Topiramate, an anticonvulsant antiepilepsy drug, is a sulfamate-substituted monosaccharide commonly known as Topamax. It is available as a white crystalline powder, taken orally as tablets of 25 mg, 50 mg, 100 mg, and 200 mg. It can also be opened and sprinkled on soft food and has a slight bitter taste. Hard gelatin capsules contain topiramate coated beads.

At McNeil Pharmaceutical during the research work of Joseph F. Gardocki and Brue E. Mayanoff in 1979, Topamax was discovered. Although, Ortho-McNeil Neurologics and Noramco Inc., both divisions of Johnson & Johnson produced it originally.

The chemical structure of Topamax is unlike any anticonvulsant drug. It is sulfamate- substituted monosaccharide, related to fructose.  It is most soluble in sodium hydroxide or sodium phosphate alkaline solutions and in acetone, chloroform, dimethylsulfoxide, and ethanol. 70% of the topiramate is excreted in the urine unchanged. Rest is highly metabolized by hydroxylation, hydrolysis and glucuronidation.

Topiramate is used to prevent migraine in adults, treat seizures in adults and children, 10 year olds, also in 2 year olds in combination with other medications. However, it should be kept away from the reach of the children.

Topiramate functions in body in different ways. The four properties that may add to the antiepileptic and antimigraine efficacy of topiramate are as follows. It may block voltage-dependent sodium channels, augment gamma-aminobutyrate acid activity at some subtypes of the GABA- A receptors, antagonize AMPA/kainate subtype of the glutamate receptor or inhibit carbonic anhydrase enzyme, particularly isozymes II and IV. However, the exact mechanism of action is unknown.

At doses needed to produce an anticonvulsant effect, topiramate does not induce apoptosis in young animals as is found by animal experiments. Unlike many anticonvulsants that have been associated with apoptosis in young animals, it is the only anticonvulsant that does not incite such effect.

After oral use it is quickly absorbed. Depending on the diagnosis being treated the exact dosage of topiramate is given. Dosage is increased in slow steps and initial dosage is kept low to avoid early side effects like cognitive dysfunction.  In 2 single doses, 25 to 50 mg daily is the usual initial dosage. Daily 100 to 200 mg is common dosages for maintenance treatment. 400 mg is the highest dosage recommended daily but in divided doses. However, topiramate has been used as a primary seizure medication and patients well tolerate 1600 mg per day.

Only minimal-to-moderate effects are produced by severe exposure and overdose is uncommon. Symptoms of overdose are agitation, depression, speech problems, blurred vision, double vision, troubled thinking, loss of coordination, inability to respond to things around you, loss of consciousness, pounding or irregular heartbeat, muscle weakness, bone pain, etc. But polydrug exposure can result in fatalities. Beneficial treatment is available but not an exact cure. In overdose victim’s plasma levels can range from 10–150 mg/L.

Difficulty breathing, swelling of your face, lips, tongue, throat or mood swings, depression, behavior changes, hostile attitude, agitated feeling, thoughts of hurting yourself or committing suicide are some of the possible side effects.