Topiramate: uses, contraception and cautions

Topiramate has two licensed uses, according to the NHS: treating seizures in epilepsy and preventing migraine. It is a preventer, so it is taken regularly whether or not you have a seizure or an attack that day. It is prescription-only, and Topamax is the brand name on the NHS page.

In epilepsy the NHS says it works by blocking the signals in the brain that can cause seizures. For migraine it calms overactive nerve cells that can trigger attacks, which is why a medicine developed for epilepsy can reduce migraines.

Topiramate comes as tablets, capsules and a liquid. The doctor tells you when and how much to take; the NHS does not print a standard dose. A low start with slow increases over weeks is typical, which also helps the body adapt.

It is taken twice a day at consistent times. Tablets and capsules are swallowed whole with water, although capsules can be opened and sprinkled on soft food if swallowing is hard. The liquid is measured with the device supplied.

If you miss a dose, take it straight away unless the next one is near, and then skip it. Never double up. Taking an extra amount is unlikely to cause problems on its own, but it can sometimes be dangerous, so ask a pharmacist or use NHS 111, and go to A&E if told to.

The NHS lists feeling sick, dizziness, tiredness, diarrhoea, loss of appetite or weight loss, tremor and low mood as common. Most ease within a couple of weeks as the body adjusts. If you are drowsy or dizzy after a dose, avoid driving or using machinery.

Three serious categories are named: anaphylaxis (swollen throat or tongue, itchy rash, difficulty breathing), serious skin reactions such as erythema multiforme, Stevens-Johnson syndrome (painful blisters) or peeling skin, and metabolic acidosis, meaning too much acid in the blood, which can show as sleepiness, loss of appetite and an irregular heartbeat. The NHS says to call 999 for anaphylaxis or Stevens-Johnson syndrome and NHS 111 for other serious effects.

Low mood appears on the list of common effects, so a change in mood should be raised with the prescriber and not put up with. Reports of suspected side effects can be made through Yellow Card.

Before starting, the doctor checks for conditions that make topiramate unsuitable or need extra care.

• Kidney or liver problems.

• Glaucoma.

• A previous allergic reaction to topiramate.

• Pregnancy, or trying to conceive, because of the birth-defect risk described below.

This is the section to read carefully. The NHS says topiramate has been linked to a risk of birth defects if taken during pregnancy, and that you must use contraception while taking it if there is a chance you could get pregnant, continuing for at least 1 month after stopping.

Doctors usually recommend switching to another medicine in pregnancy. The exception noted is epilepsy, where continued use may be allowed only if other seizure medicines have not worked and the benefit outweighs the risk. Combined hormonal methods such as the pill may be less effective with topiramate, so alternatives such as condoms are often suggested.

For breastfeeding, tell the doctor before using topiramate; they will weigh whether the benefits to you outweigh the risks to the baby.

The NHS names hormonal contraceptives and other epilepsy medicines as the main interaction groups, so a full medicines list should be shared with the prescriber and pharmacist. On alcohol, it is best avoided, as it may increase side effects or the chance of a seizure.

Driving is not advised when you feel tired or dizzy. Epilepsy has additional legal driving rules covered on this site.

Keep taking topiramate for as long as the doctor advises, and expect the dose to be reduced gradually when treatment ends. The NHS recommends annual reviews for women taking it for epilepsy.

Alternatives depend on whether it is being used for epilepsy or migraine. The guides on migraine and on epilepsy medication choices outline the wider options without recommending any for you.