Animal Health
Complete medication database for dogs, cats, horses, and exotic animals — dosing, interactions, and toxicity data.
Important: Never give human medications to animals without veterinary guidance. Many human medicines are toxic or fatal to pets, even at small doses. Always consult a licensed veterinarian before medicating your pet.
280 medications in database
195 medications in database
120 medications in database
85 medications in database
Common household substances and medications that are dangerous or fatal to companion animals.
| Substance | Affects | Severity | Effect |
|---|---|---|---|
| Xylitol (artificial sweetener) | Dogs | FATAL | Causes insulin release, hypoglycemia, liver failure |
| Grapes & Raisins | Dogs | FATAL | Acute kidney failure, mechanism unclear |
| Acetaminophen (Tylenol) | Cats | FATAL | Cats lack enzyme to metabolize; causes methemoglobinemia |
| Ibuprofen / NSAIDs | Dogs & Cats | SERIOUS | GI ulceration, acute kidney failure |
| Chocolate / Caffeine | Dogs | SERIOUS | Theobromine toxicity: seizures, cardiac arrhythmias |
| Onions & Garlic | Dogs & Cats | MODERATE | Hemolytic anemia, oxidative damage to red blood cells |
| Macadamia Nuts | Dogs | MODERATE | Weakness, hyperthermia, vomiting, tremors |
| Permethrin | Cats | FATAL | Found in dog flea products; causes severe neurological toxicity in cats |
| Aspirin | Cats | SERIOUS | Cats cannot metabolize salicylates; 1 tablet can be lethal |
| Ivermectin (high dose) | Collies/MDR1 dogs | SERIOUS | MDR1 gene mutation causes medicine accumulation in brain |
If your pet may have ingested a toxic substance, act immediately.
ASPCA Poison Control
(888) 426-4435
$95 consultation fee
Pet Poison Helpline
(855) 764-7661
24/7 availability
Veterinary pharmacology presents unique challenges that distinguish it from human medicine. Unlike human pharmacy, where medicines are developed and tested for a single species, veterinary medicine must account for dramatic physiological differences across dozens of species — differences that fundamentally alter medicine pharmacokinetics and pharmacodynamics.
The liver enzymes responsible for medicine metabolism vary enormously across species. Cats famously lack glucuronyl transferase, the enzyme that metabolizes acetaminophen and aspirin in humans and dogs. This makes these common pain relievers potentially lethal to cats. Similarly, dogs and cats metabolize many medicines at different rates, requiring entirely different dosing regimens.
Horses have a unique gastrointestinal system — hindgut fermenters with a large cecum populated by billions of microorganisms. Oral antibiotics that disrupt this microbiome can cause fatal colitis, making many antibiotics (particularly penicillin given orally) extremely dangerous in horses despite being safe in other species.
One of the most clinically significant genetic variations in veterinary medicine is the MDR1 (ABCB1) gene mutation found in approximately 70% of Collies and significant percentages of Australian Shepherds, Shelties, Border Collies, and related breeds. This mutation reduces P-glycoprotein expression in the blood-brain barrier, allowing certain medicines to accumulate in the brain at toxic levels.
Medicines that must be used cautiously or avoided in MDR1-positive dogs include: ivermectin, loperamide (Imodium), acepromazine, butorphanol, vincristine, and several other common veterinary medicines. Genetic testing is available and recommended for all herding breed dogs before prescribing these medications.
Veterinary medications fall into three regulatory categories: prescription-only (Rx), over-the-counter (OTC), and veterinary feed directive (VFD) for medicated animal feeds. Many medications that require a prescription in human medicine — such as amoxicillin, prednisone, and furosemide — also require a veterinary prescription for animals in the United States.
A valid veterinarian-client-patient relationship (VCPR) is required for prescription veterinary medications. Telemedicine veterinary consultations have expanded access to this relationship, but in-person examination requirements vary by state.
Compounding plays a much larger role in veterinary medicine than in human medicine. Because medicines are rarely developed specifically for exotic species, and because palatable formulations for animals (flavored chews, transdermal gels) don't exist commercially for most medications, veterinary compounding pharmacies create customized preparations frequently.
The FDA regulates veterinary compounding but with more flexibility than human compounding, particularly for species where no commercially available product exists. However, quality standards vary significantly between compounding pharmacies.
Resistance to antiparasitic medicines is a growing crisis in veterinary medicine. Heartworm resistance to macrocyclic lactones (ivermectin, milbemycin) has been confirmed in areas of the southern United States. Gastrointestinal parasite resistance to benzimidazoles and pyrimidines is widespread in sheep, goats, and horses. Responsible antiparasitic use — including fecal egg counts to guide treatment and avoiding prophylactic use — is increasingly important.
Many human medications are used "off-label" in veterinary medicine because no species-specific formulation exists. This is legal and common when prescribed by a veterinarian, but it carries risks. Dosing must be recalculated based on the animal's weight and species-specific pharmacokinetics. Some human medications safe at human doses are toxic at equivalent weight-adjusted doses in certain species.
Antibiotics in Veterinary Medicine: Common veterinary antibiotics include amoxicillin (with or without clavulanate), enrofloxacin (Baytril, fluoroquinolone), cephalexin, doxycycline, metronidazole, clindamycin, and azithromycin. Specific antibiotics may be species-restricted — for example, enrofloxacin is approved for dogs and cats but contraindicated in young growing animals due to cartilage damage. Tetracycline antibiotics are used in many species but cause teeth discoloration in young animals.
