A number of factors affect a topiramate dose, including the condition for which it is being used, whether it is being used alone or in combination with other antiepileptic medicines and the patient’s tolerance and response. Topiramate may be used to treat epilepsy and as a migraine prophylaxis and is normally available by prescription only. It may be known by different trade names in different countries, according to manufacturer.
Topiramate works via a number of mechanisms in the treatment of epilepsy. The first is that it blocks sodium, which is a chemical involved in electrical impulses in the brain which may cause seizures. Secondly, it increases the action of GABA, a neurotransmitter which has a calming effect and thirdly, it blocks glutamate receptors. Glutamate is another neurotransmitter which causes excitement of the nerve cells in the brain. The mechanism by which it works to prevent attacks of migraine is not known.
When establishing the sufficient topiramate dose, the treating doctor will usually start with a low dose and work it up slowly, increasing at weekly intervals until the desired response is obtained. Initially the topiramate dose may be taken once a day, at night, but generally, once a maintenance dose has been established, it will be taken twice daily. When used in combination with other antiepileptic drugs as an adjunctive therapy, the dose may be lower.
In children, the sufficient topiramate dose is established by the weight of the child and titration up to a maintenance dose will also be done. Topiramate dose adjustments may be recommended in elderly patients and those with liver or kidney dysfunction. If withdrawing off topiramate, it should be done under supervision of a doctor and withdrawn slowly, to minimize the chance of withdrawal.
When using the drug for migraine prophylaxis, that is the prevention of migraine attacks, the topiramate dose is usually 100 mg a day taken as 50mg twice daily. Again, the drug will be started at a low dose and increased on a weekly basis with the treating doctor monitoring both response and tolerance. The lowest effective dose will be prescribed.
As with any medication, regardless of the topiramate dose used, it may be contraindicated in patients with some underlying clinical conditions and may interact with other medications, including complementary, over-the-counter and homeopathic medicines. These should all be discussed with the prescribing doctor before starting treatment with topiramate, as should pregnancy, desired pregnancy and lactation.