When it comes to pet health, there seem to be many medication options for treating illnesses and managing chronic conditions—including drugs originally manufactured for humans. 

It’s not uncommon for human medicine to be used for pets. Federal law allows veterinarians to prescribe drugs that were labeled for human use under certain conditions in animals, which is referred to as extra-label use. 

Often, these medications are easier to access, cost less, seem safe, and have swaths of information published about them. But for those same reasons, they can pose a danger to pets, according to Alisa Craig, director of Pharmaceutical Services at the University of Minnesota Veterinary Medical Center.

“Human safe does not always mean pet safe,” Craig says. “Just because you think, ‘This is safe for me,’ doesn't always mean that it's safe for your pet.”

Defining differences

While medications may treat or manage some of the same illnesses in humans and pets, there are differences that can have significant impacts on how these drugs function or are administered. 

Breaking it down: One of these factors is metabolism, which in this case refers to the breakdown of drugs by the digestive system. As humans, we stand upright and have vertical digestive tracts. On the other hand, most of our pets have a horizontal digestive tract, and that impacts how they metabolize drugs. 

For example, Craig notes that the commonly used human antibiotic Ciprofloxacin (Cipro®) can be absorbed by the gastrointestinal tract in its active form—the form that provides desired therapeutic effects—by humans, but pets are unable to do so. Instead, animals are given Enrofloxacin (Baytril®), which is then broken down in the body into the Ciprofloxacin. However, if a human were to take Enrofloxacin, the drug could cause neurological and cardiovascular issues such as seizures and heart problems, she says.

Ingredients issues: Many human medications also have extra ingredients that can be toxic to animals. One example is xylitol, which is often used as a sweetening agent in food and pharmaceutical production. It’s highly toxic to pets. 

“We have human medications in our pharmacy, and whenever we get a new product, we will always look to see and make sure that xylitol is not in that product,” Craig says. 

Some medications also have hidden flavorings that cats and dogs might react to, with Craig noting that they do not like cherry and berry. 

Species considerations: Cats and dogs may seem similar, but their medication and doses are not interchangeable. 

“Most drugs break down in the kidney and liver, and so in cats, in particular, liver enzyme pathways are limited, and they can't break down drugs as easily as you or I or even dogs,” Craig says.

Cats also have hypersensitivity to substances such as oils, natural compounds, and pain medications, as well as a heightened sense of taste when it comes to bitterness that can impact their willingness to take medication. 

Some dog breeds—such as collies, shepherds, and sheepdog varieties—carry a mutated gene that causes sensitivities to deworming and antiparasitic drugs. 

Medication considerations

Before opening up the medicine cabinet or purchasing OTC medications for pets, Craig offers guidance that prioritizes the safety and health of pets.  

First and foremost, always consult a veterinarian and never dose without a professional’s guidance on safety and efficacy. Medication dosage is determined by a pet’s weight, but health and age also can impact a medication’s effectiveness. For example, the older a pet is, the slower they break down drugs, which can increase the risk for toxicity. 

And while human medications can work in a pinch, it is best to use medicine tailored for animals whenever possible. 

“When it comes to picking an over-the-counter product, if there are veterinary-specific products that are out there, I would choose—and always choose—the veterinary-specific formula over a human over-the-counter alternative,” Craig says. 

Additionally, she advises that her golden rule is when in doubt, wait for a professional recommendation. 

And as helpful as properly administered human medications may be, these drugs should be used to support and not replace veterinary care. 

Watch Alisa Craig’s Animal Health Education Series webinar “Medicating Pets Safely: A Guide to OTC Drugs for Dogs and Cats” for more information. The Animal Health Education Series is a virtual event series led by expert clinicians and researchers from the University of Minnesota College of Veterinary Medicine and its Veterinary Medical Center.

Recommendations for OTC medications 

While the following over-the-counter medications are among the safer options for home care, they should never be administered without the prior approval of a veterinarian. Your veterinarian must evaluate your pet’s specific health profile to provide a safe, weight-based dosage and ensure the product doesn't contain hidden, harmful additives.  Consulting a professional is the only way to guarantee that a simple remedy remains a safe one. 

Allergies and itching

• Diphenhydramine (Benadry®): Can be used for bee stings and sudden allergic reactions
• Chlorpheniramine (Chlor-Trimeton®): Considered the gold standard in cats for allergies
• Loratadine (Claritin®): Can be used for seasonal allergies; do not use D or long-acting products
• Cetirizine (Zyrtec®): Can be used for itchy skin, allergies
• Hydrocortisone 1% cream: Can be used for itchy/hot spot skin; use sparingly (not for more than seven days) and prevent your pet from licking the treatment area.

Gastrointestinal (GI) support

• Famotidine (Pepcid AC®): Can be used for acid reflux or "empty stomach" bile vomiting
• Dimenhydrinate (Dramamine®–classic): Can be used for motion sickness
• Omeprazole (Prilose®): Well tolerated by patients with inflammation in the esophagus and ulcers.
• Loperamide (Immodium®): Can be used for diarrhea, but is dangerous in collies, Shetland sheepdogs (shelties), Australian shepherds, old English sheepdogs, English shepherds, German shepherds, long-haired whippets, and windhounds due to a genetic mutation.
• Plain pumpkin: Plain pumpkin (not pumpkin pie mix) is a natural OTC for both constipation and diarrhea in moderation. No more than 2 tbsp per day unless advised by a veterinarian. 

First Aid (Topical treatments—use sparingly and prevent your pet from licking)

• Neosporin topical: An antibiotic that can be used for minor scrapes. Avoid Plus versions with additional ingredients like lidocaine or other antibiotics.
• Saline eye drops: A topical solution that can be used for flushing out debris; must be plain saline (sodium chloride)
• Gel lubricants (not petroleum-based products)