Pain Management in Animals: Veterinary analgesia has evolved dramatically. Common options include NSAIDs specifically formulated for veterinary use (carprofen, meloxicam, deracoxib, robenacoxib, firocoxib), opioids (buprenorphine, tramadol, butorphanol, fentanyl), gabapentin (commonly used in cats for chronic pain), and amantadine. Importantly, NSAIDs approved for one species are not necessarily safe in another — for example, carprofen is approved for dogs but should not be used in cats.
Anti-Parasitic Medications: Heartworm preventives (ivermectin, milbemycin oxime, selamectin, moxidectin) protect dogs and cats. Flea/tick control products include topical (fipronil, imidacloprid, selamectin) and oral options (afoxolaner, fluralaner, lotilaner, sarolaner). Internal parasite treatments include praziquantel for tapeworms, pyrantel pamoate for roundworms and hookworms, and fenbendazole for various parasites. Resistance is an emerging concern requiring strategic use.
Cardiovascular Medications: Heart disease in pets, particularly cardiomyopathy and valvular disease, is treated with medications similar to those used in humans. Pimobendan (Vetmedin) is a cornerstone treatment for congestive heart failure. ACE inhibitors (enalapril, benazepril), furosemide, spironolactone, and digoxin are all used. Beta-blockers and calcium channel blockers have specific veterinary applications.
Endocrine Medications: Diabetes mellitus in dogs and cats requires insulin (typically vetsulin or glargine). Hyperthyroidism in cats is treated with methimazole or radioactive iodine. Hypothyroidism in dogs is treated with levothyroxine. Cushing's disease responds to trilostane or mitotane. Addison's disease requires steroid replacement.
Cats: Cats are particularly sensitive to many medications due to their unique metabolism. They lack glucuronyl transferase (cannot process acetaminophen safely), have unique sensitivity to phenolic compounds (essential oils, certain antibiotics), and require special dosing considerations for many medications. Common feline medications include methimazole (hyperthyroidism), prednisolone (not prednisone — they don't convert it well), atenolol, amlodipine, gabapentin, and various pain medications specifically suitable for cats.
Dogs: Dogs have wide variability in size (Chihuahuas vs. Great Danes), breed-specific sensitivities (MDR1 mutation in herding breeds), and species-appropriate metabolism. Common medications include heartworm preventives, flea/tick products, NSAIDs, antibiotics, allergy medications (Apoquel, Cytopoint), and behavior modification drugs.
Horses: Equine medicine faces unique challenges with the size of patients, the GI tract sensitivity, and the cost of medications at horse-appropriate doses. Common equine medications include phenylbutazone (bute), flunixin meglumine (Banamine), ivermectin/moxidectin for parasites, and various antibiotics. Racing horses face strict medication regulations.
Rabbits: Rabbits have GI flora similar to horses and are sensitive to many oral antibiotics that can cause fatal enterotoxemia. Penicillins, amoxicillin, clindamycin, lincomycin, and erythromycin are dangerous if given orally to rabbits. Safe alternatives include trimethoprim-sulfa, fluoroquinolones, and metronidazole.
Birds: Avian medicine is highly specialized with species-specific dosing for hundreds of bird species. Doxycycline is commonly used for chlamydiosis. Anti-fungals, antibiotics, and parasite treatments require careful species-specific dosing.
Reptiles: Reptile metabolism varies dramatically with temperature and species. Dosing intervals must be adjusted based on body temperature. Ceftiofur, enrofloxacin, and metronidazole are commonly used. Anesthesia and pain management in reptiles requires specialized expertise.
Pet medications can be obtained through several channels:
Be cautious of online sources that don't require veterinary prescriptions — these may be selling counterfeit or substandard products. Reputable online pharmacies will verify prescriptions with your veterinarian.
Veterinary care costs can be substantial. Strategies for managing costs include:
Veterinarians complete extensive training including 4 years of undergraduate study, 4 years of veterinary school (DVM degree), and many pursue internships, residencies, and board certification in specialty areas. The American Veterinary Medical Association (AVMA) and various state boards regulate the profession. Continuing education requirements ensure ongoing competence as veterinary medicine evolves.
Veterinary specialties include surgery, internal medicine, oncology, cardiology, dermatology, ophthalmology, neurology, dentistry, and many others. Board-certified specialists (diplomates) have additional training and experience in their specific area. Specialty referrals provide access to advanced diagnostic and treatment options.
Some human medications are used in dogs under veterinary supervision, but many are toxic. Never give human NSAIDs (ibuprofen, naproxen), acetaminophen, or antidepressants without explicit veterinary guidance. Always consult a vet before giving any human medicine to a pet.
Cats lack the liver enzyme glucuronyl transferase needed to metabolize aspirin and acetaminophen. These medicines accumulate to toxic levels causing liver failure and methemoglobinemia. Even a single regular-strength Tylenol tablet can be fatal to a cat.
The MDR1 (ABCB1) gene mutation is found in some herding breeds (Collies, Australian Shepherds, Shelties). It causes reduced P-glycoprotein in the blood-brain barrier, allowing medicines like ivermectin, loperamide, and acepromazine to accumulate in the brain at toxic levels.
Many pet medications are the same compounds as human medicines (amoxicillin, prednisone, metronidazole) but formulated in different concentrations or flavored for palatability. Some are identical to human products. The key difference is dosing — animal doses are weight-based and species-specific.