# Zonisamide Seizure Dogs: Modern Anti-Seizure Dose and Liver Safety


## Key Takeaways

- Modern zonisamide dosing for canine epilepsy targets serum concentrations within a therapeutic range of 10-55 µg/mL, achieved through titration based on blood levels and clinical response, rather than fixed milligram-per-kilogram doses.
- Zonisamide is an effective first-line monotherapy for newly diagnosed idiopathic epilepsy, with studies reporting ≥50% seizure frequency reduction in 76% of dogs and complete seizure freedom in 55%.
- The most significant safety concern is rare but potentially fatal hepatotoxicity, with acute clinical hepatopathy occurring in approximately 0.52% of dogs, necessitating baseline and regular liver enzyme monitoring.
- Zonisamide can cause other adverse effects including behavioral changes (aggression, restlessness), distal renal tubular acidosis, gastrointestinal upset, and transient neurological signs like sedation and ataxia.
- Concurrent administration with phenobarbital requires careful monitoring, as phenobarbital can increase zonisamide clearance, while zonisamide may elevate phenobarbital levels, potentially exceeding hepatotoxic thresholds.
- Baseline diagnostics including CBC, biochemistry panel (ALT, ALP, albumin), and urinalysis are crucial before initiating zonisamide, followed by routine monitoring of serum drug concentrations and liver enzymes every six months.

---

If your [dog](/knowledge/veterinary-medicine/clinical-methods/dog) has been diagnosed with epilepsy, your veterinarian may recommend zonisamide. This anti-seizure medication (ASM) is now a first-line option for canine epilepsy, not just a rescue drug. Modern dosing targets a specific blood level, not just a fixed milligram-per-kilogram dose. The most important safety concern is liver injury, which is rare but potentially fatal. This article explains current dosing protocols, what blood tests are needed, and how to monitor for liver problems.

**Owner Triage Summary:** If your dog has a seizure lasting more than 5 minutes, multiple seizures in 24 hours, or does not recover consciousness between seizures, this is an emergency. Go to the nearest veterinary emergency room immediately. Do not try to give any medication by mouth during a seizure. For a first-time seizure, call your veterinarian the same day. For dogs already on zonisamide, do not stop the medication suddenly, as this can trigger withdrawal seizures.

## What is Zonisamide and How Does It Work?

Zonisamide is a newer generation ASM used to treat epilepsy in dogs and cats [<a href="#ref-1">1</a>]. It is a sulfonamide derivative, but it does not have the antibacterial properties of other sulfa drugs. The exact mechanism of action is not fully understood, but it is known to block sodium channels and T-type calcium channels, which stabilizes neuronal membranes and reduces abnormal electrical firing in the brain.

In veterinary medicine, zonisamide has gained popularity because it is generally well-tolerated and has fewer sedative effects compared to phenobarbital. It is used both as an add-on therapy for dogs with refractory epilepsy and as a monotherapy for newly diagnosed cases [<a href="#ref-2">2</a>][<a href="#ref-1">1</a>].

## Modern Dosing Protocols for Zonisamide in Dogs

The old approach to zonisamide dosing was a fixed "one size fits all" milligram per kilogram dose. Modern veterinary practice uses a target range based on therapeutic drug monitoring (TDM). This means measuring the actual concentration of the drug in the blood and adjusting the dose to keep it within a specific reference interval.

### Starting Dose and Titration

The current evidence supports a starting dose of approximately **5 to 10 mg/kg given orally every 12 hours**. In a large 2024 prospective study of 56 dogs with newly diagnosed idiopathic epilepsy, dogs were started on 2.7 to 14.4 mg/kg zonisamide every 12 hours [<a href="#ref-1">1</a>]. The study found that for 90% of dogs that achieved a good response, the mean dose was **4.8 mg/kg every 12 hours** (range 2.7 to 8.6 mg/kg) [<a href="#ref-1">1</a>].

This is a change from older recommendations. A 2004 study used a mean dose of 8.9 mg/kg every 12 hours to achieve therapeutic levels [<a href="#ref-3">3</a>]. A 2012 study used 5 to 15 mg/kg every 12 hours [<a href="#ref-4">4</a>]. The trend is toward lower starting doses with careful titration based on blood levels and clinical response.

