Gabapentin for Dogs: Side Effects, Risks, and What the Research Shows

If your vet just prescribed gabapentin and your dog spent the next two days sleeping through dinner, you are not imagining it. Sedation is the most common side effect of gabapentin in dogs, and it is the single thing owners ask about most. This guide covers what to expect, what is normal in the first week, what is not, when the drug should be avoided altogether, and what the published research says about dogs who were able to reduce it under veterinary care.

One thing up front: nothing here is a reason to change your dog's medication on your own. Gabapentin is a prescription drug, every dose decision belongs to your veterinarian, and one of the few genuinely dangerous things you can do is stop it abruptly. Read on for why.

What Is Gabapentin, and Why Did My Vet Prescribe It?

Gabapentin is an anticonvulsant and analgesic originally developed for people, sold under brand names including Neurontin. In dogs it is used off-label — it has never been FDA-approved for veterinary use — which is completely routine in veterinary medicine but worth understanding.

Vets reach for it in three main situations:

• Chronic and neuropathic pain — most often degenerative joint disease, osteoarthritis, intervertebral disc disease, and cancer pain. It is frequently added alongside an NSAID rather than replacing one.
• Seizures — usually as an add-on when first-line anticonvulsants are not enough on their own.
• Situational anxiety — vet visits, travel, fireworks. The American Kennel Club describes the common "chill protocol", where a dose is given the night before and again one to two hours beforehand.

It works by quieting overactive nerve signalling rather than by reducing inflammation the way an NSAID does. That mechanism is also why sedation comes with the territory.

What Is the Number One Side Effect of Gabapentin?

Sedation. Sleepiness is the most frequently reported side effect of gabapentin in dogs by a wide margin, and it is usually most pronounced in the first few days and after any dose increase.

VCA Animal Hospitals lists sedation and incoordination as the two main adverse effects and notes that they typically resolve within about 24 hours of a dose — longer in dogs with liver or kidney disease, because those organs clear the drug more slowly.

The practical question is whether the sedation is settling. Most dogs adjust within roughly a week. A dog who is still stumbling into furniture at day ten is a dog whose dose is worth revisiting with your vet.

How Does Gabapentin Make My Dog Feel?

Owners describe a fairly consistent picture. Here is what to watch for, and what each sign usually means.

Sleepy and slowed down

The most common experience: your dog sleeps more, is harder to rouse, and seems generally flat. On its own, in the first few days, this is expected. It should ease.

Wobbly on their feet

Ataxia — unsteady footing, a drunk-looking walk, difficulty on stairs or slick floors. This tends to appear at the start and again after every dose increase. Put down rugs on hard floors and help your dog on stairs while it settles.

Upset stomach

Vomiting or loose stool, usually early in treatment. Giving the dose with food or just before a meal often resolves it.

Weight gain over time

Less discussed in clinical write-ups but common in owner forums: dogs on long-term gabapentin sometimes put on weight, likely a combination of increased appetite and reduced activity from sedation. It matters more than it sounds — extra weight loads sore joints, which works directly against why the drug was prescribed.

Needing more over time

Some dogs acclimate, and a dose that worked well initially seems to do less after months. That is not automatically a sign the underlying problem is worsening, and it is a conversation for your vet rather than a reason to increase the dose yourself.

When Should Gabapentin Not Be Given to Dogs?

Gabapentin has a famously wide safety margin, which is part of why vets like it. But it is not right for every dog.

• Known hypersensitivity to gabapentin or anything it is formulated with.
• Liver or kidney disease — use with caution and usually at reduced doses, since impaired clearance makes effects last longer and hit harder.
• Pregnant or nursing dogs — safety has not been established; only under specific veterinary direction.
• Human liquid formulations containing xylitol — this one is genuinely dangerous. Some human oral solutions are sweetened with xylitol, which is toxic to dogs. Always have a veterinary formulation or a compounded version confirmed xylitol-free.
• Alongside antacids — antacids can cut gabapentin absorption by up to around 20%. Separate the doses by about two hours.
• With other sedating drugs — hydrocodone, morphine, trazodone and similar. Not forbidden, but the sedation stacks, so your vet will want to know everything your dog takes.

Never Stop Gabapentin Abruptly

This is the most important safety point on this page. Do not discontinue gabapentin suddenly, particularly in a dog being treated for seizures — abrupt withdrawal can trigger withdrawal seizures. Any reduction should be a gradual, vet-directed taper.

If you are reading this because you want your dog on less medication, that is a reasonable goal and a common one. It is also a goal that belongs to your veterinarian to manage, on a schedule.

