# Diazepam and Alprazolam Side Effects in Cats Diazepam for cats side effects are mostly sedation and unsteady movement, and they usually wear off as the drug clears. A small number of cats have the opposite reaction and become agitated or restless instead of calm. Repeated oral diazepam has also been linked to serious liver injury in cats, which is why veterinarians use it carefully and often choose other drugs for long-term anxiety treatment. This article is educational and is not a substitute for veterinary diagnosis or treatment. ## Quick Answer - Sedation and ataxia (wobbliness, staggering) are the most expected side effects of diazepam and alprazolam in cats, and they typically fade as the dose wears off. - Some cats show paradoxical excitement, meaning they become restless, vocal, or agitated instead of relaxed. - Repeated oral diazepam has been associated with liver problems in cats, so veterinarians usually avoid long-term daily diazepam and monitor liver values if it is used. - Alprazolam at 0.125 mg per cat produced sedation and anxiety reduction similar to gabapentin in two studies of cats before and after surgery [1][2]. - Never give your cat a human benzodiazepine from your own cabinet, and never change the dose on your own. Call your veterinarian or Pet Poison Helpline at (855) 764-7661 if you suspect an overdose. ## What Diazepam and Alprazolam Are and Why Veterinarians Use Them Diazepam and alprazolam belong to a drug family called benzodiazepines. They calm the nervous system by boosting the effect of a natural chemical messenger called GABA. In veterinary medicine, this family is used for anxiety, sedation before procedures, muscle relaxation, and sometimes seizure control. Diazepam has a long history in cats. It has been used to stop seizures that are happening right now, to relax tense muscles, and to reduce fear during handling. Alprazolam (often sold under the brand name Xanax in human medicine) is used more for anxiety and stress reduction. It is also a common choice for cats who panic during car rides, veterinary visits, or hospital stays. Benzodiazepines are not the only option for anxious cats. Gabapentin has become a popular alternative because it also reduces stress and sedation with a different side effect profile. You can read more about how it compares in our article on [the side effects of gabapentin for cats](/knowledge/veterinary-medicine/pet-medication-guide/gabapentin-side-effects-cats). Seizure control in cats is a separate topic with its own drug list. If your cat takes medication for epilepsy, our guide to [seizure medication side effects in cats](/knowledge/veterinary-medicine/pet-medication-guide/seizure-medication-side-effects-cats) covers what to watch for. ## How These Medicines Work in a Cat's Body Benzodiazepines attach to receptor sites in the brain and make GABA's calming signal stronger. The result is less anxiety, looser muscles, and often sleepiness. The effect starts fairly quickly after an oral dose, usually within an hour or so. The calming effect is real and measurable. In one study of cats waiting for elective surgery, a single oral dose of alprazolam reduced stress scores and increased sedation compared with a placebo [1]. A second study in cats recovering from surgery found that alprazolam and gabapentin produced similar reductions in stress, and cats given alprazolam ate significantly more food on the first day after surgery [2]. A third study found that both drugs increased sedation scores before anesthesia and reduced the amount of propofol needed for intubation [3]. That said, benzodiazepines are not a cure for anxiety. They blunt the response to a stressful event. They do not teach a cat to feel safe, and they do not fix underlying problems like pain, an unfamiliar environment, or a medical condition. Behavior plans, environmental changes, and sometimes other drug classes do that work. ## Dosing Basics for Diazepam and Alprazolam in Cats Your veterinarian decides the dose. It is calculated from your cat's weight, age, liver and kidney health, other medications, and the reason for treatment. Do not use a dose you found online, and do not adjust the amount because your cat seems more or less anxious on a given day. Diazepam can be given by mouth at home or injected in a clinic. Alprazolam is given by mouth. Both come as tablets or liquid. Some cats accept the taste, and some will drool, paw at their mouth, or hide after a dose. If your cat refuses the medication, tell your veterinarian instead of forcing it or doubling up later. If you miss a dose, give it when you remember unless it is almost time for the next one. Then skip the missed dose and go back to the normal schedule. Never give two doses at once to catch up. Do not stop a benzodiazepine suddenly if your cat has been taking it daily for more than a short period. Rebound anxiety, restlessness, and in seizure patients a return of seizures can happen. Your veterinarian will give you a tapering plan. ## Diazepam for Cats Side Effects: What Owners Actually See ### Common Side Effects Sedation is the most common effect. Your cat may sleep more, seem dull, or be slower to respond to you. Ataxia, meaning unsteady walking, is also common. Your cat may sway, drag a paw, or miss a jump. These effects usually match the peak of the drug and ease as it clears. Alprazolam produces the same general picture. in published veterinary research, sedation levels after alprazolam were similar to gabapentin and clearly higher than placebo [1][2][3]. That is expected, not a sign that something went wrong. ### Paradoxical Excitement Some cats do the opposite of what you expect. They pace, meow, seem agitated, or become more alert instead of sleepy. This is called paradoxical excitement, and it is a known benzodiazepine reaction in cats. If your cat becomes restless or distressed after a dose, stop giving the medication and call your veterinarian. A different drug or a different dose may suit your cat better. ### Liver Concerns With Repeated Diazepam This is the side effect that matters most for long-term use. Repeated oral diazepam has been associated with liver injury in cats, and it can be severe. Because of this risk, veterinarians generally avoid daily oral diazepam for weeks or months and prefer other medications for chronic anxiety. If diazepam is used repeatedly, your veterinarian may check liver blood values before and during treatment. Liver problems can also change how a cat handles these drugs. In one report, a cat with a portosystemic shunt (a liver blood flow abnormality) received intravenous diazepam for seizures and then developed worsening neurological signs, including head pressing, loss of menace response, and a stuporous state. Flumazenil, a drug that reverses benzodiazepine effects, produced immediate but temporary improvement [4]. This is a reminder that liver function and benzodiazepine handling are tightly linked. ### Side Effect Table | Side effect | How common or serious | What to do | |---|---|---| | Sedation, sleepiness | Common, usually mild to moderate | Let your cat rest in a quiet, safe space. Do not leave them on high furniture or stairs. | | Ataxia (wobbling, staggering) | Common, usually mild to moderate | Block stairs, keep food, water, and litter box on one level. Call your vet if it is severe or lasts longer than expected. | | Increased appetite | Reported with alprazolam after surgery [2] | Expected in some cats. Do not free-feed if your cat has a weight or diabetes problem. | | Paradoxical excitement (pacing, vocalizing, agitation) | Uncommon but recognized | Stop the medication and call your veterinarian the same day. | | Vomiting, drooling, lip smacking | Uncommon, often linked to taste | Offer water. Tell your vet if it happens with every dose. | | Liver injury with repeated oral diazepam | Uncommon but serious | Report yellow gums, vomiting, lethargy, or loss of appetite right away. Blood work may be needed. | | Severe sedation, collapse, trouble breathing | Rare, emergency | Go to a veterinary emergency clinic now. | ## Alprazolam for Cats Side Effects Alprazolam side effects in cats overlap heavily with diazepam. Expect sedation and some wobbliness, especially in the first hours after a dose. In the hospital studies, alprazolam was well tolerated overall, and the main observed effect was sedation comparable to gabapentin [1][2][3]. Alprazolam is sometimes chosen over diazepam because it is less tied to the liver injury concern with repeated oral dosing. That does not make it risk-free. Any benzodiazepine can cause excessive sedation, and any cat can have an unusual reaction. Cats with liver disease, kidney disease, or a history of a bad reaction to a benzodiazepine need a careful conversation with their veterinarian before starting. If your cat takes alprazolam for anxiety, pair it with a plan. Medication works best alongside changes to the environment, a predictable routine, and treatment of any pain or medical problem that is driving the stress. Our article on [cat allergy medication side effects](/knowledge/veterinary-medicine/skin-allergy-and-ear-care/cat-allergy-medication-side-effects) is a useful reminder that many "behavior" problems in cats have a physical trigger underneath. ## Who Should Not Take These Medicines, and What Interacts With Them Cats with significant liver disease are poor candidates for diazepam, especially repeated oral doses. Cats with severe kidney disease, heart disease, or breathing problems also need extra caution because sedation can worsen their condition. Benzodiazepines add to the effects of other sedating drugs. That includes opioids, other benzodiazepines, alpha-2 agonists used in clinics, and some anesthetics. In the anesthesia studies, pretreatment with alprazolam or gabapentin increased sedation and lowered the propofol dose needed for intubation [3]. That is useful in a controlled hospital setting, but it also shows how strongly these drugs stack with other sedatives. Never combine your cat's prescription with a human sedative, sleep aid, antihistamine, or anxiety medication unless your veterinarian specifically tells you to. Never give a benzodiazepine prescribed for another pet or another person. Tell your veterinarian about every product your cat receives, including supplements, flea and tick products, and herbal remedies. Also mention if your cat is pregnant, nursing, or has a known portosystemic shunt. ## Overdose and When to Call for Help Signs of overdose include extreme sedation that you cannot rouse your cat from, weak or unsteady breathing, collapse, muscle twitching, or a body temperature that feels low. These are emergencies. If you think your cat ate too much diazepam or alprazolam, or got into a human pill bottle, call Pet Poison Helpline at (855) 764-7661 and go to a veterinary clinic right away. Treatment depends on how much was taken and how severe the signs are. Mild cases may need fluids and monitoring until the drug wears off, while severe cases may need hospitalization