New safety warning for lamotrigine highlights risk of arrhythmias

The potential cardiac effects of lamotrigine were added to its label late last year, and in March 2021, FDA released a drug safety communication highlighting the increased risk arrhythmias patients with heart disease who use lamotrigine. Data from vitro testing showed that exhibits Class IB antiarrhythmic activity at therapeutically relevant concentrations. In people structural or myocardial ischemia, medication could slow ventricular conduction increase arrythmia, agency warned. “It was bit confusing this new warning seemed be based entirely on data, not any clinical signal,” said Barry Gidal, PharmD, FAES, professor pharmacy University Wisconsin Madison Neurology Today article. “Fairly quickly, it became obvious there growing level concern generated by epilepsy community. Several specialists they getting questions concerned looking for guidance.” requested data after receiving reports abnormal electrocardiographs, arrest, loss consciousness, other adverse events drug. recommends clinicians evaluate whether benefits outweigh risks arrythmias each patient, especially those underlying issues. It also advises stop taking without first discussing their prescriber, seek medical help if experience symptoms such as an rate, shortness breath, dizziness, fainting. is evaluating sodium channel blockers, carbamazepine, phenytoin, topiramate, have similar requiring studies medications. interim, blockers should considered safer alternatives additional information these agents, said. response update, International League Against Epilepsy (ILAE) American Society (AES) formed advisory task force advise health care professionals how minimize associated advisory, noted although indicate has 1B blocking properties, no change been observed (i.e., QRS conduction) QT does prolong repolarization) healthy individuals disease. On basis, determined “there apparent arrhythmia therapy disease.” offers guidance electrocardiogram (ECG) monitoring use. undiagnosed asymptomatic under age 60 minimal absence major cardiovascular factors, stated, over 60, ECG may before initiating An known significant factors. Nonspecific abnormalities (e.g., nonspecific ST T wave abnormalities) are concerning preclude being prescribed lamotrigine, wrote. For findings pose greatest second third-degree block, left right bundle branch block), thorough cardiological investigation determine can administered safely. comments when obtain initial repeat ECGs. Clinicians aware carefully treatment patients. Since current limited vitro), conditions needed, along blockers.