USA: People with heart disease taking the seizure and bipolar disorder drug lamotrigine (Lamictal) may be at increased risk of heart rhythm problems called arrhythmias, warns FDA.
Lamictal (lamotrigine, GlaxoSmithKline) is used alone or in combination with other agents to treat seizures in patients aged 2 years and older. It may also be used as maintenance treatment in patients with the mental health condition bipolar disorder to help delay the occurrence of mood episodes such as depression, mania, or hypomania.
The US Food and Drug Administration wants to evaluate whether other medicines in the same drug class have similar effects on the heart and are also requiring safety studies on those medicines. FDA will update the public when additional information from these studies becomes available.
The warning follows a review of in vitro data of lamotrigine conducted after cases of abnormal electrocardiographs, cardiac arrest, loss of consciousness, and other adverse events were reported. Updates to the drug's prescribing information and medication guides were made in late 2020.
Recommendations include:
Patients should not stop taking your medicine without first talking to your prescriber because stopping lamotrigine can lead to uncontrolled seizures, or new or worsening mental health problems. Contact your health care professional right away or go to an emergency room if you experience an abnormal heart rate or irregular rhythm, or symptoms such as a racing heartbeat, skipped or slow heartbeat, shortness of breath, dizziness, or fainting.
Health care professionals should assess whether the potential benefits of lamotrigine outweigh the potential risk of arrhythmias for each patient. Laboratory testing performed at therapeutically relevant concentrations has shown that lamotrigine can increase the risk of serious arrhythmias, which can be life-threatening in patients with clinically important structural or functional heart disorders.
Clinically important structural and functional heart disorders include heart failure, valvular heart disease, congenital heart disease, conduction system disease, ventricular arrhythmias, cardiac channelopathies such as Brugada syndrome, clinically important ischemic heart disease, or multiple risk factors for coronary artery disease.
The risk of arrhythmias may increase further if used in combination with other medicines that block sodium channels in the heart. Other sodium channel blockers approved for epilepsy, bipolar disorder, and other indications should not be considered safer alternatives to lamotrigine in the absence of additional information.
Health professionals and patients are encouraged to report adverse events or side effects related to the use of these products to the FDA's MedWatch Safety Information and Adverse Event Reporting Program.
Reference:
FDA drug safety communication