### Therapeutic Drug Monitoring and Reference Intervals

The goal of dosing is to achieve a serum zonisamide concentration within a therapeutic range. Historically, the target range was **10 to 40 µg/mL** [<a href="#ref-3">3</a>]. However, a landmark 2026 retrospective study of 207 dogs established a new, evidence-based reference interval.

This study, which included only dogs receiving zonisamide as monotherapy, proposed a reference interval of **10 to 55 µg/mL** based on the plasma concentrations found in dogs that responded well to treatment [<a href="#ref-2">2</a>]. In this study, 59% of dogs were classified as responders, with 29% achieving complete seizure freedom and 30% having a partial response [<a href="#ref-2">2</a>].

This new upper limit of 55 µg/mL is important. It suggests that some dogs may need higher blood levels than previously thought to achieve seizure control. However, it does not mean that all dogs need to be at the high end of this range. The dose should be individualized based on seizure control and adverse effects.

### Practical Dosing Algorithm

1.  **Start:** Begin at 5 mg/kg PO q12h.
2.  **Titrate:** After 2 weeks, measure a trough serum zonisamide concentration (sample drawn just before the next dose).
3.  **Adjust:** If the level is below 10 µg/mL and seizures are not controlled, increase the dose by 20-30% and recheck in 2 weeks.
4.  **Maintain:** Once the level is within 10-55 µg/mL and seizures are controlled, continue at that dose.
5.  **Recheck:** Measure serum levels again if seizures recur, if side effects develop, or if other medications are added or removed.

### At a Glance: Zonisamide Dosing and Monitoring

| Parameter | Traditional Approach | Modern Approach | Evidence |
| :--- | :--- | :--- | :--- |
| **Starting Dose** | 5-10 mg/kg PO q12h | 2.7-8.6 mg/kg PO q12h, titrated to effect | [<a href="#ref-1">1</a>][<a href="#ref-3">3</a>] |
| **Target Trough Level** | 10-40 µg/mL | 10-55 µg/mL | [<a href="#ref-2">2</a>][<a href="#ref-3">3</a>] |
| **Monitoring Frequency** | As needed for seizures | Routine TDM at 2 weeks, then as needed | [<a href="#ref-2">2</a>] |
| **Monotherapy Efficacy** | ~58-60% responder rate | ~59-76% responder rate | [<a href="#ref-2">2</a>][<a href="#ref-1">1</a>][<a href="#ref-4">4</a>] |

## Zonisamide Monotherapy for Idiopathic Epilepsy

Zonisamide is no longer just an add-on drug. It is an effective first-line monotherapy for dogs with newly diagnosed idiopathic epilepsy.

A 2024 prospective multicenter study evaluated 56 dogs with newly diagnosed idiopathic epilepsy that had not received any prior ASM treatment [<a href="#ref-1">1</a>]. The dogs were treated with zonisamide monotherapy for at least 12 weeks. The results were encouraging:
- **76%** of dogs had a ≥50% reduction in seizure frequency.
- **55%** of dogs achieved complete seizure freedom [<a href="#ref-1">1</a>].

These numbers are comparable to what is expected with phenobarbital monotherapy, but with a different side effect profile. A 2023 study comparing caregiver assessments of outcome found that dogs on zonisamide monotherapy had a significantly lower prevalence of reported adverse effects (39%) compared to dogs on phenobarbital monotherapy (77%) [<a href="#ref-5">5</a>]. This makes zonisamide an attractive option for owners who are concerned about the sedative and behavioral side effects of phenobarbital.

The 2026 reference interval study further supports zonisamide monotherapy. In this cohort of 207 dogs, 59% responded to zonisamide alone, with no other ASMs on board [<a href="#ref-2">2</a>]. This large dataset provides strong evidence that zonisamide is a reliable first-line treatment.

## Zonisamide as Add-On Therapy for Refractory Epilepsy

For dogs that do not respond adequately to phenobarbital or potassium bromide, zonisamide is a valuable add-on agent.

An early prospective study from 2004 evaluated zonisamide as an add-on therapy in 12 dogs with poorly controlled idiopathic epilepsy. The mean dosage required to achieve therapeutic serum concentrations was 8.9 mg/kg q12h. Seven dogs (58%) responded favorably, with a mean reduction in seizure frequency of 81.3% [<a href="#ref-3">3</a>].

