Compare Dilantin vs. Keppra

Head-to-head comparisons of medication uses, side effects, ratings, and more.

Dilantin (Phenytoin)

Prescription only

Keppra (levetiracetam)

Prescription only
Prevents seizures.

Dilantin (Phenytoin) is effective at preventing seizures, but has many drug interactions and side effects. If your blood tests show that you have the right amount of Dilantin (Phenytoin) levels, you’ll have a lower chance of getting side effects.

Prevents seizures.

Keppra (levetiracetam) is effective for preventing seizures in people with epilepsy and has fewer drug interactions than its alternatives.

4.5/ 5 average rating with 21 reviewsforKeppra
  • Dilantin (Phenytoin) is effective at preventing seizures, and treating seizures in an emergency.
  • Available in an oral suspension and chewable tablets if you have trouble swallowing capsules.
  • Available as a generic.
  • Keppra (levetiracetam) is effective at lowering the frequency of various types of seizures.
  • Keppra (levetiracetam) is available in liquid form or dissolving tablets if you have trouble swallowing pills.
  • Compared to other seizure medications, Keppra (levetiracetam) has fewer side effects and drug interactions, and usually does not require monitoring blood levels.
  • Need to get blood tests regularly to make sure Dilantin (Phenytoin) has safe and effective levels in your body.
  • Can cause changes in your appearance, such as unwanted hair growth, enlargement of the gums, and coarsening of your facial features.
  • If you have kidney problems, your dose and kidney function will have to be checked regularly to make sure Dilantin (Phenytoin) levels don’t get too high.
  • Can make many other medicines less effective, including birth control.
  • Must be taken on time so that there are consistent levels of the drug in your body.
  • Keppra (levetiracetam) may not be the best drug to take if you have a history of mood problems, such as depression or bipolar disorder.
  • If you have kidney problems, your dose will need to be adjusted and your doctor will check your kidney function regularly.
  • Due to its effects on your balance, Keppra (levetiracetam) may not be appropriate for the elderly.
Used for
Dosage forms
  • Extended release
  • Chewable tablet
  • Liquid
  • Pill
  • Extended release
  • Liquid
  • Oral disintegrating tablet
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21 reviews so far
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Side effects
The Dilantin (Phenytoin) FDA package insert doesn’t have numbers about how common side effects are.
13possible side effects
  • Drowsiness
  • Neck pain
  • Inflammation of the back of throat
  • Feeling off balance
  • Flu symptoms
  • Depression
  • Anxiety
  • Depressed mood
  • Double vision
  • Excessive sleepiness
  • Difficulty sleeping
  • Irritability
  • Nervousness
See more detailed side effects
Risks and risk factors
  • Skin reactions
    • People of Asian ancestry
  • Serious liver damage
    • Starting Dilantin (Phenytoin) within the first two months
  • Cardiovascular risk with fast IV infusions
    • Infusing Dilantin (Phenytoin) too fast
  • Changes in blood cells
  • Suicidal thoughts or behavior
    • History of depression
  • Bone fractures due to weakened bones
    • History of osteoporosis
    • History of fractures
  • Withdrawal seizures
    • Stopping Dilantin (Phenytoin) suddenly
See more detailed risks and warnings
  • Life-threatening skin reactions
  • Suicidal thoughts or behavior
  • Driving impairment
    • Taking with alcohol
    • Taking other medicines that make you less alert
  • Blood disorders
  • Withdrawal seizures
    • Stopping Keppra (levetiracetam) suddenly
  • Psychiatric side effects
    • History of psychiatric problems
    • Ages less than 18
See more detailed risks and warnings