Topirva

Indications

Topiramate is used to:

• Treat epilepsy: focal (partial) seizures and generalised tonic-clonic seizures, alone or with other epilepsy medicines, in adults and children; also as add-on treatment for seizures linked to Lennox-Gastaut syndrome
• Prevent migraine headaches in adults (it does not treat a migraine that has already started)

How It Works

Topiramate calms overactive nerve signals in the brain. It blocks some sodium channels, boosts the calming chemical GABA and reduces the effect of the excitatory chemical glutamate. This lowers the chance of seizures and migraine attacks.

Dosage and Administration

The dose is started low and increased slowly over several weeks to reduce side effects. Take exactly as prescribed.

• Epilepsy, adults: often started at 25 mg at night and increased weekly or every two weeks. The usual maintenance dose is 100 to 200 mg a day in two divided doses, as prescribed.
• Migraine prevention, adults: usually started at 25 mg at night and increased weekly by 25 mg. The usual dose is 50 to 100 mg a day in two divided doses.
• Children: dose is based on body weight, as prescribed.

Swallow tablets whole with water, with or without food. Drink plenty of fluids every day to help prevent kidney stones. Do not stop suddenly; the dose is reduced gradually.

Interactions

• Carbamazepine and Phenytoin can lower Topiramate levels; Topiramate may raise Phenytoin levels.
• With Valproic acid, there is a risk of high ammonia (confusion, drowsiness) and low body temperature.
• It can make oestrogen-containing contraceptive pills less effective, especially at higher doses. Discuss reliable contraception with the doctor.
• Alcohol and other medicines that cause drowsiness add to sleepiness and dizziness.
• Acetazolamide and Zonisamide raise the risk of kidney stones and acid build-up in the blood.
• It may change levels of Lithium, Metformin and Hydrochlorothiazide.

Contraindications

• Allergy to Topiramate
• Migraine prevention during pregnancy, or in women who could become pregnant and are not using highly effective contraception

Side Effects

Common: tingling in the hands and feet, tiredness, dizziness, loss of appetite and weight loss, trouble concentrating, memory problems, difficulty finding words, slowed thinking, changes in taste, nausea, diarrhoea and mood changes.

Get urgent medical help if you notice:

• Sudden blurred vision, eye pain or red eyes (possible acute glaucoma)
• Severe pain in the back or side, or blood in the urine (possible kidney stone)
• Reduced sweating with high body temperature, especially in children in hot weather
• Thoughts of harming yourself, or new or worsening depression or anxiety
• Fast breathing, unusual tiredness or confusion (possible acid build-up in the blood)
• A severe skin rash with blisters or peeling

Pregnancy and Lactation

Topiramate can harm an unborn baby, including a higher risk of cleft lip and palate and of a baby being small for its age. Women who could become pregnant should discuss highly effective contraception with the doctor. For epilepsy, do not stop the medicine suddenly if you become pregnant; see the doctor urgently to review treatment. It must not be used for migraine prevention in pregnancy. It passes into breast milk; the doctor will advise whether to breastfeed, and the baby should be watched for drowsiness, diarrhoea or poor feeding.

Precautions and Warnings

• Do not stop suddenly, as this can trigger seizures.
• Drink plenty of water to lower the risk of kidney stones.
• Tell the doctor about kidney or liver disease, or a history of kidney stones.
• It can cause drowsiness and slowed thinking; do not drive until you know how it affects you.
• Watch for mood changes; family members should report these to the doctor.
• Children's growth and weight may be monitored.

Overdose

Symptoms may include seizures, severe drowsiness, slurred speech, blurred vision, low blood pressure, stomach pain, confusion and severe acid build-up in the blood. Get emergency medical help straight away.

Therapeutic Class

Anticonvulsant (antiepileptic); also used for migraine prevention.

Storage

Store below 30°C in a dry place, away from light and out of the reach of children.