A 2007 study of 13 dogs with refractory epilepsy found that 9 of 11 evaluable dogs were responders, with a median reduction in seizure frequency of 70% [<a href="#ref-6">6</a>]. The study noted that only transient central nervous system side effects were reported, and importantly, there was no further increase in liver enzymes [<a href="#ref-6">6</a>].

### Drug Interactions: The Phenobarbital Effect

When using zonisamide with phenobarbital, an important drug interaction must be considered. Phenobarbital induces hepatic enzymes (specifically CYP450 enzymes) that are responsible for metabolizing zonisamide. This means that phenobarbital increases the clearance of zonisamide and decreases its elimination half-life [<a href="#ref-7">7</a>].

The clinical consequence is that dogs on phenobarbital may need higher or more frequent doses of zonisamide to maintain therapeutic blood levels. However, a 2024 case series revealed a more complex interaction. When zonisamide was added to phenobarbital, the serum phenobarbital concentrations increased in 9 out of 10 dogs, despite no change in the phenobarbital dose [<a href="#ref-7">7</a>]. In five dogs, the phenobarbital levels rose above the reported hepatotoxic threshold of 35 mg/L, requiring a reduction in the phenobarbital dose [<a href="#ref-7">7</a>].

This is a critical safety finding. When adding zonisamide to a phenobarbital regimen, veterinarians must monitor both drug levels closely. The dose of phenobarbital may need to be reduced to avoid toxicity.

## Liver Safety: Understanding the Risk

The most serious concern with zonisamide is hepatotoxicity. While rare, it can be fatal. Understanding the scope of this risk is essential for any owner considering this medication.

### Incidence of Hepatopathy

A 2022 multicenter retrospective study is the most definitive source on this topic. It reviewed the records of 384 dogs that received zonisamide orally [<a href="#ref-8">8</a>]. The results were as follows:
- **Acute clinical hepatopathy** occurred in 2 of 384 dogs (0.52%, 95% CI 0.06-1.9%). These cases occurred after 13-16 days of treatment.
- **One additional dog** had elevated ALT activity without clinical signs.
- Of these 3 dogs, 2 recovered after stopping zonisamide, and 1 was euthanized due to liver failure [<a href="#ref-8">8</a>].

This means that approximately 1 in 200 dogs may develop a significant liver problem. The risk is low, but it is real.

### Chronic Liver Changes

In the same 2022 study, 117 dogs were chronically administered zonisamide (median 20 months, range 5-94 months). Of these, 10 had an increase in alkaline phosphatase (ALP), 6 had an increase in alanine aminotransferase (ALT), and 1 had hypoalbuminemia. However, none of these dogs showed clinical signs of liver disease [<a href="#ref-8">8</a>].

This suggests that chronic zonisamide use can cause mild, subclinical liver enzyme elevations. These changes may not require discontinuation of the drug, but they do warrant monitoring.

### Case Reports of Severe Liver Injury

Several case reports highlight the potential for severe, idiosyncratic liver injury.

- **Acute Idiosyncratic Hepatic Necrosis:** A 2011 case report described a dog that developed acute hepatic necrosis associated with zonisamide administration [<a href="#ref-9">9</a>]. This is the type of idiosyncratic reaction that cannot be predicted by dose or duration of therapy.
- **Chronic Hepatocellular Necrosis:** A 2020 case report from Japan described a 16-year-old Miniature Dachshund that had been on zonisamide for 1 year. The dog presented with vomiting, anorexia, and diarrhea. Histopathology revealed hepatocellular necrosis with prominent regenerative reactions, which was attributed to chronic persistent liver injury from zonisamide [<a href="#ref-10">10</a>].
- **Immune-Mediated Reactions:** A 2024 case report described a dog that developed immune-mediated polyarthritis (IMPA) and anterior uveitis after zonisamide was added to its anti-epileptic regimen. These conditions resolved within weeks of discontinuing the drug, indicating an idiosyncratic immune-mediated reaction [<a href="#ref-11">11</a>].

### What Do These Liver Changes Mean?

The liver enzyme elevations seen with zonisamide can be divided into two categories:

1.  **Enzyme Induction:** Zonisamide can induce liver enzymes, leading to a mild increase in ALP without actual liver damage. This is similar to what is seen with phenobarbital and is generally not a cause for alarm.
2.  **Hepatocellular Injury:** Increases in ALT, especially if accompanied by clinical signs like vomiting, lethargy, or jaundice, indicate true liver cell damage. This is the dangerous form of hepatotoxicity.

