Quick Answer
Can Dogs Take CBD With Seizure Medication? Yes, dogs can sometimes take CBD alongside seizure medications, but only under veterinary supervision. CBD may interact with several commonly prescribed anticonvulsants—including phenobarbital, potassium bromide, gabapentin, zonisamide, and levetiracetam (Keppra). These interactions may increase sedation, affect liver metabolism, alter medication blood levels, or make it more difficult to monitor seizure control.
While early research suggests CBD may have anticonvulsant properties in some animals, there is currently insufficient evidence to recommend replacing prescription seizure medications with CBD. For dogs already receiving epilepsy treatment, the safest approach is to discuss CBD with your veterinarian before introducing any product, even those marketed as “natural.”
Why Are So Many Dog Owners Asking About CBD?
Over the last few years, CBD has become one of the most talked-about supplements in veterinary medicine.
Owners frequently wonder whether it might:
- Reduce seizure frequency
- Improve quality of life
- Reduce anxiety associated with epilepsy
- Allow lower doses of seizure medication
- Help dogs that continue having breakthrough seizures
Because epilepsy often requires lifelong treatment, many families naturally begin searching for additional options that might help their dog feel better.
Unfortunately, the internet is full of conflicting information.
Some websites claim CBD is a miracle treatment, while others warn owners never to combine it with prescription medications. The truth lies somewhere in the middle—and depends on the individual dog, the medication being used, and careful veterinary monitoring.
If you’re still learning about epilepsy treatment, our guides on Best Seizure Medication for Dogs: Complete Comparison Guide, Can Dogs Stay on Seizure Medication for Life?, and Can Dogs Miss a Dose of Seizure Medication? provide an excellent starting point.
Can Dogs Take CBD With Seizure Medication?
What Exactly Is CBD?
CBD (cannabidiol) is one of more than one hundred naturally occurring compounds called cannabinoids found in the cannabis plant.
Unlike THC (tetrahydrocannabinol), CBD does not produce the “high” associated with marijuana.
Most veterinary CBD products are derived from hemp and contain either no detectable THC or only trace amounts that meet legal limits.
CBD products marketed for dogs include:
- Oils
- Soft chews
- Capsules
- Treats
- Liquid tinctures
However, not all CBD products are manufactured to the same quality standards. The actual amount of CBD may vary significantly between brands, making veterinary guidance particularly important.
Why Are Veterinarians Concerned About Drug Interactions?
The biggest concern isn’t that CBD is inherently dangerous.
The concern is that CBD may change how other medications behave inside the body.
Many medications are broken down by enzymes in the liver before they are eliminated.
CBD can influence some of these liver enzymes, potentially causing:
- Higher medication concentrations
- Lower medication concentrations
- Increased side effects
- Unexpected changes in seizure control
This is why veterinarians are often cautious when owners mention starting CBD while their dog is already receiving anticonvulsant therapy.
Which Seizure Medications May Interact With CBD?
Not every seizure medication appears to interact with CBD in exactly the same way.
Current evidence suggests some medications deserve closer monitoring than others.
| Seizure Medication | Possible Interaction With CBD | Veterinary Concern |
|---|---|---|
| Phenobarbital | Yes | Increased sedation, liver metabolism changes |
| Potassium Bromide | Possible | Additive neurological effects |
| Levetiracetam (Keppra) | Limited evidence | Monitor response |
| Gabapentin | Possible | Increased drowsiness and coordination problems |
| Zonisamide | Possible | Limited research available |
| Diazepam | Possible | Increased sedation |
Most interactions involve additive effects on the central nervous system or changes in how medications are processed by the liver.
Our related guides Phenobarbital for Dogs, Levetiracetam (Keppra) for Dogs, Potassium Bromide for Dogs, Gabapentin for Dogs, and Diazepam for Dogs explain these medications in much greater detail.
Can CBD Increase Sedation?
Yes.
This is probably the interaction veterinarians encounter most often.
Many seizure medications already cause:
- Sleepiness
- Reduced activity
- Mild wobbliness
- Slower reactions
CBD may produce similar effects in some dogs.
When combined, these medications can occasionally lead to:
- Excessive sleeping
- Difficulty standing
- Poor coordination
- Reduced alertness
- Weakness
For some dogs this effect is mild.
For others, particularly senior dogs or those taking multiple anticonvulsants, the sedation can become significant enough to require veterinary reassessment.
