THERAPEUTICS

Brands

• Topamax, Topamax Sprinkle, Trokendi XR, Qudexy XR

Generic?

• Yes

Class

• Antiepileptic drug (AED)

Commonly Prescribed for

(FDA approved in bold)

• Partial-onset seizures (adjunctive; adults and pediatric patients age 2–16)

• Primary generalized tonic-clonic seizures (adjunctive; adults and pediatric patients age 2–16)

• Lennox-Gastaut syndrome adjunctive therapy (age > 2)

• Migraine prophylaxis (Topamax only)

• Cluster headache prophylaxis

• Myoclonic epilepsy

• Neuralgia/neuropathic pain

• Drop attacks associated with Lennox- Gastaut syndrome

• Obesity

• Bipolar disorder

• Binge-eating disorder/bulimia

• Idiopathic intracranial hypertension

• Alcohol dependence

• Essential tremor

• Phantom limb pain

How the Drug Works

There are multiple mechanisms of action, and it is uncertain which of these give the drug its effectiveness

• Augments the GABAA1 receptor

• Blocks voltage-dependent sodium and calcium (N-type) channels

• Antagonizes the glutamate receptor (AMPA/ kainate subtype)

• Inhibits carbonic anhydrase (isoenzymes II and IV)

• May inhibit protein kinase activity

• Possible serotonin activity on 5-HT2C receptor

How Long Until It Works

• Seizures: may decrease by 2 weeks

• Migraines: may decrease in as little as 2 weeks, but can take up to 3 months on a stable dose to see full effect

If It Works

• Seizures: goal is the remission of seizures. Continue as long as effective and well tolerated. Consider tapering slowly, stopping after 2 years without seizures, depending on the type of epilepsy

• Migraine: goal is a 50% or greater reduction in migraine disability. Consider tapering or stopping if headaches remit for more than 6 months or if considering pregnancy

If It Doesn't Work

• Increase to highest tolerated dose

• Epilepsy: consider changing to another agent, adding a second agent, using a medical device, or a referral for epilepsy surgery evaluation. When adding a second agent, keep drug interactions in mind

• Migraine: address other issues, such as medication overuse, other coexisting medical disorders, such as anxiety, and consider changing to another agent or adding a second agent