The distinction between these two is critical. A mild ALP increase alone may not require any action. An ALT increase, or any increase accompanied by clinical signs, requires immediate veterinary attention.

## Other Adverse Effects and Safety Concerns

While liver safety is the primary concern, zonisamide is associated with other adverse effects that owners should be aware of.

### Psychiatric and Behavioral Effects

A 2021 case report described three dogs that developed abnormal behavior episodes while on zonisamide. These episodes included sudden rage and aggression toward family members, insomnia, restlessness, and constant attention-seeking behavior [<a href="#ref-12">12</a>].

Key features of these behavioral reactions:
- The behaviors deteriorated with gradual dose increments of zonisamide.
- They almost completely disappeared within 5 days of discontinuing the drug.
- The exact same episodes relapsed within days of re-administration.
- They disappeared again shortly after discontinuation [<a href="#ref-12">12</a>].

This is a rare but important side effect. If a dog becomes aggressive or behaves abnormally after starting zonisamide, the medication should be considered a possible cause.

### Renal Tubular Acidosis

Zonisamide can cause a distal renal tubular acidosis (RTA) in some dogs. This is a condition where the kidneys cannot properly excrete acid, leading to a metabolic acidosis.

- A 2011 case report described a dog with RTA associated with zonisamide therapy [<a href="#ref-13">13</a>].
- A 2022 case report described a 3-year-old Golden Retriever that developed lethargy and had a normal anion gap metabolic acidosis with hypokalemia, hyperchloremia, and alkaline urine. The serum zonisamide concentration was close to the upper limit of the therapeutic range. The adverse effects abated when the zonisamide dosage was reduced [<a href="#ref-14">14</a>].

RTA is a serious condition that requires veterinary intervention. Signs include lethargy, weakness, and increased thirst and urination.

### Gastrointestinal and Neurologic Effects

In the 2024 prospective monotherapy study, 7 of 56 dogs (13%) experienced reduced activity, decreased appetite, vomiting, hindlimb weakness, soft stools, or constipation [<a href="#ref-1">1</a>]. These effects were generally mild and transient.

A 2004 study reported mild side effects such as transient sedation, ataxia, and vomiting in six of twelve dogs [<a href="#ref-3">3</a>]. These effects often resolve on their own as the dog adjusts to the medication.

### Rectal Administration

For dogs that cannot take oral medication during a seizure, rectal administration of zonisamide is an option. A 2015 pharmacokinetic study evaluated this route.

- Zonisamide was administered rectally in either polyethylene glycol (PEG) or water.
- The mean relative bioavailability of PEG was 85%, which was significantly higher than that of water (53%).
- The maximum plasma concentration was significantly higher after oral administration (11.56 µg/mL) compared to rectal administration in water (5.00 µg/mL) [<a href="#ref-15">15</a>].

This means that rectal administration is possible, but the vehicle matters. PEG is preferred over water for rectal dosing. However, oral administration still achieves the highest blood levels.

## Monitoring Protocols for Dogs on Zonisamide

Given the risks of hepatotoxicity and other adverse effects, a structured monitoring protocol is essential.

### Baseline Testing

Before starting zonisamide, your veterinarian should perform:
- A complete blood count (CBC)
- A serum biochemistry panel, including ALT, ALP, and albumin
- A urinalysis

These baseline tests help rule out pre-existing liver or kidney disease and provide a reference point for future comparisons.

### Follow-Up Testing Schedule

| Time Point | Tests Recommended | Rationale |
| :--- | :--- | :--- |
| **2 weeks after starting** | Serum zonisamide concentration, ALT, ALP | Establish initial drug level and check for early liver enzyme changes |
| **4-6 weeks after starting** | Serum zonisamide concentration, ALT, ALP | Confirm steady-state drug level and monitor for delayed enzyme changes |
| **Every 6 months** | ALT, ALP, serum zonisamide concentration | Routine monitoring for chronic therapy |
| **Any time clinical signs develop** | CBC, biochemistry panel, urinalysis, serum zonisamide concentration | Investigate potential adverse effects |

### What to Watch For at Home

Owners should monitor their dogs for the following signs that could indicate a problem:
- **Liver issues:** Vomiting, diarrhea, loss of appetite, lethargy, jaundice (yellowing of the gums, skin, or eyes), dark urine.
- **Kidney issues:** Increased thirst, increased urination, lethargy, weakness.
- **Behavioral issues:** Aggression, restlessness, insomnia, unusual attention-seeking behavior.
- **Gastrointestinal issues:** Vomiting, diarrhea, constipation, decreased appetite.

