The most common medications given to dogs for seizures are phenobarbital and potassium bromide, both considered first-line treatments by veterinarians. Which medication your vet recommends depends on your dog’s seizure frequency, overall health, and how well they tolerate side effects. Beyond daily medications, there are also rescue drugs for emergencies, newer pharmaceutical options, and dietary approaches that can help reduce seizure frequency.
First-Line Seizure Medications
Phenobarbital has been the most widely used anticonvulsant in dogs for decades. It works by calming excessive electrical activity in the brain and is typically given twice daily. Most dogs respond well to it, but it comes with notable side effects: increased thirst, increased appetite, and drowsiness, especially in the first few weeks. The most common change vets see on bloodwork is a rise in liver enzyme levels, which can show up as early as two weeks after starting treatment. Over time, phenobarbital can stress the liver, so dogs on this medication need a blood panel every six months to catch any problems early. It can also lower thyroid hormone levels, which sometimes leads to a mistaken diagnosis of thyroid disease.
Potassium bromide is the other frontline option and is increasingly used as a first choice, particularly for dogs with existing liver concerns. It’s processed by the kidneys rather than the liver, making it a gentler option for dogs who can’t tolerate phenobarbital. The trade-off is that it takes longer to reach effective levels in the body, sometimes several weeks, so your vet may use a loading dose to speed things up. Some dogs do best on a combination of both medications.
Newer Medication Options
Zonisamide is a newer-generation anticonvulsant that has gained traction as both an add-on therapy and a standalone treatment. A prospective clinical trial published in the Journal of Veterinary Internal Medicine found it effective as a first-line medication for dogs with newly diagnosed idiopathic epilepsy, with most dogs responding well at a starting dose given twice daily. Dogs in that study were followed for at least 12 weeks, and the researchers concluded zonisamide is a suitable first-choice option for canine epilepsy.
Levetiracetam is another second-generation option, often added when a dog’s seizures aren’t fully controlled by phenobarbital or bromide alone. It has a relatively mild side-effect profile, which makes it appealing, though it typically needs to be given three times a day. All of these medications require periodic blood level monitoring to make sure the dose stays in the effective range.
Rescue Medications for Emergencies
A seizure lasting longer than five minutes, or two or more seizures within 24 hours, is a veterinary emergency. If your dog has a history of prolonged seizures or clusters, your vet may prescribe a rescue medication to keep at home.
The two most common options are rectal diazepam (a form of valium delivered with a needleless syringe) and intranasal midazolam (sprayed into the nose using an atomizer device). Both are benzodiazepines that work quickly to interrupt seizure activity. A multicenter clinical trial comparing the two found intranasal midazolam to be a valuable option when you can’t get to a vet immediately, and many owners find nasal delivery easier to administer during an active seizure than rectal delivery. Your vet can walk you through the specific technique and provide the device you’ll need.
What to Do During a Seizure
When your dog is actively seizing, the most important thing is to keep them safe without intervening physically. Move furniture or hard objects away from them, but do not try to restrain them or hold them down. Keep your hands away from their mouth. Dogs do not swallow their tongues during seizures, and putting your fingers near their jaw puts you at serious risk of being bitten. Stay calm, note the time the seizure started, and let it run its course. If it lasts longer than five minutes, administer any prescribed rescue medication and head to your nearest emergency vet.
CBD Oil as an Add-On Treatment
CBD has shown modest but real benefits for dogs whose seizures aren’t fully controlled by standard medications. A double-blinded, placebo-controlled crossover study of 51 dogs with drug-resistant epilepsy tested CBD at two different doses. The lower dose (5 mg/kg/day) didn’t produce meaningful results. The higher dose (9 mg/kg/day) reduced the number of seizure days by 24.1% compared to baseline, a statistically significant improvement. Dogs on the placebo, by contrast, saw a slight increase in seizure days.
The study also found that blood levels of CBD were about seven times higher at the 9 mg/kg dose compared to the 5 mg/kg dose, despite the dose itself being less than double. This suggests CBD absorption in dogs isn’t straightforward, and getting the dose right matters a great deal. The medication was generally well tolerated, but liver enzymes should be monitored, since CBD can affect liver function, especially when combined with other seizure drugs. CBD is not a replacement for conventional medications. It works best as an addition to an existing treatment plan.
Dietary Approaches
Medium-chain triglyceride (MCT) oil, a fat derived from coconut and palm kernel oil, has shown promise as a dietary supplement for epileptic dogs. MCTs provide an alternative energy source for the brain, and clinical trials have tested diets enriched with 5.5% to 6.5% MCT oil in dogs with idiopathic epilepsy. Some dogs on these diets experienced fewer seizures. Pushing the MCT content up to 9% can reduce palatability, meaning some dogs simply won’t eat the food, so there’s a practical ceiling to how much you can add.
Several commercial dog foods are now formulated with MCT oil specifically for dogs with epilepsy. This isn’t a standalone treatment, but it can complement medication. If you’re interested, ask your vet about therapeutic diets designed for neurological support rather than simply adding coconut oil to your dog’s regular food, since the concentration and type of MCTs matter.
Monitoring Over the Long Term
Seizure management in dogs is rarely a “set it and forget it” situation. Most anticonvulsants require regular blood level checks to confirm the drug is in the therapeutic range and isn’t damaging the liver or kidneys. For dogs on phenobarbital, a full blood chemistry panel every six months is standard. If liver function looks questionable, your vet may run a bile acid tolerance test for a closer look. Dogs on bromide, zonisamide, or levetiracetam also need periodic drug level monitoring, though the specific schedule varies.
Keep a seizure diary noting the date, time, duration, and any unusual behavior before or after each episode. This log is one of the most valuable tools your vet has for adjusting treatment. A dog that goes from four seizures a month to one is responding well, even if seizures haven’t stopped entirely. Complete seizure freedom is the goal, but for many dogs, significant reduction in frequency and severity is a realistic and meaningful outcome.