By Wendy C. Brooks, DVM, DipABVP
Educational Director, VeterinaryPartner.com
Brand Name: Keppra, Keppra XR, Kepcet, Kerron, Kevtan, Levitaccord, Levitam
Available in 250 mg, 500 mg, 750 mg and 1000 mg tablets, 500 mg and 750 mg extended release tablets, and oral solution (liquid)
In the search for seizure control in pets, phenobarbital and potassium bromide are the dominant medications. Unfortunately, there are pets for whom neither drug is appropriate. Phenobarbital, for example, requires extensive metabolism in the liver, can actually cause liver damage, and is associated with numerous drug interactions. Potassium bromide has been associated with pancreatitis and cannot be used in cats because it can induce inflammatory lung disease in this species.
As advances are made in seizure control in humans, medications eventually spill down into veterinary use and levetiracetam is a good example. Levetiracetam has been effective in human seizure control and has the added benefit of not being broken down by the body. (It is removed unchanged by the kidneys and thus does not pose a problem for patients with pre-existing liver diseases.) With the introduction of generics, levetiracetam became affordable for most pet owners.
Levetiracetam appears to work by interfering with release of neurochemicals that allow for communication between nerves. (It interferes with release of synaptic vesicle contents.)
How this Medication is Used
Levetiracetam can be used alone or in combination with other seizure control medications. It is usually given with other seizure control medications to boost their effectiveness. Levetiracetam is also used to allow for reduced dosing of other seizure medications in order to mitigate side effects.
An injectable form of levetiracetam is available and can be used at home to control seizures and reduce emergency clinic expenses. Traditionally this situation (unexpected seizures at home) are addressed with rectal administration of diazepam. Giving a shot under the skin might be easier to administer, especially in a seizing animal. Ask your veterinarian about this form of seizure first aid.
The chief disadvantage of levetiracetam is that it must be given three times daily in most veterinary patients. The more inconvenient a drug's dosing schedule is, the easier it is to skip doses which, in this case, could mean seizuring. The extended release formulation can be used twice daily but the tablets cannot be cut or even chewed without interfering with absorption into the body, thus they may not be an option for smaller patients. As mentioned, there is also an injectable formulation that could be useful for stopping unexpected seizures at home.
Levetiracetam can be used alone or in combination with other seizure control medications.
There are few side effects with this medication. All seizure control medications have potential to cause drowsiness. Some cats lose their appetites temporarily when beginning levetiracetam. Vomiting and diarrhea have been reported. Some cats will drool after administration.
Interactions with other Drugs
Adding levetiracetam may allow doses of other seizure control medications to be reduced. That said, there is some new information that over time, phenobarbital may "teach" the body to remove levetiracetam more quickly, possibly necessitating higher dosages to maintain the same blood levels. Further, the phenomenon of tolerance occurs with levetiracetam such that after a long time, an effective dose may simply no longer be effective as the body becomes tolerant. In this event, it may become necessary to add or change seizure medications.
Concerns and Cautions
Patients with kidney disease will need a dose adjustment as they will be less efficient at removing the drug from their bodies and higher levels may build up.
Levetiracetam is available as both regular and extended release tablets. The extended release tablets can be used for twice daily (instead of the conventional three times daily) dosing but extended release tablets must be given intact and cannot be split or crushed. This means they are only useful for appropriately sized animals.
Tolerance can develop to levetiracetam when it is used long term, which means that it will not work as well. If you think this is occurring, a new seizure medication will likely be needed.
Other seizure medications use therapeutic monitoring whereby blood levels of the drug are periodically measured to determine if the patient is in the proper range with dosing. Therapeutic levels have not been established for levetiracetam; however, some experts recommend checking levels after a patient's seizures have stabilized for a week or two so as to get the therapeutic range for that individual patient.