drugs

Zonegran - zonisamide

What is Zonegran?

Zonegran is a medicine containing the active substance zonisamide. It is available in white (25 mg), white and gray (50 mg), and white and red (100 mg) capsules.

What is Zonegran used for?

Zonegran is indicated as an adjunctive therapy in the treatment of adult patients with partial epileptic seizures (seizures that originate in a precise part of the brain). It can be used in patients with or without secondary generalization (secondary generalization occurs when hyperactivity expands subsequently to the entire brain area).

The medicine can only be obtained with a prescription.

How is Zonegran used?

Zonegran must be added to existing therapy. The recommended starting dose is 25 mg twice a day, taken with or without food. After one week the dose can be increased up to 100 mg a day and then the dose can be increased at weekly intervals in increments up to 100 mg, depending on the patient's response. Once the most appropriate dosage is established, Zonegran can be given once or twice a day. Doses of 300 to 500 mg a day have been shown to be effective, but lower doses may be sufficient for some patients. The maximum daily dose is 500 mg.

In patients with disorders of the liver or kidneys or in subjects taking certain other drugs it may be necessary to increase the dose less frequently. Zonegran should be used with caution in elderly patients and those with kidney problems. Use of the medicine in patients with severe hepatic impairment is not recommended. Before stopping Zonegran it is necessary to gradually reduce the dose.

For more information, see the summary of product characteristics, also included with the EPAR.

How does Zonegran work?

The active substance in Zonegran, zonisamide, is an anti-epileptic. Epileptic seizures are caused by abnormal electrical activity in the brain. Zonisamide works by blocking certain pores located on the surface of nerve cells and called sodium channels and calcium channels. These channels transmit electrical impulses from one nerve cell to another. By blocking these channels, zonisamide prevents nerve cells from synchronizing their activity and from abnormal electrical activity to spread to other parts of the brain. This reduces the chances of an epileptic seizure occurring. Zonegran also acts on the neurotransmitter called gamma-aminobutyric acid (GABA), a chemical that allows nerve cells to communicate with each other. This can help stabilize the electrical activity of the brain.

What studies have been carried out on Zonegran?

The applicant presented data on experimental models from the scientific literature.

Zonegran was examined as an adjunctive therapy in an important study involving 351 patients with partial seizures. In this study the effects of Zonegran were compared with those of placebo (a dummy treatment). The dose of Zonegran was gradually increased over a six-week period, then maintained stable for a period of 18 weeks. The main measure of effectiveness was the change in the frequency of partial seizures in the period between 12 weeks prior to the start of therapy and the 18-week treatment period with the fixed dose.

What benefit has Zonegran shown during the studies?

Zonegran was more effective than placebo in reducing the frequency of attacks. Patients treated with 500 mg of Zonegran daily experienced a mean crisis frequency reduction of 51% compared to 16% of patients treated with placebo.

What is the risk associated with Zonegran?

The most commonly reported side effects with Zonegran (seen in more than 1 patient in 10) are anorexia (severe decrease or disappearance of appetite), agitation, irritability, confusion, depression, ataxia (lack of muscle coordination), dizziness, deficit of memory, drowsiness, diplopia (split vision) and lower levels of bicarbonate in the blood. Severe skin rashes have been observed in patients taking Zonegran, including cases of Stevens-Johnson syndrome (an acute, life-threatening type of allergic reaction). For the full list of all side effects reported with Zonegran, see the Package Leaflet.

Zonegran should not be used in people who may be hypersensitive (allergic) to zonisamide, to any of the other ingredients or to sulfonamides (such as some antibiotics).

Why has Zonegran been approved?

The Committee for Medicinal Products for Human Use (CHMP) decided that Zonegran's benefits are greater than its risks as an adjunctive treatment in the treatment of adult patients with partial seizures, with or without secondary generalization, and therefore recommended the release of product marketing authorization.

More information on Zonegran:

On 10 March 2005, the European Commission issued a marketing authorization valid for Zonegran, valid throughout the European Union, to Eisai Limited.

For the full EPAR for Zonegran, click here.

Last update of this summary: 04-2008