Several over-the-counter drugs can be used for pets, but I wouldn’t advise giving your cat or dog any of these medications before checking with your vet. Some drugs that are okay for dogs are not suitable for cats and vice versa. You'll also have to calculate the appropriate dosage to use, an amount that usually depends on the animal’s weight.
While researching your question, I found a useful chart listing the over-the-counter drugs deemed safe for pets at the website of the Walker Valley Veterinary Hospital in Walker Valley, N.Y. In addition to differences between cats and dogs, some medications are unsafe for particular breeds. Here’s a summary of the information on the chart:
- Imodium (loperamide): Can be given to some dogs and cats for diarrhea. However, adverse reactions may occur in collies, shelties, Australian shepherds and long-haired whippets. Do not give Imodium to any of these breeds.
- Benadryl: An antihistamine that helps relieve swellings and itching from allergic reactions and is used long-term to treat allergies. The dose is one milligram for every pound, given twice daily. (Although safe for cats, Benadryl doesn’t work very well for them. If your cat has allergy symptoms, ask your vet for an appropriate antihistamine.)
- Aspirin: For inflammation and pain, aspirin can be given short-term to dogs (never give aspirin to cats!) Buffered aspirin (Bufferin) is easier on the stomach but regular (non-coated) aspirin can also be used. Give aspirin once or twice a day, always with food. Continued usage may be dangerous in some animals. For long-term pain relief ask your vet for alternatives.
- Dramamine (Dimenhydrinate): An antihistamine that prevents motion sickness in cats and dogs. Give it at least a half an hour before travel. The dosage depends on the weight of the animal. Ask your vet for guidance.
- Tagamet (Cimetidine) /Pepcid-AC (Famotidine) /Zantac (Ranitidine): These drugs reduce the amount of stomach acid in dogs and cats with ulcers, acid reflux or belly ache. They are sometimes used to prevent ulcers in pets taking other medications. Check with your vet for dosage information.
- Hydrocortisone: Cream or ointment that can be used on the skin to reduce itching from hives, hot spots, and insect bites and stings. Apply a small amount up to two times daily.
- Gas-X (Simethicone): For dogs with unusual flatulence or gas discomfort. Any dog suspected of having bloat, a life-threatening condition that requires emergency veterinary care, should get two doses immediately and then be taken to the vet.
- Glucosamine: Used in combination with chondroitin sulfate to reduce the pain of arthritis. This is a long-term treatment - effects may not be immediately noticeable.
In addition to the drugs listed above, antibiotic ointments can be used to treat small wounds, bites or minor infection. Before use, thoroughly clean the wound with soap and water. You can use antibacterial soap to clean any wound or injury. It is safe to give dogs one to 10 teaspoons of hydrogen peroxide to induce vomiting but never do this except with your vet’s advice. If you think your pet may have eaten something poisonous, call the ASPCA’s Animal Poison Control Center at 888-426-4435. You can use saline nasal spray and pediatric nasal sprays to relieve dryness and nasal congestion associated with colds in kittens, cats, puppies, and dogs. Don’t use any other over-the-counter nasal spray unless prescribed by your veterinarian.
Andrew Weil, M.D.