Megan Brooks
November 28, 2023

The antiseizure drugs levetiracetam (Keppra, Keppra XR, Elepsia XR, Spritam, generic) and clobazam (Onfi, Sympazan, generic) can cause a rare but serious drug hypersensitivity reaction that can be life threatening if not detected and treated promptly, the US Food and Drug Administration (FDA) warns in an alert issued today.

Known as drug reaction with eosinophilia and systemic symptoms (DRESS), it may start as a rash but can quickly progress and cause injury to internal organs, the need for hospitalization, and death, the FDA notes.

A search of the FDA Adverse Event Reporting System (FAERS) and the medical literature through March 2023 identified 32 serious cases of DRESS worldwide that were associated with levetiracetam.

Three cases occurred in the US, and 29 occurred abroad. In all 32 cases, the patients were hospitalized and received medical treatment; in two cases, the patients died.

The median time to onset of DRESS in the levetiracetam cases was 24 days; times ranged from 7 to 170 days. The reported signs and symptoms included skin rash (n = 22), fever (n = 20), eosinophilia (n = 17), lymph node swelling (n = 9), and atypical lymphocytes (n = 4).

Twenty-two levetiracetam-associated cases of DRESS involved injury to one or more organs, including the liver, lungs, kidneys, and gallbladder.

In 25 of the 29 cases for which information on treatment discontinuation was available, DRESS symptoms resolved when levetiracetam was discontinued.

As for clobazam, a search of FAERS and the medical literature through July 2023 identified 10 serious cases of DRESS worldwide ― one in the US, and nine abroad. All 10 patients were hospitalized and received medical treatment. No deaths were reported.

The median time to onset of clobazam-associated DRESS was 21.5 days (range, 7 to 103 days). The reported signs and symptoms included skin rash (n = 10), fever (n = 8), eosinophilia (n = 7), facial swelling (n = 7), leukocytosis (n = 4), lymph node swelling (n = 4), and leukopenia/thrombocytopenia (n = 1).

In nine cases, there was injury to one or more organs, including the liver, kidneys, and gastrointestinal tract.

DRESS symptoms resolved in all 10 cases when treatment with clobazam was stopped. DRESS and other serious skin reactions reported with clobazam, a benzodiazepine, have not generally been associated with other benzodiazepines, the FDA notes.

Label Updates

As a result of these cases, warnings about the risk of DRESS will be added to the prescribing information and patient medication guides for these medicines, the FDA announced.

“Health care professionals should be aware that prompt recognition and early treatment is important for improving DRESS outcomes and decreasing mortality,” the FDA said.

They note that diagnosis is often difficult because early signs and symptoms, such as fever and swollen lymph nodes, may be present without evidence of a rash.

DRESS may develop 2 to 8 weeks after starting levetiracetam or clobazam. Symptoms and intensity can vary widely.

DRESS can also be confused with other serious skin reactions, such as Stevens-Johnson syndrome and toxic epidermal necrolysis.

The FDA says patients should be advised of the signs and symptoms of DRESS and be told to stop taking the medicine and seek immediate medical attention if DRESS is suspected during treatment with levetiracetam or clobazam.

Adverse reactions with these medications should be reported to the FDA’s MedWatch program.


Source: FDA Warns of Potentially Lethal Reaction to Seizure Meds – Medscape – Nov 28, 2023.