrawal symptoms.

This medicine passes into breast milk. As this could be harmful to a nursing infant, mothers taking this medicine should either not breastfeed, or not take this medicine. This will depend on how important the medicine is for the mother's health. Seek medical advice from your doctor.

Label warnings

Take this medication with or after food.

Warning. May cause drowsiness. If affected do not drive or operate machinary.

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