Family doctor

Brand names: Tegretol and Teril

Use: Epilepsy, bipolar disorder (also known as manic depression), alcohol withdrawal, certain painful conditions (see below), diabetes insipidus (not sugar diabetes).

Carbamazepine (car-bar-maz-ee-peen) has been available for many years, and is also known as the brand names Tegretol and Teril.

Carbamazepine is a very effective treatment for epilepsy, however it doesn't treat every type of epilepsy, and may need to be used with another medicine for best results.

Some unusual painful conditions which may not improve much with regular pain relievers can be improved by the use of carbamazepine. However, this should only ever be under the supervision of a doctor - do not borrow someone else's carbamazepine because you have pain! Carbamazepine has been shown to be effective in nerve pain, e.g. Trigeminal neuralgia (try-gem-in-al new-ral-ga) which is severe sharp pain in parts of the face. Another example of nerve pain which carbamazepine can be used for is pain after shingles (post-herpetic neuralgia).

Carbamazepine can be used on its own or together with other medicines in the treatment of manic-depression (bipolar disorder).

Carbamazepine is very occasionally used for an unusual condition called diabetes insipidus - this is not related at all to sugar diabetes (diabetes mellitus).

Carbamazepine can come in different forms according to the brand used, including regular tablets, controlled-release tablets and caramel-flavoured mixture. The controlled-release tablets can give more constant levels of the medicine in the body during the day, so can be used twice a day. Different brands of carbamazepine do vary a little, so it is usually recommended to continue to use the same brand all of the time.

When starting carbamazepine it is usually to start with a low dose, then to be slowly increased until you get the best effect. This will give less side effects than if you started with a high dose from the first day.

Cautions:

• Carbamazepine should only be taken if prescribed by your doctor for your treatment. Never give your medicine to anyone else to take.
• Carbamazepine should not be used by people who are allergic to carbamazepine, or to some antidepressants. Some heart conditions or a history of bone-marrow depression or porphyria may mean that carbamazepine is not recommended.
• Tegretol should not be used for absence (or petit mal) seizures.
• Special care needs to be taken in people with a history of heart, liver or kidney disease or damage, side effects of the blood with other medicines, or interrupted courses of therapy with carbamazepine. In these cases the doctor may sometimes choose not to use carbamazepine.
• The elderly may be especially sensitive to side effects of carbamazepine, and therefore are started on a lower dose and watched carefully for side effects.
• Glaucoma needs to be monitored if carbamazepine is taken.

Side effects:

Talk to a doctor immediately if symptoms such as fever, sore throat, skin rash, mouth ulcers, bruising or bleeding develop while you are on this medicine (and make sure they know you are taking carbamazepine). These can be symptoms of very rare but serious side effects of carbamazepine which need to be treated immediately.

The following unwanted effects are common when first starting carbamazepine, in elderly people, and if the initial dose is a bit high:

• Reactions affecting the head e.g. dizziness, headache, lack of co-ordination, tiredness or sleepiness, and blurred or double vision.
• Reactions affecting the stomach e.g. nausea and vomiting.
• Skin reactions e.g. rash.

The most common side effects (apart from those listed above) include:

• Decrease of white blood cells or platelets, or increase of eosinophils (a type of cell) in the blood
• Increase in certain enzymes in the liver
• Dry mouth
• Fluid retention, weight increase, low sodium in the blood

Talk to your doctor if you have any of the side effects listed above. There are a number of different side effects which are uncommon, so if you think you may have a side effect, check with your doctor or pharmacist. Often side effects such as dizziness, tiredness, headache and nausea may occur when you start taking carbamazepine but may disappear or decrease as your body gets used to the medicine.

Interactions:

Because there are many medicines which interact (or interfere) with carbamazepine, you must always tell a doctor or pharmacist if you are taking carbamazepine if you are going to take another medicine (prescribed by a doctor, or bought from a pharmacy or supermarket). Do not take anyone else's medicine - it may interfere with carbamazepine and has not been prescribed for you!

Other medicines can affect how much carbamazepine is in the body by changing the speed at which carbamazepine leaves the body or is made inactive (making this faster or slower). This is important because if there isn't quite enough carbamazepine the epilepsy (or other reason for taking carbamazepine) may not be kept under control. If you have too much carbamazepine you may get side effects such as dizziness, double-vision and lack of co-ordination. Also, some other medicines may also have some side effects that carbamazepine has, so when the two medicines are taken together there is a greater chance of that side effect occurring, and it might be worse than from either alone.

As there are many medicines that can interfere with carbamazepine, we will concentrate on a few and ask that you always talk to your doctor or pharmacist about carbamazepine when getting a prescription or buying a medicine off the shelf of a pharmacy or supermarket.

Medicines that may be available without a prescription in some countries, that may interact with carbamazepine:

• Nicotinamide (in high dosage)
• Loratadine (Claratyne)
• Cimetidine (Tagamet)
• Fluconazole (Diflucan)
• Metoclopramide (in Paramax)
• As carbamazepine may reduce alcohol tolerance it is advisable to avoid alcohol.
• Carbamazepine can reduce the effectiveness of the oral contraceptive ("the pill"), therefore if you require contraception talk to your doctor about the alternatives available.

Patient information:

• Follow the instructions on the label of the medicine or as directed by your doctor. Do not skip doses or change your dose without talking to your doctor first.
• Do not stop taking the medicine without the advice of your doctor. Stopping the medicine suddenly may possibly cause withdrawal seizures.
• If you are planning to become pregnant, talk to your doctor first as your doctor may want to change your medication in some way. The medicine will usually be given in the lowest effective dose and blood tests may be done to check the level of carbamazepine. Taking extra folic acid everyday before getting pregnant and during pregnancy is recommended to help to prevent birth defects. Use of Vitamin K1 has also been recommended for the mother during the last weeks of pregnancy as well as for the newborn. Your doctor will be able to advise you on this.
• Breastfeeding: if the mother is taking carbamazepine there will be some carbamazepine in the breast milk, and therefore if breastfeeding let the doctor know if your baby could have a reaction to carbamazepine (e.g. very sleepy, skin rash). You and your doctor will together be able to decide if breastfeeding will be best for your baby while taking carbamazepine.
• If using the syrup, shake before use.
• The tablets or syrup may be taken during, after or between meals. Tablets should be taken with liquid.
• Talk to a doctor immediately if symptoms such as fever, sore throat, skin rash, mouth ulcers, bruising or bleeding develop while you are on this medicine (and make sure the doctor knows you are taking carbamazepine).
• Carbamazepine can cause dizziness and drowsiness, particularly when first starting to take carbamazepine or if the dose is increased. In this case it may be best to avoid driving a vehicle or operating machinery.