If your dog already seems unusually sleepy, our articles Can Seizure Medication Cause Depression in Dogs?, Why Is My Dog Drinking More Water on Seizure Medication?, Why Is My Dog Hungry All the Time on Phenobarbital?, and Can Dogs Take CBD With Anxiety Medication? discuss several related side effects owners commonly notice.
Could CBD Affect the Liver?
This is one of the most important questions surrounding CBD use.
Both prescription seizure medications and CBD are processed by the liver.
Although most healthy dogs tolerate these substances well, combining them raises several important considerations.
Veterinarians may recommend liver monitoring because:
- Phenobarbital is metabolized extensively by the liver.
- CBD may influence liver enzyme activity.
- Some dogs require lifelong treatment.
- Existing liver disease may increase the risk of complications.
This does not automatically mean the combination is unsafe, but it does mean periodic blood testing becomes even more valuable.
Owners should never assume that a supplement is harmless simply because it is marketed as natural.
Natural products can still produce powerful biological effects.
Does CBD Change How Phenobarbital Works?
Possibly.
Phenobarbital remains one of the most effective long-term seizure medications for dogs.
Researchers are still investigating whether CBD alters phenobarbital blood concentrations or primarily affects liver metabolism.
Current evidence suggests veterinarians should monitor dogs receiving both treatments more carefully than dogs receiving phenobarbital alone.
This may include:
- Routine blood work
- Liver enzyme monitoring
- Therapeutic drug level testing
- Observation for increased sedation
- Monitoring seizure frequency
Rather than stopping either treatment, veterinarians usually adjust management based on the individual dog’s clinical response.
Is There Good Scientific Evidence That CBD Helps Dogs With Epilepsy?
This is where many internet articles become misleading.
The answer is:
There is promising research but not enough evidence to consider CBD a replacement for standard anticonvulsant therapy.
Some veterinary studies suggest CBD may reduce seizure frequency in certain dogs when used alongside conventional medications.
However, results have been inconsistent, and researchers continue investigating:
- Appropriate dosing
- Long-term safety
- Drug interactions
- Product quality
- Which patients may benefit most
For now, veterinary neurologists generally consider CBD a possible adjunctive therapy, not a first-line treatment for canine epilepsy.
Does the Type of CBD Matter?
Yes.
Not all CBD products are the same, and understanding the differences is important before giving any product to a dog taking seizure medication.
Veterinarians generally divide CBD products into three categories.
| CBD Product Type | Contains CBD | Contains Other Cannabinoids | Contains THC |
|---|---|---|---|
| CBD Isolate | ✔ Yes | ✖ No | ✖ No |
| Broad-Spectrum CBD | ✔ Yes | ✔ Yes | THC removed |
| Full-Spectrum CBD | ✔ Yes | ✔ Yes | Small legal amounts may be present |
Many manufacturers claim that full-spectrum CBD produces an “entourage effect,” where multiple cannabinoids work together.
However, from a veterinary safety perspective, products containing THC deserve extra caution.
Dogs are far more sensitive to THC than humans, and even relatively small amounts may cause serious intoxication.
For dogs already receiving anticonvulsants, veterinarians generally recommend choosing products specifically manufactured for veterinary use and discussing them before starting treatment.
Why Is THC Dangerous for Dogs?
Many owners mistakenly assume CBD and marijuana are the same thing.
They are not.
CBD itself is not considered intoxicating.
THC (tetrahydrocannabinol), however, can produce significant neurological effects in dogs.
Possible signs of THC toxicity include:
- Extreme sleepiness
- Stumbling
- Dilated pupils
- Slow heart rate
- Urinary incontinence
- Tremors
- Agitation
- Vomiting
- Coma in severe cases
These symptoms can closely resemble worsening neurological disease, making diagnosis more challenging in dogs already being treated for epilepsy.
For this reason, owners should never substitute human cannabis products for veterinary CBD products.
Can CBD Reduce the Effectiveness of Seizure Medication?
Current research has not shown that CBD consistently reduces the effectiveness of anticonvulsants.
However, because CBD may alter liver enzyme activity, veterinarians still monitor patients carefully after CBD is introduced.
Rather than assuming the medication becomes weaker, veterinarians look for changes such as:
- Increased seizure frequency
- More frequent breakthrough seizures
- Increased sedation
- Changes in appetite
- Changes in liver values
- Unexpected side effects
If seizures become more frequent after starting CBD, owners should contact their veterinarian rather than simply increasing medication doses at home.
