Following a first seizure, physicians should discuss with patients whether it is appropriate to prescribe medication to reduce risk of another seizure, according to new guidelines released at the American Academy of Neurology meeting.

The guidelines, which were a collaboration of authors at several North American medical institutions, including NYU Langone Medical Center, found adults who experience a first seizure may have risk of another seizure that’s greatest within the first two years. Adults with prior neurological trauma or abnormalities on EEGs and imaging may be at a greater risk.

The authors found moderate evidence that immediate treatment with an epilepsy drug can reduce risk of recurrent seizures within two years of the initial episode. However, they also found moderate evidence that after more than three years, immediate treatment with an epilepsy drug is unlikely to improve the chances of remaining seizure-free, compared with waiting for another seizure to occur before treating.

The guidelines were jointly released by the American Academy of Neurology and American Epilepsy Society.

These guidelines do not definitively state that a patient should immediately start taking medication if they present with a first seizure, explains senior study author Jacqueline French, MD, a professor of neurology and director of translational research at NYU Langone’s Comprehensive Epilepsy Center in New York City. What the new guidelines do is provide a blueprint to prompt physicians to have an important conversation with their patients to discuss the risks and benefits of starting treatment following a first seizure.

“Millions of people experience a seizure for the first time each year, potentially raising risk for recurrent seizures, neurological trauma and other psychological and physical challenges. These guidelines enable doctors and patients to take a step back and discuss whether to begin treatment with medication, weighing the individual patient’s risks and benefits with the latest evidence-based research,” says Dr. French, who is also Chief Scientific Officer of the Epilepsy Foundation.

Researchers systematically reviewed nearly 50 studies on first seizure that addressed the probability that an adult with an unprovoked first seizure would have recurrent seizures, in addition to information about short and long-term health risks and medication side effects.

According to the guidelines, there is strong evidence that adults who have had a first seizure have between a 21 and 45 percent risk of another seizure that’s greatest within the first two years. The researchers also found strong evidence that the risk of a second seizure is greatest in people with a previous brain trauma, such as from a head injury, stroke or tumor, and in those who showed EEG abnormalities that might suggest epilepsy. The authors found moderate evidence that seizure recurrence risk is greatest in people with a significant abnormality on brain imaging scans and in those who have nocturnal seizures during sleep.

For medication management, the guidelines show moderate evidence that immediate treatment with an epilepsy drug can reduce risk of a second seizure within two years. However, the authors also found moderate evidence that after more than three years, immediate treatment with an epilepsy drug is unlikely to improve the chances of remaining seizure-free, compared with monitoring and treating after another seizure.

The guidelines also note that in addition to affecting lifestyle choices, such as the ability to drive a car, epilepsy drugs carry risks of side effects ranging from seven to 31 percent. “This is a valuable new guideline that could change the approach many doctors take to treating a first seizure and could improve patients’ lives,” says guidelines first author Allan Krumholz, MD, a professor of neurology at the University of Maryland School of Medicine.

About one in 10 people worldwide–including 150,000 Americans–will experience a first seizure in their lifetime. Epilepsy is a disease characterized by one or more unprovoked seizures with a high likelihood of recurrence that are not due to another immediate triggering cause. Epilepsy affects between 2.2 and 3 million Americans, according to the American Epilepsy Society.

The guideline is published in the April 21, 2015, print issue of Neurology and will be presented at a press conference on April 20, 2015 at the American Academy of Neurology’s Annual Meeting in Washington, DC.

In addition to Drs. French and Krumholz, the authors of the guidelines were: Samuel Wiebe, MD, Gary S. Gronseth, MD, David S. Gloss, MD, Ana M. Sanchez, MD, Arif A. Kabir, MD, Aisha T. Liferidge, MD, Justin P. Martello, MD, Andres M. Kanner, MD, Shlomo Shinnar, MD, PhD, and Jennifer L. Hopp, MD.