Why Is Gabapentin Controversial for Dogs?

It is a fair question, and it comes up often enough that Google surfaces it directly. There are four honest reasons.

It is used off-label. No gabapentin product is FDA-approved for dogs. Veterinarians prescribe it on clinical judgement and the human literature, which is legal and normal but means there is no approved canine dosing on a label.

The dose range is enormous. Published veterinary guidance spans roughly 5 to 30 mg per kilogram every eight to twelve hours. A six-fold range is a sign the profession is still calibrating, and it is why two dogs of the same weight can be on very different amounts.

It is hard to separate pain relief from sedation. A quiet dog might be comfortable, or might simply be sedated. This is a real and openly debated limitation in veterinary pain management, and it is why good vets reassess rather than just continuing a prescription indefinitely.

The evidence for chronic pain is thinner than its popularity suggests. Gabapentin is prescribed very widely for canine osteoarthritis on a relatively modest evidence base. It is not alone in that — tramadol failed a placebo-controlled arthritis trial outright, which is worth knowing if your dog is on both.

None of that makes it a bad drug. It makes it a drug worth reviewing periodically with your vet rather than refilling on autopilot.

Can Dogs Take Hemp or CBD Alongside Gabapentin?

Here the advice online genuinely contradicts itself, so it is worth going to the source.

Some pet-health articles state flatly that cannabidiol should not be combined with gabapentin. Others — including VCA's drug monograph and the AKC's overview — list gabapentin's interactions without mentioning CBD at all, and the AKC notes gabapentin has few adverse interactions generally.

What the published research actually shows. The most relevant evidence comes from studies where the two were given together under veterinary supervision. A 2023 systematic review in Frontiers in Veterinary Science, Pharmacokinetics, efficacy, and safety of cannabidiol in dogs, summarised one such trial this way:

"Kogan et al. (2020) assessed the impact of CBD (0.3–4.12 mg/kg twice daily for 90 days) in association with the previous multimodal analgesic therapy (acupuncture, laser, nutraceuticals, polysulfated glycosaminoglycan, and/or gabapentin), and found that 30 out of 32 dogs showed pain relief and 21 out of 23 dogs could reduce or discontinue the administration of gabapentin."

In other words: in the trial that examined this directly, the combination was used deliberately, and over 90 days most of those dogs needed less gabapentin, not more.

The real concern is additive sedation. Both gabapentin and hemp extract can make a dog drowsy. Given together, especially early on, that effect can stack. That is a reason for your vet to start low and watch closely — which is exactly what the trial protocol did — not a reason to assume the combination is unsafe. It is also why your vet needs to know about every supplement your dog takes.

We cover what the canine literature reports about hemp and CBD tolerability in more depth in our guide to hemp and CBD side effects in dogs, and we went through the canine enzyme research drug by drug — including which medication the studies actually flagged — in our guide to CBD and your dog's medications.

What That 90-Day Trial Actually Did

Since the finding above is ours, here is the detail so you can judge it yourself rather than take our word for it.

The study was a 90-day pilot trial published in the Journal of the American Holistic Veterinary Medical Association (2020;58:35–45, DOI 10.56641/UPRM3253). It was overseen by Dr. Robin Downing, DVM, MS, DAAPM, DACVSMR, CVPP — founder of the International Veterinary Academy of Pain Management — with Lori Kogan, Ph.D. and Peter W. Hellyer, DVM of Colorado State University's College of Veterinary Medicine.

• 37 dogs enrolled with chronic maladaptive pain, primarily from osteoarthritis; 32 completed the full 90 days.
• Dogs started at 0.25 mg/kg daily and escalated at two-week reassessments; final doses ranged from 0.3 to 4.12 mg/kg twice daily.
• 30 of the 32 completers showed improved pain support; 94% of owners reported improved quality of life.
• Of the 23 dogs taking gabapentin at enrollment, 10 discontinued it and 11 reduced their dose — every change made by that dog's own veterinarian during scheduled reassessments.

The limits, stated plainly. This was an open-label pilot with no control group and no placebo arm. Dogs were on multimodal therapy, so the hemp oil was one variable among several. It is a signal worth knowing about, not proof.

Our disclosure. HempMy Pet supplied the hemp extract and reimbursed clinic costs. Per the journal's own disclosure statement, we had no input into the study design or the interpretation of results, and the authors declare no financial relationship with the company. You can read the full paper here and see our complete write-up on the clinical trials page, including a comparison of the doses used across all five published canine trials.