Can CBD Help Dogs That Still Have Breakthrough Seizures?
This is one of the biggest reasons owners consider CBD.
A breakthrough seizure occurs when seizures continue despite medication.
Some dogs continue having seizures even while receiving:
- Phenobarbital
- Potassium bromide
- Keppra (levetiracetam)
- Zonisamide
- Combination therapy
Research is still ongoing, but some early veterinary studies suggest CBD may reduce seizure frequency in certain dogs.
The important word is may.
At present, CBD should be viewed as a possible adjunct therapy, not a proven replacement for conventional seizure medication.
Owners whose dogs continue having seizures despite treatment may also benefit from reading:
- Best Seizure Medication for Dogs: Complete Comparison Guide
- What to Do During a Dog Seizure
- Can Dogs Stay on Seizure Medication for Life?
- Can Dogs Miss a Dose of Seizure Medication?
These guides explain why breakthrough seizures occur and what treatment options veterinarians commonly consider.
Can CBD Be Combined With Keppra?
Compared with phenobarbital, there is less published research regarding CBD and levetiracetam (Keppra).
No major interaction has been consistently demonstrated.
Nevertheless, veterinarians generally recommend monitoring for:
- Increased sleepiness
- Changes in seizure control
- Reduced coordination
- Appetite changes
- Gastrointestinal upset
Dogs taking Keppra should continue receiving every scheduled dose exactly as prescribed.
Our article Can Dogs Miss a Dose of Seizure Medication? explains why maintaining consistent dosing is essential for seizure control.
Can CBD Be Used With Potassium Bromide?
Possibly but careful monitoring is recommended.
Potassium bromide works differently from most anticonvulsants and remains an important treatment option for many dogs with epilepsy.
Because both potassium bromide and CBD may influence the central nervous system, veterinarians monitor for additive effects such as:
- Excessive sedation
- Weakness
- Difficulty walking
- Reduced responsiveness
These effects are not inevitable, but owners should be prepared to observe their dogs closely during the first few weeks after introducing CBD.
Should Dogs Have Blood Tests After Starting CBD?
In many cases, yes.
Routine blood testing allows veterinarians to identify potential problems before they become clinically significant.
Monitoring is especially important for dogs receiving:
- Phenobarbital
- Multiple anticonvulsants
- Long-term epilepsy treatment
- CBD alongside prescription medications
Common monitoring may include:
| Test | Why It’s Helpful |
|---|---|
| Complete Blood Count (CBC) | Overall health assessment |
| Serum Biochemistry | Liver and kidney evaluation |
| Liver Enzymes (ALT, ALP, AST) | Detect medication-related liver changes |
| Phenobarbital Blood Level | Confirms therapeutic concentration |
| Electrolytes | Evaluates fluid and electrolyte balance |
| Urinalysis | Detects concurrent urinary disease |
Are Senior Dogs More Sensitive to CBD?
Often, yes.
Senior dogs may process both CBD and anticonvulsants differently because aging affects:
- Liver metabolism
- Kidney function
- Body composition
- Drug elimination
- Brain sensitivity
As a result, older dogs may experience stronger side effects even when receiving standard doses.
Veterinarians often introduce new therapies more gradually in senior patients and recommend closer follow-up during the first few weeks.
Common Owner Mistakes
Many problems arise not because CBD is inherently unsafe, but because owners unknowingly make avoidable mistakes.
Common examples include:
| Mistake | Why It’s Risky |
|---|---|
| Starting CBD without informing the veterinarian | Drug interactions may go unnoticed |
| Using human cannabis products | THC toxicity risk |
| Buying low-quality CBD online | Inaccurate labeling and contamination |
| Stopping seizure medication after starting CBD | May trigger breakthrough seizures |
| Assuming “natural” means “safe” | Natural products can still cause interactions |
| Skipping recommended blood tests | Important complications may be missed |
Avoiding these mistakes greatly improves the chances of safely integrating CBD into an epilepsy treatment plan.
Could CBD Cause Side Effects on Its Own?
Yes.
Even without other medications, CBD may occasionally cause:
- Sleepiness
- Mild gastrointestinal upset
- Decreased appetite
- Soft stools
- Temporary lethargy
Fortunately, many dogs tolerate appropriately selected veterinary CBD products well.
However, introducing CBD gradually and monitoring for changes remains the safest approach.
