Prediction: Anticonvulsant Suicide Warnings Unlikely to Affect Prescriptions

While the FDA considers whether to add suicide warnings to the labels of 11 epilepsy drugs,* the measure is unlikely to affect prescriptions—at least by neurologists. That's because the cost of nonadherence to anticonvulsant therapy among epileptic patients is known to be so high.

For example, in this week's print issue of Neurology, investigators report a 3-fold increased risk of death among nonadherent epileptic patients in a retrospective study of Medicaid claims from Florida, Iowa, and New Jersey (N = 33,658).** Nonadherence, determined by non-possession of medication, was also associated with significantly more ER visits (50% increased risk), hospital admissions (86%), car accidents (108%), and bone fractures (21%).

In the FDA's assessment of 199 placebo-controlled studies of patients with epilepsy, selected psychiatric illnesses, or pain conditions (N = 43,892), there were only 4 (0.009%) suicides in drug-treated patients and none in placebo-treated individuals. Suicidal behavior or ideation was reported in 0.37% of patients who received an anticonvulsant and in 0.22% of those who received placebo. While the risk of suicidality is almost 70% higher with anticonvulsant treatment, the absolute risk remains small at 0.15%. Not surprising, the risk of suicidality with either drug treatment or placebo was lower in epileptic patients than in psychiatric patients (see table).

The FDA is holding a public advisory meeting on the risk of suicide with anticonvulsant drugs on July 10.

Photo: iStockPhoto.

*The 11 drugs are carbamazepine (Carbatrol; Shire); felbamate (Felbatol; Meda); gabapentin (Neurontin; Pfizer), lamotrigine (Lamictal; GSK); levetiracetam (Keppra; UCB); oxcarbazepine (Trileptal; Novartis); pregabaline (Lyrica; Pfizer); tiagabine (Gabitril; Cephalon); topiramate (Topamax; Ortho-McNeil); valproate (Depakote; Abbott); and zonisamide (Zonegran; Eisai).

**The study was sponsored by GSK, maker of Lamictal (lamotrigine). One of the study authors is an employee of GSK, and the other authors report support from GSK, in the form of research grants and/or "other activities."