If your cat has recently been diagnosed as having epilepsy you may be concerned about the future. Discuss your concerns with your vet – it is important that you fully understand the goals of treatment right from the start.
Epileptic animals are born with the condition and cannot be cured. The aim of treatment is to ‘control’ their seizures. Whilst anti-epileptic drugs will make some animals seizure-free, for most treatment is judged to be successful if the frequency and severity of the seizures is reduced with few side-effects. You must understand that, if your cat is epileptic, they are likely to continue to have some seizures despite being on treatment. It is not possible to achieve seizure control in some cats despite adequate therapy.
Once treatment for epilepsy starts it is likely to be continued lifelong. Many cats only have a single seizure episode, and so it is not sensible to put all these animals on permanent treatment (when many would not have another seizure anyway). Some vets recommend starting treatment of seizures after a second seizure episode. Other vets are more cautious and like to balance the benefits of treatment with its potential adverse effects.
You should consider treatment for your pet if:
- They are having more than one seizure a month and/or you find the frequency distressing
- They have a very severe seizure or cluster of seizures, whatever the frequency
- Their seizures are increasing in frequency or severity
- Underlying brain disease has been identified as the cause of the seizures
Many drugs used in people with epilepsy are either toxic to pets or are removed from the body so quickly that good ‘control’ of seizures cannot be achieved. The first treatment in cats is usually either phenobarbitone, diazepam (ValiumR), gabapentin (NeurotinR) or levetiracetam (KeppraR).
Individual animals respond in different ways to anti-epileptic treatment. It is not the number of tablets given that is important but the level of drug in the body. The blood level of drug determines not only the good effects (also known as therapeutic effects) but also the toxic effects. Blood levels of phenobarbitone can be measured to ensure that they are within a certain range (therapeutic range) that controls seizures with minimal side-effects.
A blood test can help your vet decide whether your cat should receive more of less medication. Some animals have seizures controlled with blood levels of drug at the low end of the therapeutic range while others will need higher drug levels to experience beneficial effects.
Blood levels of phenobarbitone should be measured:
- 2 weeks after starting treatment or changing the dosage.
- If the seizures seems to be occurring more often.
- Every 3 to 6 months to check that blood concentration does not drift out of the intended range.
- When drug-related side effects are suspected.
Occasionally the side effects of drugs used in the management of epileptic seizures can be worse than the seizures themselves. Mild side effects are common when treatment is first started (or the dose is increased). Phenobarbitone can cause increased thirst and appetite, more frequent urination, mild sedation and mild wobbliness in the back legs.
More serious side effects are rarely seen with phenobarbitone but include liver toxicity and blood abnormalities (low red blood cells, low platelets and low white blood cell count). Liver toxicity is mainly seen in cats on diazepam. Complete blood profiles (liver function tests and haematology) are recommended on a six monthly basis to monitor to such potential side-effects.
There are many reasons why an animal may not respond to treatment:
- Incorrect diagnosis of epilepsy (if there is an underlying cause for the seizures).
- Insufficient dose of medication.
- Development of ‘resistance’ to the effect of the drug (also known refractory epilepsy).
If the quality of life of an epileptic animal is compromised by frequent and/or severe seizures despite appropriate choice and blood concentration of drug, they can be classified as having refractory epilepsy.
The first choice for treatment of refractory epilepsy in cats receiving phenobarbitone treatment is to add diazepam or one of the newer (and more expensive) human anti-epileptic drugs, eg gabapentin (NeurotinR) or levetiracetam (KeppraR).
It is very likely that your pet will have to stay on treatment for the rest of its life. It is important not to alter or stop your pet’s treatment without veterinary advice. Dosage reduction should only be considered if your pet has had no seizures for at least a year. Sudden changes in the blood levels of anti-epileptic drugs can trigger seizures. If drug doses are reduced this should be done very gradually over many months. However, if your pet is not experiencing significant side-effects, you should not be concerned that they need to remain on treatment.