When Should Dogs NOT Take CBD With Seizure Medication?
Although CBD may be appropriate for some dogs with epilepsy, there are situations where veterinarians may advise against its use or recommend delaying treatment until further evaluation has been completed.
CBD should be used with particular caution in dogs that have:
- Significant liver disease
- Severe kidney disease
- Uncontrolled epilepsy
- Frequent cluster seizures
- A history of severe medication reactions
- Pregnancy or nursing
- Known sensitivity to cannabis-derived products
Likewise, dogs taking several medications simultaneously may require a more thorough review before CBD is introduced.
Veterinarians always weigh the potential benefits against the potential risks for each individual patient.
What Questions Should Owners Ask Before Starting CBD?
Before purchasing any CBD product, it’s worth discussing a few important questions with your veterinarian.
Consider asking:
- Is my dog’s epilepsy well controlled?
- Could CBD interact with my dog’s current medications?
- Should blood work be repeated before starting CBD?
- Which type of CBD product would you recommend?
- What dosage should I begin with?
- How should I monitor for side effects?
- When should I schedule a follow-up examination?
These conversations help create a safer treatment plan and reduce the likelihood of unexpected complications.
Does CBD Replace Prescription Seizure Medication?
No.
This is one of the biggest misconceptions found online.
While some websites promote CBD as a “natural alternative” to anticonvulsants, there is currently no scientific evidence supporting the routine replacement of prescription seizure medications with CBD in dogs.
Dogs with epilepsy often require carefully selected medications such as:
- Phenobarbital
- Levetiracetam (Keppra)
- Potassium bromide
- Zonisamide
- Diazepam (for emergency seizure control)
Stopping these medications without veterinary supervision can lead to:
- Breakthrough seizures
- Cluster seizures
- Status epilepticus
- Permanent neurological injury
- Death in severe cases
CBD should therefore be viewed as a possible complementary therapy, not a substitute for proven anticonvulsant medications.
Can Owners Start CBD on Their Own?
Veterinarians strongly recommend not starting CBD without discussing it first.
Although CBD products are widely available online and in pet stores, product quality varies enormously.
Some products contain:
- Less CBD than advertised
- More CBD than advertised
- Detectable THC
- Heavy metals
- Pesticides
- Residual solvents
Choosing products manufactured by reputable companies that provide third-party laboratory testing greatly reduces these risks.
How Should CBD Be Introduced Safely?
If your veterinarian believes CBD may be appropriate, it is usually introduced gradually.
A typical approach includes:
- Reviewing all current medications.
- Performing baseline blood work if appropriate.
- Selecting a veterinary-specific CBD product.
- Starting with a conservative dose.
- Monitoring closely for side effects.
- Scheduling follow-up examinations.
- Repeating laboratory tests when indicated.
Introducing only one change at a time makes it much easier to determine whether CBD is helping or causing unwanted effects.
What Symptoms Should Owners Monitor?
After starting CBD, owners should pay close attention to any changes in their dog’s behavior or health.
Monitor for:
- Increased sleepiness
- Difficulty walking
- Increased wobbliness
- Vomiting
- Diarrhea
- Appetite changes
- Increased thirst
- Increased urination
- Behavioral changes
- Any seizure activity
Keeping a seizure diary remains one of the most valuable tools for evaluating whether treatment is helping.
Record:
- Date
- Time
- Seizure duration
- Recovery time
- Any medication changes
- CBD administration
- Unusual behaviors
This information can help your veterinarian make better long-term treatment decisions.
Related Symptoms Owners Often Notice
Owners researching Can Dogs Take CBD With Seizure Medication? often search for several closely related questions, including:
- Can Seizure Medication Cause Depression in Dogs?
- Why is my dog drinking more water on seizure medication?
- Why is my dog hungry all the time on phenobarbital?
- Can dogs miss a dose of seizure medication?
- Can dogs stay on seizure medication for life?
- Why is my dog wobbly after starting seizure medication?
- Can seizure medication affect the liver?
- What should I do during a seizure?
- Can dogs take CBD with anxiety medication?
- Can dogs take gabapentin and seizure medication together?
- Best seizure medication for dogs
These related topics help owners better understand how epilepsy, medications, and supportive therapies fit together as part of a long-term treatment plan.
Veterinarian Takeaway
CBD is generating significant interest as a potential complementary therapy for dogs with epilepsy, and early research is encouraging. However, enthusiasm should be balanced with caution. CBD may interact with certain anticonvulsants particularly those metabolized by the liver and may increase sedation or complicate the interpretation of blood tests.
