By Dr. Michelle Frye, DVM · Published 2026-05-01
TL;DR. Prednisolone (preferred in cats) and prednisone are corticosteroids used for allergies, immune-mediated disease, IBD, asthma, and certain cancers. Anti-inflammatory dose: 0.5–1 mg/kg/day. Immunosuppressive dose: 2–4 mg/kg/day. Never combine with NSAIDs. Never stop suddenly after long-term use — taper.
The Drug Owners Both Love and Hate
It is impossible to practice small-animal medicine without prednisolone. It is also impossible to practice it without occasionally cursing prednisolone. The same drug that quiets a flaring autoimmune disease in 24 hours is the one that turns a 30-pound cocker into a barrel and a 12-year-old cat into a serial litter-box-flooder. The trick is knowing which of those trade-offs is worth it for your particular pet, at this particular moment.
What Prednisolone Actually Does
Prednisolone is a synthetic glucocorticoid that mimics the body's own cortisol — suppressing inflammation broadly and dampening overactive immune responses. Cats convert prednisone to its active form (prednisolone) less efficiently than dogs do, which is why prednisolone is the preferred form for cats. In dogs, both work fine.
- Anti-inflammatory dose: 0.5–1 mg/kg once daily.
- Immunosuppressive dose: 2–4 mg/kg once daily, typically tapered over weeks to months.
- Onset: hours. Anti-inflammatory effect is often visible within the first day.
- Half-life: short, but biological effects last 12–36 hours, allowing once-daily dosing.
Things People Are Wrong About
Myth 1: "Steroids are bad and should be avoided." Steroids are extraordinary, life-saving drugs. They are also blunt instruments. The right steroid for the right disease at the right dose for the right duration is exactly what you want. Reflexive avoidance costs lives.
Myth 2: "My dog is on prednisone so I can give carprofen for the limp." No. NSAID + steroid is the single most preventable cause of GI ulcers in companion animals. Pick one. A washout period is required to switch.
Myth 3: "Prednisone makes him pee and drink, that's just how it is." Yes — at the immunosuppressive dose. As the dose tapers down, those side effects fade. Bathroom-flooding is not the long-term reality for most patients.
Myth 4: "I'll just stop when he seems better." Long-term steroid use suppresses the body's own cortisol production. Stopping abruptly can trigger an iatrogenic Addisonian crisis. Always taper under veterinary direction.
When NOT to Use Prednisolone
Avoid concurrent use with NSAIDs (carprofen, meloxicam, Galliprant, Onsior, Rimadyl) — the GI ulcer risk is enormous. Use cautiously in pets with diabetes (steroids worsen control), congestive heart failure, hypertension, and active untreated infections (steroids can worsen them). Pregnant pets should not receive steroids except in true emergencies. Never stop a long-term course suddenly.
What I Tell Owners After 30 Years
The fear of steroids is bigger than the actual risk for most uses. The danger is not in the drug itself — it is in using it as a long-term crutch when a more targeted therapy (Apoquel, Atopica, an immunosuppressant) would do the same job with fewer trade-offs. Use prednisolone aggressively for the acute crisis. Use it sparingly, and with a plan to taper, for chronic disease. And never, ever combine it with an NSAID.
Frequently Asked Questions
What is the difference between prednisone and prednisolone?
Prednisone is converted to its active form (prednisolone) in the liver. Cats convert prednisone less efficiently, so prednisolone is the preferred form for cats. In dogs, both forms work essentially the same.
How long does prednisolone take to work?
Anti-inflammatory effects are often visible within hours of the first dose, with full effect in 24–48 hours.
What are the side effects of prednisolone?
Increased thirst, urination, hunger, panting, and weight gain are most common. Long-term use can cause muscle wasting, thinning skin, secondary infections, iatrogenic Cushing's, GI ulceration, and diabetes.
Can my dog take prednisone with carprofen or other NSAIDs?
No. The combination dramatically increases the risk of stomach ulcers and kidney damage. A washout period is required when switching between an NSAID and a steroid.
How do I taper prednisolone safely?
Always follow the schedule your veterinarian provides. Generally, dose is reduced by 25–50% every 1–2 weeks, depending on the disease and response. Never stop suddenly after more than 2–3 weeks of therapy.
Will prednisolone make my cat diabetic?
Long-term high-dose steroid use can cause diabetes, especially in cats. Lower doses, shorter courses, and disease alternatives (Atopica for skin disease, dietary changes for IBD) reduce that risk.
Can I give prednisolone with food?
Yes. Giving with food reduces GI upset and is generally recommended.
Where can I buy prednisolone for my pet?
Prednisolone is prescription-only. Smarty Vets dispenses prednisolone, prednisone, and pharmacy-compounded oral liquids from a licensed pharmacy.
This article is for educational purposes and is not a substitute for veterinary advice. Always consult your veterinarian before starting, stopping, or changing any medication for your pet.