Following a review of in vitro study findings, the Food and Drug Administration (FDA) has issued a safety communication regarding the potential increased risk of arrhythmias in patients with heart disease who are taking lamotrigine.

Lamotrigine is indicated as monotherapy or adjunctive therapy for the treatment of epilepsy. It is also approved for use as maintenance treatment in patients with bipolar I disorder. An investigation into the drug’s effects on the heart was required after the FDA received reports of abnormal electrocardiographic findings and other serious problems (eg, chest pain, loss of consciousness, and cardiac arrest).

According to laboratory testing performed at therapeutically relevant concentrations, lamotrigine has been shown to increase the risk of serious and potentially life-threatening arrhythmias in patients with clinically important structural or functional heart disorders (eg, 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 Agency is recommending that health care professionals evaluate whether the benefits of lamotrigine outweigh the potential risk of arrhythmias for each patient.

Moreover, the concomitant use of lamotrigine with other sodium channel blockers may further increase the risk of arrhythmias. In the safety communication, the Agency stated that “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.”

Postmarketing studies are being required for other sodium channel blockers, including carbamazepine, cenobamate, eslicarbazepine, fosphenytoin, lacosamide, oxcarbazepine, phenytoin, rufinamide, topiramate, and zonisamide.


Studies show increased risk of heart rhythm problems with seizure and mental health medicine lamotrigine (Lamictal) in patients with heart disease. [press release]. Silver Springs, MD: US Food and Drug Administration; March 31, 2021.