Questions Worth Asking Your Vet

If your dog is on gabapentin and you are unhappy with how they seem, these are productive questions:

• Is this dose still right, or is it worth reassessing now that we have seen how she responds?
• Is the sedation I am seeing expected at this dose, or is it more than you would want?
• Is she on this for pain, for anxiety, or both — and is it still doing that job?
• What would a taper look like if we ever wanted to reduce it?
• Are there other parts of her plan — weight, activity, joint support — that could carry more of the load?

Weight management and appropriate low-impact exercise do real work here, and Cornell's Riney Canine Health Center has a level-headed overview of where hemp-derived CBD currently sits in the evidence.

When to Call Your Vet Right Away

• Facial swelling, hives, or difficulty breathing — possible allergic reaction.
• Extreme sedation, collapse, or inability to stand.
• Sedation or wobbliness that is not improving after about a week.
• Persistent vomiting or diarrhea.
• Any suspected accidental overdose, or a dose given to the wrong pet.
• Seizures in a dog whose gabapentin was recently stopped or missed.

Frequently Asked Questions

What is the number one side effect of gabapentin in dogs?
Sedation. Sleepiness is the most commonly reported effect, usually strongest in the first few days and after each dose increase, and it typically eases as the dog adjusts. Incoordination is the second most common.

How does gabapentin make my dog feel?
Most dogs are sleepier and slightly unsteady at first. Some have mild stomach upset early on. After the first week most settle, and owners generally describe a calmer, more comfortable dog rather than a heavily drugged one. If your dog still seems drunk after a week, ask your vet about the dose.

When should gabapentin not be given to dogs?
Avoid it with known hypersensitivity, and use caution in dogs with liver or kidney disease or who are pregnant or nursing. Never use a human liquid formulation containing xylitol. Separate it from antacids by about two hours, and tell your vet about any other sedating medication.

Why is gabapentin controversial for dogs?
It is prescribed off-label with no FDA approval for dogs, the published dose range is very wide, it can be hard to distinguish genuine pain relief from sedation, and the evidence base for chronic pain is thinner than its popularity suggests. It remains a widely used and generally safe drug — it is just one worth reviewing periodically rather than refilling indefinitely.

Can my dog take hemp or CBD with gabapentin?
That is a question for your veterinarian, and the main thing they will weigh is additive sedation, since both can cause drowsiness. Advice online conflicts, but in the published trial that examined the combination directly over 90 days under veterinary supervision, 21 of 23 dogs on gabapentin were able to reduce or discontinue it. Never adjust a prescription yourself.

Can I stop gabapentin suddenly?
No. Stopping abruptly can cause withdrawal seizures, particularly in dogs being treated for epilepsy. Any reduction should be a gradual taper directed by your vet.

How long does gabapentin take to work in dogs?
It acts quickly, usually within one to two hours. For situational anxiety it is often given the night before and again one to two hours before the event.

If your dog's comfort is what brought you here, our hip and joint mobility range and the broader hemp for dogs collection use the same full-spectrum oil that was studied in the trial above — grown on our own Colorado farm and third-party tested every batch. Bring it up with your vet alongside everything else your dog takes.

How We Sourced This Article

Every factual claim above comes from one of the following. We have linked each one in the text so you can check it yourself.

• Kogan L, Hellyer P, Downing R. The Use of Cannabidiol-Rich Hemp Oil Extract to Treat Canine Osteoarthritis-Related Pain: A Pilot Study. Journal of the American Holistic Veterinary Medical Association. 2020;58:35–45. DOI 10.56641/UPRM3253. Full PDF. Our disclosure: HempMy Pet supplied the hemp extract and reimbursed clinic costs. Per the journal, we had no input into study design or interpretation.
• Frontiers in Veterinary Science (2023) — Pharmacokinetics, efficacy, and safety of cannabidiol in dogs: an update of current knowledge. An independent systematic review, not written by us, which restates the gabapentin finding above.
• VCA Animal Hospitals — Gabapentin drug monograph. Source for the sedation and incoordination profile, clearance in liver and kidney disease, and the antacid interaction.
• American Kennel Club — Gabapentin for Dogs. Source for the situational-anxiety protocol and the xylitol warning.
• Cornell University Riney Canine Health Center — The ABCs of CBD and hemp. Independent veterinary-school overview of where the hemp evidence currently stands.

If you find something on this page that conflicts with your veterinarian or with a source we have missed, email us at support@hempmypet.com and we will correct it. We update this article when new canine research is published.

These statements have not been evaluated by the Food and Drug Administration. Our products are not intended to diagnose, treat, cure, or prevent any disease. This article is educational and is not veterinary advice. Gabapentin is a prescription medication — never start, stop, or change your dog's dose without your veterinarian.