The most common medications, what they do, and what to ask at your next appointment.
When your vet hands you a bottle of amoxicillin and tells you to give one tablet twice daily for seven days, most owners just do it. But understanding why your pet is on a particular drug, what side effects to watch for, and what the full course requires makes you a much better carer — and helps you catch problems early if something isn't right.
This guide covers the most commonly prescribed veterinary medications for dogs and cats. It's not a substitute for veterinary advice. It's background knowledge that helps you ask better questions.
A broad-spectrum penicillin-type antibiotic. Used for skin infections, urinary tract infections (UTIs), respiratory infections, and wound infections. Available in tablet, capsule, or liquid form. Typical dose is 11–22 mg/kg twice daily.
Side effects are usually mild — occasional vomiting or diarrhoea. Give with food to reduce stomach upset. Completing the full course is important to prevent antibiotic resistance, even if your pet seems better after a few days.
Not suitable for animals with penicillin hypersensitivity (rare but possible). Cats tolerate it well; dogs similarly.
Amoxicillin combined with clavulanate, which blocks the enzyme some bacteria use to break down the antibiotic. Broader spectrum than amoxicillin alone — effective against bacteria that have developed resistance to standard amoxicillin. Commonly prescribed for deep skin infections (pyoderma), bite wounds, and dental infections.
Vomiting and diarrhoea are more common than with plain amoxicillin. Give with food. Typical course is 5–10 days.
A cephalosporin antibiotic — related to penicillins but structurally different, and active against some bacteria that resist amoxicillin. Very commonly used for skin infections, particularly recurring bacterial skin disease (superficial pyoderma) in dogs. Cats use it less frequently.
Typical dose: 22–30 mg/kg twice daily. Long courses (4–6 weeks) are common for deep skin infections. Gastrointestinal side effects are the main concern.
A tetracycline antibiotic. Used for atypical respiratory infections (kennel cough), Lyme disease and other tick-borne infections (Ehrlichia, Anaplasmosis), and some skin conditions. Also used in cats for chlamydophila (a cause of eye disease) and mycoplasma.
Important for cats: doxycycline can cause oesophageal strictures if it lodges in the oesophagus. Always give with water and food, and follow with a syringe of water. In dogs, give with a full meal to prevent oesophageal irritation.
An antibiotic and antiprotozoal agent. The go-to treatment for gut infections, giardia, and diarrhoea with suspected bacterial causes. Often used after gastrointestinal surgery. Can also help with inflammatory bowel conditions.
Side effects include nausea and neurological signs at high doses (wobbliness, head tilt). Typical dose is 10–20 mg/kg once or twice daily. Generally safe in cats; give with food.
A non-steroidal anti-inflammatory drug (NSAID) for dogs. Used for arthritis, post-surgical pain, and soft tissue pain. Very commonly prescribed and generally well-tolerated. Typical dose: 4.4 mg/kg once daily, or 2.2 mg/kg twice daily.
Important: Never give carprofen (or any NSAID) to cats. Cats are highly sensitive to NSAID toxicity due to different metabolic pathways. In dogs, long-term use requires periodic liver and kidney monitoring. Always give with food.
Another NSAID — used in both dogs and cats. Cats can receive meloxicam at very low doses for short-term pain management (e.g., post-surgery), though long-term use in cats remains controversial due to kidney effects. Dogs typically use it at 0.2 mg/kg on day one, then 0.1 mg/kg once daily.
Do not combine NSAIDs (e.g., don't give meloxicam and carprofen together). Do not give with steroids (e.g., prednisolone). A washout period is required when switching between NSAIDs and steroids.
A corticosteroid. Used to reduce inflammation in a wide range of conditions: allergic skin disease, immune-mediated conditions, inflammatory bowel disease, respiratory conditions, and as part of cancer treatment protocols. Very effective at reducing inflammation quickly.
Side effects at higher doses include increased thirst, urination, and appetite, as well as potential effects on the immune system, adrenal glands, and long-term organ health. Never stop prednisolone suddenly after long-term use — must be tapered. Cannot be given at the same time as NSAIDs.
An opioid-type pain reliever used in dogs for moderate to severe pain. Often prescribed for post-surgical pain or advanced arthritis where NSAIDs alone are insufficient. Typical dose: 2–5 mg/kg two to three times daily.
Not recommended for cats in the UK due to very short duration of effect and unpleasant taste in most formulations.
A proton pump inhibitor that reduces stomach acid production. Prescribed for gastric ulcers, acid reflux, oesophagitis, and to protect the stomach lining during NSAID treatment. Give 30 minutes before feeding for best effect.
Typical dose for dogs: 0.5–1 mg/kg once daily. Used in cats too, though usually at a lower end of the range.
An H2 blocker — a gentler acid reducer than omeprazole, and sometimes preferred for short-term or mild stomach upset. Available over the counter in human formulations (Pepcid) but dosing for pets differs from human dosing.
Typical veterinary dose for dogs and cats: 0.5–1 mg/kg once or twice daily. Always confirm the dose with your vet — the human tablet strength may not match what's appropriate for your pet's weight.
A broad-spectrum dewormer. Effective against roundworms, hookworms, whipworms, and giardia. Available as granules or paste. Typically given for 3–5 days for standard worm treatment; a longer 5-day course is used for giardia.
Generally very safe and well-tolerated in both dogs and cats. Rarely causes vomiting. Pregnant animals can be treated, making it useful in breeding situations.
Some human medications are used in veterinary medicine, but at very different doses and not always in both species. Others are directly toxic:
If your pet has ingested any human medication, contact your vet or an emergency animal poison line immediately.