If any of these signs appear, contact your veterinarian immediately. Do not wait for the next scheduled check-up.

## Contraindications and Precautions

Zonisamide should be used with caution or avoided in certain situations.

- **Known Hypersensitivity:** Dogs with a known allergy to sulfonamides may be at increased risk of a reaction, although zonisamide is a sulfonamide derivative that does not have antibacterial activity.
- **Pre-existing Liver Disease:** Zonisamide is metabolized by the liver. Dogs with significant pre-existing liver disease should only be treated with zonisamide if the benefits clearly outweigh the risks, and with very close monitoring.
- **Pre-existing Kidney Disease:** Zonisamide and its metabolites are excreted by the kidneys. Dose adjustments may be needed in dogs with renal impairment.
- **Pregnancy and Lactation:** The safety of zonisamide in pregnant or lactating dogs has not been established. It should only be used if the benefits clearly outweigh the risks.

## Zonisamide and the Gut Microbiome

Emerging research is exploring the link between the gut microbiome and epilepsy. A 2020 pilot study evaluated fecal Lactobacillus populations in dogs with idiopathic epilepsy compared to healthy dogs. The study did not find any statistically significant differences in Lactobacillus populations between the two groups [<a href="#ref-16">16</a>].

While this is an area of active research, there is no current evidence that zonisamide has a direct effect on the gut microbiome, nor that manipulating the microbiome can improve zonisamide's efficacy. This remains a topic for future investigation.

## Dietary Considerations

A 2023 study evaluated the effect of a medium-chain triglyceride (MCT) enriched therapeutic diet on dogs with idiopathic epilepsy treated with zonisamide. The study was a prospective, randomized, double-blinded, placebo-controlled, crossover design involving 7 dogs [<a href="#ref-17">17</a>].

The results showed no significant difference in seizure frequency between the placebo diet (2.95 seizures/month) and the MCT-enriched diet (1.90 seizures/month) over the 6-month trial. However, 3 of 7 dogs showed a ≥50% reduction in seizures while on the MCT diet [<a href="#ref-17">17</a>].

This suggests that an MCT-enriched diet may be a useful adjunctive therapy for some dogs on zonisamide, but it is not a guaranteed treatment. Owners should discuss dietary changes with their veterinarian before implementing them.

## Comparison with Other Anti-Seizure Medications

Understanding how zonisamide compares to other ASMs helps owners make informed decisions.

| Medication | Efficacy (≥50% reduction) | Common Side Effects | Monitoring Required |
| :--- | :--- | :--- | :--- |
| **Zonisamide** | 59-76% [<a href="#ref-2">2</a>][<a href="#ref-1">1</a>] | Sedation, ataxia, vomiting, rare hepatotoxicity | TDM, liver enzymes |
| **Phenobarbital** | ~60-80% | Sedation, ataxia, polyphagia, polydipsia, liver enzyme induction | TDM, liver enzymes |
| **Levetiracetam** | ~50-60% | Sedation, ataxia (often transient) | TDM (less critical) |
| **Potassium Bromide** | ~50-70% | Sedation, hindlimb weakness, pancreatitis (rare), skin reactions | Serum bromide levels |

A 2023 study compared caregiver assessments of outcome in dogs on levetiracetam, zonisamide, or phenobarbital monotherapy. The study found a significant improvement in mean quality of life score during monotherapy compared to before treatment, with no difference identified between monotherapy groups. However, the prevalence of adverse effects was significantly higher in the phenobarbital group (77%) compared to the zonisamide group (39%) [<a href="#ref-5">5</a>].

This supports the use of zonisamide as a first-line agent, particularly for owners who are concerned about the side effect profile of phenobarbital.

## Prognosis and Long-Term Management

The prognosis for dogs with idiopathic epilepsy treated with zonisamide is generally good, but it depends on the individual dog.