and medication to reverse the effects [5]. Bring the pill bottle or packaging with you if you can. Knowing the drug name, strength, and how many tablets are missing helps the veterinarian act faster. ## Limitations and When to Contact a Veterinarian Every cat responds differently, and only your veterinarian can judge your cat's specific situation. The guidance below is a starting point, not a diagnosis. Call your veterinarian the same day if your cat: - Becomes agitated, restless, or more anxious after a dose - Vomits repeatedly or refuses food and water - Seems more wobbly than expected or cannot walk steadily - Has a dose change, a missed dose, or a new medication added Go to an emergency clinic now if your cat: - Cannot be woken up - Breathes slowly, weakly, or with effort - Collapses or has a seizure - Has yellow gums, yellow eyes, or a swollen belly (possible liver problem) - May have eaten a large number of pills Schedule a routine visit if your cat: - Needs a refill or a dose adjustment - Has been on daily benzodiazepines and you want to stop - Is not improving on the current anxiety plan - Needs liver or kidney blood work before or during treatment ## Frequently Asked Questions ### How long do diazepam side effects last in cats? Most sedation and wobbliness ease as the drug clears, often within several hours for a single dose. The exact timing depends on the dose, your cat's liver function, and other medications on board. If your cat is still heavily sedated the next day, call your veterinarian. ### Can I give my cat my own Xanax? No. Human alprazolam products are dosed for people, and the tablet strength is far too high for most cats. Giving your own medication can cause severe sedation, collapse, and breathing problems. Call your veterinarian or Pet Poison Helpline at (855) 764-7661 if this has already happened. ### Is diazepam safe for cats with seizures? It can be used to stop a seizure that is happening, and it has a role in some emergency seizure protocols. It is generally not a good choice for daily long-term seizure prevention in cats because of the liver concern with repeated oral dosing. Your veterinarian will pick a maintenance seizure drug based on your cat's full health picture. ### Why did my cat get hyper instead of sleepy? This is paradoxical excitement, a known benzodiazepine reaction in cats. It does not mean you did anything wrong, and it does not always mean the drug is unsafe. Stop the medication and call your veterinarian, who may switch to a different drug class. ### Can my cat take diazepam or alprazolam every day? Short courses are common, and some cats do take benzodiazepines regularly under veterinary supervision. Daily oral diazepam raises liver concerns over time, so many veterinarians choose a different drug for long-term anxiety. If your cat is on a daily benzodiazepine, ask about monitoring and about a plan to taper safely. ## Related Articles - [What Are the Side Effects of Seizure Medication in Cats?](/knowledge/veterinary-medicine/pet-medication-guide/seizure-medication-side-effects-cats) - [What Are the Side Effects of Apoquel for Cats?](/knowledge/veterinary-medicine/pet-medication-guide/apoquel-side-effects-cats) - [What Are the Side Effects of Gabapentin for Cats?](/knowledge/veterinary-medicine/pet-medication-guide/gabapentin-side-effects-cats) - [Cat Allergy Medication Side Effects: What to Watch For](/knowledge/veterinary-medicine/skin-allergy-and-ear-care/cat-allergy-medication-side-effects) - [Cat Urinary Tract Infection Side Effects](/knowledge/veterinary-medicine/clinical-methods/cat-urinary-tract-infection-side-effects) - [Gabapentin For Cats](/knowledge/veterinary-medicine/clinical-methods/gabapentin-for-cats) - [Alprazolam for Cats: Uses, Safety, and What It Does](/knowledge/veterinary-medicine/pet-medication-guide/alprazolam-for-cats-uses) - [Diazepam for Cats: Dosage, Uses, and Safety](/knowledge/veterinary-medicine/pet-medication-guide/diazepam-for-cats-dosage) - [Diazepam as an Appetite Stimulant for Cats: Does It Work?](/knowledge/veterinary-medicine/pet-medication-guide/diazepam-appetite-stimulant-cats) ## References 1. [Orally administered gabapentin and alprazolam induce comparable levels of anxiolysis and sedation in cats](https://pubmed.ncbi.nlm.nih.gov/38503044/). Journal of the American Veterinary Medical Association, 2024. 2. [Use of Gabapentin or Alprazolam in Cats during Postoperative, Short-Term Hospitalization](https://pubmed.ncbi.nlm.nih.gov/38997952/). Animals : an open access journal from MDPI, 2024. 3. [Gabapentin and alprazolam pretreatment enhance sedation and reduce propofol requirements but do not improve intravenous catheter placement in cats undergoing elective ovariohysterectomy](https://pubmed.ncbi.nlm.nih.gov/39813800/). Journal of the American Veterinary Medical Association, 2025. 4. [Flumazenil Treatment for Diazepam-Associated Neurological Signs in a Cat With a Portosystemic Shunt](https://pubmed.ncbi.nlm.nih.gov/37619774/). Topics in companion animal medicine, 2023. 5. [Clonazepam for Cats](https://www.petpoisonhelpline.com/uncategorized/clonazepam-for-cats/). Pet Poison Helpline. ## Further Reading - [Xanax and Cats (Pet Poison Helpline)](https://www.petpoisonhelpline.com/uncategorized/xanax-and-cats/) - [American Veterinary Medical Association: First Aid Tips for Pet Owners](https://www.avma.org/resources-tools/pet-owners/emergencycare/first-aid-tips-pet-owners) - [Merck Veterinary Manual: Cat Owners](https://www.merckvetmanual.com/cat-owners)