Monitoring Epileptic Patients

Pets diagnosed with epilepsy are usually prescribed one or more medications to prevent convulsions or seizures. These medicines, called anticonvulsants, are often needed long-term and in many cases are used for the life of the pet. Careful monitoring of epileptic pets is necessary to make sure the dose of the medication is right and also to ensure there are no problems related to long-term use of the medication.

What is involved in monitoring my epileptic pet?

Monitoring your epileptic pet involves a series of blood tests that measure the level of anticonvulsant medication in the bloodstream. If a blood test indicates the dose of medication is too high or too low, your veterinarian will adjust the dose. After a trial period at the new dose, a follow-up test will be done to see if further adjustment is needed. 

The objective is to maintain blood levels of medication within specific limits, called the therapeutic range. If your pet’s blood level is within this range, then it is expected the seizures will be controlled. If blood levels are below the therapeutic range, then it is more likely that your pet’s seizures will continue.

The timing of the monitoring tests may be important in some situations. For example, it may be helpful to know the highest (peak) or lowest (trough) blood level of medication achieved with a certain dosage of anticonvulsant. These peak and trough values occur at specific intervals after medication is given, and they are different for various medications. Your veterinarian will let you know if timed testing is needed and what schedule you should follow.

How many blood tests are needed?

Frequent blood testing is often needed in a newly diagnosed epileptic pet to get the dose of anticonvulsant just right. Once the correct dose has been established and your pet appears stable, then testing may drop to every three to six months. Your veterinarian will advise you about the best schedule for your pet.

How long will it take my pet to stabilize on anticonvulsant medication?

During the initial period of medication, blood levels of anticonvulsant gradually rise and eventually reach a steady state. The time needed to stabilize a pet varies both with the individual animal and the specific anticonvulsant being used. Some medications require a few weeks to achieve equilibrium, while others may take months. During this initial period, adjustments to the dosage need to be made carefully and should be made only by your veterinarian.

Are other blood tests required?

In addition to monitoring blood levels of anticonvulsant, periodic wellness testing may be recommended. Wellness testing involves a panel of blood tests that help assess your pet’s overall health and determines if the anticonvulsant medication is causing side effects elsewhere in the body (e.g., liver). Wellness Testing is especially important for pets that have been on long-term anticonvulsant therapy. See handouts “Wellness Testing for Cats" and "Wellness Testing for Dogs" for more information.

What should I be watching for now that my pet is on medication?

The most important thing to report to your veterinarian is a seizure. If your pet has a seizure while on the medication it may indicate that the dose of medication is not high enough or the interval between doses needs to be adjusted. Your veterinarian may also want to add or change medications.

Other things to watch for include severe drowsiness, staggering, lethargy, lack of energy, vomiting, and loss of appetite. These signs may indicate the level of medication is too high or that complications have developed elsewhere in the body. Notify your veterinarian promptly.

How should I prepare my pet for blood testing?

• The most important thing to do is follow your veterinarian's instructions closely and give your pet the prescribed medication regularly and consistently, which will ensure the value reported on the blood test is reliable.
• If timed testing is needed, be sure to give the medication at the proper time. Also notify the receptionist so the proper appointment time can be booked for you.

As for any blood test, withholding food for 4–6 hours before blood collection often results in a better-quality sample. Water is permitted.