- **Seizure Freedom:** In the 2024 study, 55% of dogs achieved complete seizure freedom on zonisamide monotherapy [<a href="#ref-1">1</a>].
- **Partial Response:** An additional 21% had a ≥50% reduction in seizure frequency [<a href="#ref-1">1</a>].
- **Non-Responders:** Approximately 25-40% of dogs will not respond adequately to zonisamide and may require a different ASM or a combination of drugs [<a href="#ref-2">2</a>][<a href="#ref-1">1</a>].

Long-term management requires a partnership between the owner and the veterinarian. Regular monitoring, consistent medication administration, and prompt reporting of any adverse effects are essential for success.

## Limitations and When to Contact a Veterinarian

This article provides general information about zonisamide for seizures in dogs. It is educational and is not a substitute for veterinary diagnosis or treatment.

**Important Limitations:**
- **Breed Variability:** This article cannot predict how a specific breed will respond to zonisamide. While some breeds may have a genetic predisposition to certain drug reactions, the data from the approved sources do not provide breed-specific risk profiles for zonisamide.
- **Individual Response:** Every dog is different. Some dogs will respond well to a low dose, while others will need a high dose or will not respond at all.
- **Drug Interactions:** This article covers the interaction with phenobarbital, but zonisamide may interact with other medications not discussed here.

**Contact your veterinarian immediately if:**
1.  Your dog has a seizure lasting more than 5 minutes.
2.  Your dog has more than one seizure in 24 hours.
3.  Your dog does not regain consciousness within 30 minutes after a seizure.
4.  Your dog develops vomiting, diarrhea, or loss of appetite.
5.  Your dog shows signs of jaundice (yellow gums, skin, or eyes).
6.  Your dog becomes unusually aggressive, restless, or lethargic.
7.  Your dog is drinking or urinating significantly more than usual.
8.  You miss a dose of zonisamide and need advice on how to proceed.

## Frequently Asked Questions

### How long does it take for zonisamide to start working in dogs?
Zonisamide reaches steady-state blood concentrations in approximately 1 to 2 weeks. Some dogs may show improvement in seizure frequency within the first few days, but a full assessment of efficacy is usually made after 4 to 6 weeks of consistent dosing.

### Can zonisamide be given with food?
Yes, zonisamide can be given with or without food. Giving it with food may help reduce the likelihood of gastrointestinal upset, such as vomiting or decreased appetite, which are potential side effects.

### What is the most common side effect of zonisamide in dogs?
The most common side effects are transient sedation, ataxia (wobbliness), and vomiting. These effects are often mild and may resolve on their own within the first few weeks of treatment as the dog adjusts to the medication.

### How often does liver failure occur in dogs taking zonisamide?
Liver failure is rare. A large retrospective study found that acute clinical hepatopathy occurred in 0.52% of treated dogs, or about 1 in 200. Of these, most recovered after stopping the drug, but some cases can be fatal.

### Can zonisamide cause aggression in dogs?
Yes, a case report has documented abnormal behavior episodes, including sudden rage and aggression, in three dogs. These behaviors disappeared when the drug was discontinued and relapsed when it was re-administered.

### Is zonisamide safe to use with phenobarbital?
Zonisamide can be used with phenobarbital, but it requires careful monitoring. Phenobarbital increases the clearance of zonisamide, and zonisamide can increase phenobarbital levels. Both drug levels must be checked to avoid toxicity.

### What should I do if I miss giving my dog a dose of zonisamide?
If you miss a dose, give it as soon as you remember, unless it is almost time for the next dose. In that case, skip the missed dose and continue with the regular schedule. Do not give a double dose. Contact your veterinarian if you have any concerns.

### Are there any dietary restrictions for dogs taking zonisamide?
There are no specific dietary restrictions for dogs on zonisamide. Some studies have explored MCT-enriched diets as an adjunctive therapy, with mixed results. Always discuss any dietary changes with your veterinarian.

