Topamax Tablets

Generic Name: Topiramate
Product Name: Topamax Tablets

Indication

Topamax may be used to prevent migraine headaches in adults.

Topamax is used in the treatment of epilepsy in adults and in children over 2 years of age.

Topamax may be used to treat seizures in a special childhood epilepsy syndrome called Lennox-Gastaut syndrome, which sometimes causes drop attacks.

Action

Topamax prevents seizures by acting on the chemicals and nerve channels in the brain. By increasing the activity of some neurotransmitters (chemical messengers in the brain), and decreasing the activity of others, Topamax prevents the excessive electrical activity that causes epileptic fits.

It is not known exactly how Topamax helps prevent migraine headaches.

Dose advice

Topamax tablets should be swallowed whole with plenty of water. At the beginning of treatment, tablets are usually taken at night. Later in treatment, if the total dose of Topamax is greater than 50mg, the dose should be divided in two and taken as two separate doses each day.

Migraine:

Adults:

• Dosage should begin at 25mg nightly for at least one week.
• The dose may then be increased once per week by 25mg until the target dose of 50-100mg/day is reached.
• The maximum dose should not exceed 200mg/day.

When used to treat epilepsy as a single medication (monotherapy):

Adults:

• Dosage should begin at 25mg nightly for at least one week.
• The dose may then be increased once per week by 25-50mg/day until the target dose of 100mg/day is reached.
• The maximum dose should not exceed 500-1000mg/day.

Children over 2 years:

• Dosage should begin at 0.5-1mg/kg nightly for at least one week.
• The dose may then be increased once per week by 0.5-1mg/kg/day until the target dose of 3-6mg/kg/day is reached.
• The maximum dose should not exceed 500mg/day.

When used to treat epilepsy in combination with other anti-epileptic medications (‘add-on therapy’):

Adults:

• Dosage should begin at 25-50mg nightly for at least one week.
• The dose may then be increased once per week by 25-100mg/day until the target dose of 200-400mg/day is reached.
• The maximum dose should not exceed 1000mg/day.

Children over 2 years:

• Dosage should begin at 1-3mg/kg (up to 25mg/kg) nightly for at least one week.
• The dose may then be increased once per week by 1-3mg/kg/day until the target dose of 5-9mg/kg/day is reached.
• The maximum dose should not exceed 30mg/kg/day.

Topamax is a Pregnancy Category B3 drug.

Schedule

Schedule 4²

Common side effects

Common side effects, affecting more than one in ten people who take Topamax, include:

• Fatigue or sleepiness
• Headache
• Dizziness
• Confusion, memory difficulties
• Nervousness
• Paraesthesias (unusual sensations of tingling, pricking or numbness of the skin)
• Speech disorders
• Nausea, loss of appetite, or weight loss

Uncommon side effects

Uncommon (affecting less than one in ten) but important side effects of Topamax therapy include:

• Nephrolithiasis (kidney stones)
• Eye disease, including glaucoma, eye pain, or myopia (short-sightedness)
• Frequent infections caused by low levels of white blood cells (neutropenia, leucopenia)

The above side effects usually require medical treatment. Note, however, that these lists of side effects are not necessarily exhaustive. Every patient is different and you may find that Topamax causes different symptoms for you which should be discussed with your doctor. Do not be alarmed by these lists: most patients taking Topamax do not experience any side-effects at all. It is important for you to weigh up the risks and benefits of the drug (with the advice of your doctor) in your individual case to decide if this drug is suited to you.

Consult your doctor if you experience any of the above symptoms, or any other unusual or abnormal symptoms that concern you.

References

1. AMH Pty Ltd. Topiramate. Australian Medicines Handbook: January, 2007.
2. MIMS Australia Pty Ltd. Topiramate. MIMS Online 2003. Available from: http://www.mims.com.au
3. ‘Topiramate Prescribing Information’ Janssen-Cilag, 2006.
4. ‘Topiramate Consumer Medicine Information’ Janssen-Cilag, 2006.

For further information talk to your doctor.