When does treatment start?
“Should we be giving her medication?” is one of the first questions every owner asks. The honest answer is: not always, and not immediately.
The decision to start anti-epileptic drugs (AEDs) is made case by case. Your vet will typically recommend treatment if any of the following apply:
- Two or more seizures within a six-month period
- Cluster seizures (two or more within 24 hours) at any frequency
- Status epilepticus - a single seizure lasting more than 5 minutes, or seizures without recovery between them
- Severe post-ictal signs such as prolonged blindness, aggression, or extreme disorientation
- A known structural cause where waiting risks further damage
If seizures are infrequent and mild, your vet may advise watchful waiting with careful monitoring rather than immediate medication.
First-line medications
Phenobarbital (phenobarbitone)
The most widely used AED in dogs. Phenobarbital reduces seizure frequency in around 60–85% of dogs. It is inexpensive, well understood, and available in generic form. It does require regular blood monitoring to check drug levels and assess liver function - typically at 2 weeks, 6 months, then annually.
Common side effects (especially early on): increased thirst, hunger, urination, and mild sedation. Most settle within a few weeks.
Imepitoin (Pexion)
A newer, veterinary-licensed AED (licensed in the UK and EU). Imepitoin has a good safety profile and fewer side effects than phenobarbital. It does not require liver monitoring. Some vets now use it as a first-line choice, particularly for dogs with milder epilepsy. It is generally more expensive than phenobarbital.
Add-on and second-line options
If seizures are not adequately controlled on a single drug, vets often add a second AED rather than replacing the first.
Potassium Bromide (KBr)
Commonly added alongside phenobarbital when seizures are not fully controlled. Potassium bromide takes 3–6 months to reach a stable level in the blood, so results take time. Salt intake affects drug levels, so a consistent diet is important. It can cause sedation and rear-limb weakness in some dogs.
Levetiracetam (Keppra)
A human AED used off-label in dogs. Fast-acting and very safe. Often used as an add-on or short-term “pulse therapy” around known high-risk periods (e.g. around cluster episodes). Requires three-times-daily dosing with standard formulations, though extended-release versions are available.
Zonisamide
Another human AED used off-label. Well tolerated and sometimes used when phenobarbital is not suitable (e.g. due to liver concerns). Twice-daily dosing. Less commonly prescribed in the UK than in the US.
What does long-term management look like?
Epilepsy is a lifelong condition. Once medication starts, it should never be stopped abruptly - this can trigger a rebound increase in seizures. Any dose changes should be made slowly and under veterinary supervision.
Typical ongoing monitoring includes:
- Regular blood tests to check drug levels and organ function
- Seizure diary reviews - your vet will want to see frequency trends, not just a verbal summary
- Dose adjustments as your dog ages or changes weight
What if medication does not work?
Around 20–30% of dogs with idiopathic epilepsy are considered “drug resistant” - seizures cannot be fully controlled despite appropriate medication. In these cases, referral to a veterinary neurologist is usually recommended to explore additional options, re-evaluate the diagnosis, and optimise the treatment regimen.
Most dogs find a regimen that works. It takes time and patience, but you’ll get there.