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## Sources

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<a id="ref-2"></a>[<a href="#ref-2">2</a>] [Efficacy of monotherapy with zonisamide and proposed reference interval in dogs with epilepsy: a cohort of 207 dogs (2011-2021).](https://pubmed.ncbi.nlm.nih.gov/41742507/)

<a id="ref-3"></a>[<a href="#ref-3">3</a>] [Zonisamide therapy for refractory idiopathic epilepsy in dogs.](https://pubmed.ncbi.nlm.nih.gov/15238558/)

<a id="ref-4"></a>[<a href="#ref-4">4</a>] [Zonisamide monotherapy for idiopathic epilepsy in dogs.](https://pubmed.ncbi.nlm.nih.gov/22639873/)

<a id="ref-5"></a>[<a href="#ref-5">5</a>] [Comparison of caregivers' assessments of clinical outcome in dogs with idiopathic epilepsy administered levetiracetam, zonisamide, or phenobarbital monotherapy.](https://pubmed.ncbi.nlm.nih.gov/36965471/)

<a id="ref-6"></a>[<a href="#ref-6">6</a>] [Prospective study of zonisamide therapy for refractory idiopathic epilepsy in dogs.](https://pubmed.ncbi.nlm.nih.gov/17355603/)

<a id="ref-7"></a>[<a href="#ref-7">7</a>] [The effect of oral zonisamide treatment on serum phenobarbital concentrations in epileptic dogs.](https://pubmed.ncbi.nlm.nih.gov/38868500/)

<a id="ref-8"></a>[<a href="#ref-8">8</a>] [Incidence of hepatopathies in dogs administered zonisamide orally: A retrospective study of 384 cases.](https://pubmed.ncbi.nlm.nih.gov/35238072/)

<a id="ref-9"></a>[<a href="#ref-9">9</a>] [Apparent acute idiosyncratic hepatic necrosis associated with zonisamide administration in a dog.](https://pubmed.ncbi.nlm.nih.gov/21985145/)

<a id="ref-10"></a>[<a href="#ref-10">10</a>] [Hepatocellular necrosis with prominent regenerative reactions in a zonisamide administrated dog.](https://pubmed.ncbi.nlm.nih.gov/32249255/)

<a id="ref-11"></a>[<a href="#ref-11">11</a>] [Immune-mediated polyarthritis and anterior uveitis secondary to zonisamide administration in a dog with refractory epilepsy.](https://pubmed.ncbi.nlm.nih.gov/38403976/)

<a id="ref-12"></a>[<a href="#ref-12">12</a>] [Abnormal Behavior Episodes Associated With Zonisamide in Three Dogs: A Case Report.](https://pubmed.ncbi.nlm.nih.gov/34778438/)

<a id="ref-13"></a>[<a href="#ref-13">13</a>] [Renal tubular acidosis associated with zonisamide therapy in a dog.](https://pubmed.ncbi.nlm.nih.gov/22092642/)

<a id="ref-14"></a>[<a href="#ref-14">14</a>] [Distal renal tubular acidosis and lethargy associated with zonisamide treatment in a dog with idiopathic epilepsy.](https://pubmed.ncbi.nlm.nih.gov/35916390/)

<a id="ref-15"></a>[<a href="#ref-15">15</a>] [Pharmacokinetics of single-dose rectal zonisamide administration in normal dogs.](https://pubmed.ncbi.nlm.nih.gov/25818215/)

<a id="ref-16"></a>[<a href="#ref-16">16</a>] [Evaluation of fecal Lactobacillus populations in dogs with idiopathic epilepsy: a pilot study.](https://pubmed.ncbi.nlm.nih.gov/32747877/)

<a id="ref-17"></a>[<a href="#ref-17">17</a>] [Efficacy evaluation of a commercially available MCT enriched therapeutic diet on dogs with idiopathic epilepsy treated with zonisamide: a prospective, randomized, double-blinded, placebo-controlled, crossover dietary preliminary study.](https://pubmed.ncbi.nlm.nih.gov/37674206/)

<a id="ref-18"></a>[<a href="#ref-18">18</a>] [Safety and efficacy of cannabidiol-cannabidiolic acid rich hemp extract in the treatment of refractory epileptic seizures in dogs.](https://pubmed.ncbi.nlm.nih.gov/35967998/)

<a id="ref-19"></a>[<a href="#ref-19">19</a>] [Retrospective study on canine idiopathic epilepsy treatment in primary care practices in the United States.](https://pubmed.ncbi.nlm.nih.gov/41737686/)

<a id="ref-20"></a>[<a href="#ref-20">20</a>] [Population pharmacokinetics of extended-release levetiracetam in epileptic dogs when administered alone, with phenobarbital or zonisamide.](https://pubmed.ncbi.nlm.nih.gov/30238679/)

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