Brain cells, called neurons, release a number of chemicals which go on to stimulate other neurons. This leads 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. Selective serotonin reuptake inhibitors (SSRIs) like fluoxetine increase the amount of circulating serotonin available in your brain. Altering the balance of the chemicals in the brain can help the symptoms of Raynaud's.
Before taking fluoxetine
Some medicines are not suitable for people with certain conditions, and sometimes a medicine may only be used if extra care is taken. For these reasons, before you start taking fluoxetine it is important that your doctor knows:
- If you are pregnant, trying for a baby or breast-feeding.
- If you have any problems with the way your liver works.
- If you have a heart condition.
- If you have epilepsy.
- If you have sugar diabetes (diabetes mellitus).
- If you have an eye problem called glaucoma.
- If you have ever had a bleeding disorder.
- If you have ever had abnormally 'high' moods, called mania.
- If you are being treated with electroconvulsive therapy (ECT).
- If you have ever had an allergic reaction to a medicine.
- If you have taken an antidepressant known as a monoamine-oxidase inhibitor (MAOI) within the previous two weeks.
- If you are taking any other medicines. This includes any medicines you are taking which are available to buy without a prescription, such as herbal and complementary medicines.
How to take fluoxetine
- Before you start the treatment, read the manufacturer's printed information leaflet from inside the pack. It will give you more information about fluoxetine and will provide you with a full list of the side-effects which you may experience from taking it.
- Take fluoxetine exactly as your doctor tells you to - the directions will be printed on the label of the pack to remind you of what your doctor said. As a guide, if you are being treated for depression or OCD, it is usual to be prescribed 20 mg (one capsule or 5 ml liquid medicine) as a once-daily dose. Your dose may later be increased. For people being treated for bulimia, the usual daily dose is 60 mg (three capsules or 15 ml liquid medicine). You can generally take fluoxetine at a time to suit you, but try to take your doses at the same time of day, each day.
- You can take fluoxetine before or after food. Swallow the capsules whole with a drink of water - do not chew or open the capsules. If you have difficulty swallowing capsules, let your doctor know, as you could be prescribed liquid medicine to take instead.
- If you forget to take a dose, take it as soon as you remember. If you do not remember until the following day, skip the missed dose. Do not take two doses together to make up for a forgotten dose.
Getting the most from your treatment
- You may feel that fluoxetine is not working for you straightaway. It can take a week or two after starting this treatment before the effect begins to build up, and 4-6 weeks before you feel the full benefit. Do not stop taking it after a week or two, feeling 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 are taking fluoxetine, you may have thoughts about harming yourself or ending your life. These thoughts may also be associated with your condition. It is very important that you tell your doctor about this if it happens.
- Do not stop taking fluoxetine 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 when this becomes necessary. You should expect that a course of treatment will last for several months. This is normal and helps to prevent your symptoms from recurring.
- If you drink alcohol, ask your doctor for advice. Your doctor is likely to recommend that you do not drink alcohol while you are on fluoxetine.
- If you have diabetes, you may need to check your blood glucose more frequently, as fluoxetine may affect the levels of sugar in your blood. Your doctor will be able to advise you about this.
- If you buy any medicines, check with a pharmacist that they are safe to take with fluoxetine. This is because several medicines which are available from general retail outlets can interfere with this treatment. In particular, do not take the herbal remedy St John's wort, and ask for advice before buying any anti-inflammatory painkillers.
- A few people taking fluoxetine find that their skin is more sensitive to sunlight than normal. Until you know how your skin reacts, use a sun cream with a high sun protection factor (SPF) in strong sunlight.
- There are several types of antidepressants and they differ in their possible side-effects. If you find that fluoxetine does not suit you then let your doctor know, as another may be found that will.
Can fluoxetine cause problems?
Along with their useful effects, most medicines can cause unwanted side-effects although not everyone experiences them. The table below contains some of the most common ones associated with fluoxetine. You will find a full list in the manufacturer's information leaflet supplied with your medicine. The unwanted effects often improve as your body adjusts to the new medicine, but speak with your doctor or pharmacist if any of the following continue or become troublesome.
Common fluoxetine side-effects and what to do.
Feeling or being sick, indigestion, diarrhoea - Stick to simple foods
Dry mouth - Try chewing sugar-free gum or sugar-free sweets
Headache - Ask your pharmacist to recommend a suitable painkiller
Mood changes such as feeling anxious, nervous, agitated or forgetful. Feeling restless or shaky - These usually settle within a few days. If any becomes troublesome or severe, speak with your doctor
Feeling dizzy, tired or weak. Blurred vision - If this happens, do not drive or use tools or machines until you feel better
Flushing, sweating, difficulty sleeping, lack of appetite, loss of weight, aches and pains, reduced sexual drive or ability, yawning, palpitations, itching, changes in taste - If any of these become troublesome, speak with your doctor
Important: a few people taking fluoxetine have developed an allergic-type reaction. You should contact your doctor straightaway if you develop any swelling around your face, any difficulties breathing, or a severe rash.
If you experience any other symptoms that you think may be due to this medicine, speak with your doctor or pharmacist for further advice.
How to store fluoxetine
- Keep all medicines out of the reach and sight of children.
- Store in a cool, dry place, away from direct heat and light.