Levetiracetam Side Effects: What to Expect and When to Call Your Doctor

Levetiracetam (Keppra, Keppra XR, Spritam) is generally considered one of the better-tolerated antiepileptic drugs—but that doesn't mean it's side-effect free. Understanding what to expect, and which symptoms signal a serious problem, helps you use this medication safely and confidently.

Most Common Side Effects of Levetiracetam

The most common side effects in adults are somnolence (drowsiness), asthenia (weakness), and dizziness. In clinical trials, headache occurred in about 14% of patients, and somnolence in about 14% as well. These typically occur within the first 4 weeks of treatment:

• Sleepiness / somnolence: The most commonly reported side effect. Usually improves with time. Avoid driving or operating machinery until you know how levetiracetam affects your alertness.
• Weakness / fatigue: General tiredness and muscle weakness. Often improves within the first few months.
• Dizziness: Less common than drowsiness but can affect balance and coordination.
• Headache: Common, especially early in treatment. Over-the-counter analgesics can help, but consult your pharmacist about interactions.
• Nasopharyngitis / infection: Upper respiratory infection rates were slightly higher in clinical trial participants on levetiracetam.

The "Keppra Rage": Behavioral Side Effects

One of the most discussed aspects of levetiracetam is its effect on mood and behavior—sometimes called "Keppra rage" by patients and caregivers. This isn't a medical term, but it refers to real, documented side effects that affect a meaningful subset of patients:

• Irritability, aggression, and anger outbursts
• Anxiety, agitation, and restlessness
• Mood swings and emotional lability
• Depression and low mood

These effects occur in approximately 5–15% of patients and are more common in children and adolescents. They tend to be dose-dependent and may improve with dose reduction. If behavioral side effects are affecting your quality of life, talk to your neurologist—switching to brivaracetam (Briviact), which has the same mechanism but fewer behavioral effects, is an option for some patients.

Pediatric Side Effects

Children on levetiracetam have a somewhat different side effect profile than adults. The most commonly reported side effects in children include:

• Fatigue and somnolence
• Aggression and behavioral problems
• Nasal congestion
• Decreased appetite
• Irritability

Serious Side Effects: Call Your Doctor Right Away

While uncommon, levetiracetam can cause serious and potentially life-threatening reactions. Seek immediate medical attention for:

• DRESS (Drug Reaction with Eosinophilia and Systemic Symptoms): Typically begins as a rash 2–8 weeks after starting levetiracetam, then progresses to involve internal organs (liver, kidneys, heart). Can be fatal if not treated promptly. In December 2023, the FDA issued a specific safety alert about this risk.
• Stevens-Johnson syndrome (SJS) / Toxic Epidermal Necrolysis (TEN): Rare but serious skin reactions causing blistering and skin peeling. Painful red or purple rash that spreads; skin may peel off in sheets. Emergency situation.
• Suicidal thoughts or behavior: All antiepileptic drugs carry an FDA warning about increased risk of suicidal thoughts. Seek help immediately if you or a family member experiences new or worsening depression, thoughts of self-harm, or unusual mood changes.
• Anaphylaxis / severe allergic reaction: Sudden swelling of face, lips, tongue, or throat; difficulty breathing; hives. Call 911.
• Psychosis: About 1% of adults and 2% of children in clinical trials experienced psychotic symptoms (paranoia, hallucinations). Contact your prescriber immediately.
• Blood disorders: Levetiracetam can rarely cause low white blood cell counts (leukopenia), anemia, or neutropenia. Report unusual bruising, bleeding, or signs of infection.

Do Not Stop Levetiracetam Without Medical Guidance

If you experience side effects, talk to your doctor before stopping levetiracetam. Abrupt discontinuation can trigger withdrawal seizures. Your doctor may recommend a gradual dose taper or a switch to an alternative medication. Never stop on your own.

Need help filling your levetiracetam prescription? Use medfinder to find pharmacies near you with it in stock. Also read: Levetiracetam Drug Interactions.