Despite a flurry of publicity about its newfound cardiac risk profile, the antiseizure medication lamotrigine (Lamictal) is "still a good drug" in epilepsy and an excellent treatment for certain groups, New York University neurologist Jacqueline A. French, MD, told colleagues at the annual meeting of the American Epilepsy Society. But it's now crucial to take special precautions in high-risk groups such as older people and heart patients.
"We need to plan more carefully when we use it, which we hate to do, as we know. But we've still got to do it," said French, former president of the AES. "The risks are very small, but keep in mind that they're not zero."
In October 2020, the Food and Drug Administration added a warning to the lamotrigine label that said the drug "could slow ventricular conduction (widen QRS) and induce proarrhythmia, including sudden death, in patients with structural heart disease or myocardial ischemia."
The FDA recommended avoiding the sodium channel blocker's use "in patients who have cardiac conduction disorders (e.g., second- or third-degree heart block), ventricular arrhythmias, or cardiac disease or abnormality (e.g., myocardial ischemia, heart failure, structural heart disease, Brugada syndrome, or other sodium channelopathies). Concomitant use of other sodium channel blockers may increase the risk of proarrhythmia."
Later, in March 2021, the FDA announced that a review of in vitro findings "showed a potential increased risk of heart rhythm problems."
As French noted, lamotrigine remains widely prescribed even though there's "no pharmaceutical company out there pushing [it]." It's an especially beneficial drug for certain groups such as the elderly and women of child-bearing age, she said.
But older people are also at higher risk of drug-related heart complications because of the fact that many already have cardiac disease, French said. She highlighted a 2005 trial of lamotrigine that found 48% of 593 patients aged 60 years and older had cardiac disease.
So what should neurologists know about prescribing lamotrigine in light of the new warning? French recommended guidelines that she cowrote with the AES and International League Against Epilepsy.
Prescribe as normal in patients under 60 with no cardiac risk factors. In patients older than 60, or younger with risk factors, consider an EKG before prescribing lamotrigine.
"Nonspecific EKG abnormalities (e.g., nonspecific ST and T wave abnormalities) are not concerning, and should not preclude these individuals from being prescribed lamotrigine."
Beware of higher risk and consider consulting a cardiologist before starting treatment in patients with second- or third-degree heart block, Brugada syndrome, arrhythmogenic ventricular cardiomyopathy, left bundle branch block, and right bundle branch block with left anterior or posterior fascicular block.
"In most cases the initial EKG can be obtained while titrating, mainly when the individual is at the first dose of 25 mg/day because lamotrigine must be titrated slowly, and because cardiac adverse events are dose related."
"Clinicians should consider obtaining an EKG and/or cardiology consultation in people on lamotrigine with sudden-onset syncope or presyncope with loss of muscular tone without a clear vasovagal or orthostatic cause."
French cautioned colleagues that they shouldn't assume that lamotrigine stands alone among sodium channel blockers in terms of cardiac risk. As she noted, the FDA is asking manufacturers of other drugs in that class to provide data. "At some point, maybe sometime in the near future, we are going to hear in this particular in vitro sense how the other sodium channel blockers do stack up, compared with lamotrigine. At presence, in the absence of the availability of all of the rest of the data, it would be incorrect to presume that lamotrigine has more cardiac effects than other sodium channel blocking antiseizure medicines or all antiseizure medicines."
For now, she said, although the guidelines are for lamotrigine, it's "prudent" to follow them for all sodium channel blockers.
French reported no disclosures.
This article originally appeared on MDedge.com, part of the Medscape Professional Network.
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Image 1: Dr Jacqueline A. French
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Cite this: For Antiseizure Med: Don't Panic but Beware of Cardiac Risks - Medscape - Dec 20, 2021.