For most dogs, the safest approach is to continue prescribed seizure medication exactly as directed and discuss any interest in CBD with your veterinarian before introducing it. Careful product selection, gradual dosing, and routine monitoring can help minimize risks while allowing your veterinary team to determine whether CBD has a place in your dog’s treatment plan.
Bottom Line
Can dogs take CBD with seizure medication?
Sometimes but not without careful planning.
CBD may be used alongside prescription anticonvulsants in selected dogs, but it should never replace proven epilepsy treatments. Because CBD can influence liver metabolism and may increase sedation when combined with medications such as phenobarbital, potassium bromide, gabapentin, or diazepam, veterinary supervision is essential.
If you’re considering CBD for your dog, choose a high-quality veterinary product, inform your veterinarian before starting treatment, and continue monitoring your dog’s seizure control, behavior, and overall health throughout therapy.
Frequently Asked Questions – Can Dogs Take CBD With Seizure Medication
Can dogs take CBD and phenobarbital together?
Sometimes. Many veterinarians allow this combination with careful monitoring, particularly of liver function and sedation.
Does CBD interfere with seizure medication?
It may interact with certain anticonvulsants by affecting liver metabolism or increasing central nervous system depression.
Can CBD replace phenobarbital?
No. CBD should not replace prescribed seizure medication unless specifically directed by a veterinarian.
Is CBD proven to stop seizures in dogs?
Current research is promising but limited. CBD is considered a possible adjunctive therapy rather than a proven standalone treatment.
Should my dog have blood tests after starting CBD?
In many cases, yes especially if your dog is receiving phenobarbital or long-term anticonvulsant therapy.
Can CBD make my dog sleepier?
Yes. Sleepiness is one of the most commonly reported side effects and may be more noticeable when combined with seizure medications.
Is THC safe for dogs with epilepsy?
No. THC can cause serious neurological toxicity and should never be intentionally given to dogs.
Which CBD products are safest?
Veterinary-specific products from reputable manufacturers that provide third-party laboratory testing are generally preferred.
Should I stop seizure medication if CBD seems to help?
No. Never reduce or discontinue anticonvulsants without veterinary supervision.
When should I contact my veterinarian?
Contact your veterinarian if your dog develops worsening seizures, severe sedation, vomiting, weakness, difficulty walking, jaundice, or any sudden change after starting CBD.
Sources
- Plumb’s Veterinary Drug Handbook
- Merck Veterinary Manual
- BSAVA Small Animal Formulary
- Veterinary Pharmacology and Therapeutics (Papich & Riviere)
- American College of Veterinary Internal Medicine (ACVIM) Consensus Statement on Seizure Management
- International Veterinary Epilepsy Task Force (IVETF) Guidelines
- Journal of Veterinary Internal Medicine (JVIM)
- Frontiers in Veterinary Science
- JAVMA (Journal of the American Veterinary Medical Association)
- Frontiers in Veterinary Science. Cannabidiol as Adjunctive Treatment for Canine Epilepsy
- PubMed
- FDA Center for Veterinary Medicine (CVM)
Medical Review Statement
This article was written by Dimitar Georgiev Atanasov, MPharm, pharmacy and scientifically reviewed by Gergana Krasimirova Atanasova, MPharm, and independently veterinary reviewed by Dr. Valcho Georgiev Valchev, DVM. It is based on current veterinary pharmacology references, peer-reviewed scientific literature, canine epilepsy guidelines, and evidence-based veterinary recommendations. Can Dogs Take CBD With Seizure Medication?
Important Medical Disclaimer
The information provided on PetMedsMadeSimple.com is intended for educational purposes only and should not replace professional veterinary advice, diagnosis, or treatment.
Never start, stop, or change your dog’s seizure medication or CBD supplement without first consulting your veterinarian. If your dog experiences repeated seizures, collapse, severe weakness, difficulty breathing, or prolonged seizure activity, seek emergency veterinary care immediately.
Image Disclosure – Can Dogs Take CBD With Seizure Medication?
Some images used in this article may be AI-generated or AI-assisted for educational purposes. Every PMMS article is independently researched, pharmacy-written, scientifically reviewed, and veterinary-reviewed. AI-generated illustrations are used solely to improve understanding of veterinary medications and should not be interpreted as photographs of actual clinical patients.
