Vet Guide to Aspirin (Acetylsalicylic Acid) in 2025 🐾

Hi, I’m Dr Duncan Houston, BVSc — founder of Ask A Vet. This in-depth guide explores aspirin’s off-label use in dogs and its rare, cautious use in cats. We'll cover its mechanism, proper dosing, side effects, monitoring, interactions, and when to seek veterinary support. Let’s dive in! 🩺

📘 What Is Aspirin?

Aspirin (acetylsalicylic acid) is a classic non-steroidal anti-inflammatory drug (NSAID) that inhibits COX-1 and COX-2 enzymes irreversibly to reduce pain, fever, inflammation, and platelet aggregation :contentReference[oaicite:3]{index=3}. Though FDA-approved for humans, it is used **off-label** in veterinary medicine ⚕️ :contentReference[oaicite:4]{index=4}.

✅ Veterinary Uses in 2025

• Pain relief for mild-to-moderate osteoarthritis in dogs when safer NSAIDs aren't available :contentReference[oaicite:5]{index=5}
• Anti-platelet use in thromboembolic conditions like protein-losing enteropathy in dogs (10 mg/kg every 48 hrs) :contentReference[oaicite:6]{index=6}
• Rare, strict-use in cats (10 mg/kg every 48 hrs) for antiplatelet needs, under strict veterinary supervision :contentReference[oaicite:7]{index=7}

📐 Dosing Guidelines

🐶 Dogs

• Pain/inflammation: 10–40 mg/kg orally every 8–12 hrs—use lowest effective dose; short-term only :contentReference[oaicite:8]{index=8}
• Anti-clot therapy: 10 mg/kg every 48 hrs :contentReference[oaicite:9]{index=9}

🐱 Cats

• Very cautious use only when prescribed by a vet: 10 mg/kg every 48 hrs — cats lack glucuronidation, so dosing must be spaced to avoid toxicity :contentReference[oaicite:10]{index=10}

Always follow your veterinarian’s tailored dosing plan and avoid long-term use without supervision.

⚠️ Safety & Side Effects

Common (dogs):

• GI upset: vomiting, diarrhea, ulcers—common with prolonged use :contentReference[oaicite:11]{index=11}
• Increased bleeding risk due to platelet inhibition

Common (cats/rare):

• Same GI risks, plus risk of salicylate build-up—vomiting, bleeding, coordination loss, respiratory distress :contentReference[oaicite:12]{index=12}

Serious (dogs and cats):

• Ulceration, GI hemorrhage, perforation
• Toxic overdose: seizures, coma, acidosis, organ damage :contentReference[oaicite:13]{index=13}

🩺 Monitoring & Follow-Up

• Short-term pain use—monitor for appetite loss, vomiting, melena
• Antiplatelet use—check platelets, kidney & liver enzymes every 2–4 weeks
• For long-term use: CBC, blood chem, and urinalysis every 4–8 weeks :contentReference[oaicite:14]{index=14}
• Any sign of GI bleeding or clotting issues → stop and contact your vet immediately

🔗 Drug Interactions

• Do **not** combine with other NSAIDs (carprofen, meloxicam) – bleeding risk skyrockets :contentReference[oaicite:15]{index=15}
• Careful with corticosteroids, SSRIs, anticoagulants, and diuretics
• Aspirin can reduce effects of spironolactone; watch interactions with warfarin or methotrexate :contentReference[oaicite:16]{index=16}

⏳ Missed Dose or Overdose?

• Missed dose: skip and resume next scheduled dose—**do not double** :contentReference[oaicite:17]{index=17}
• Overdose—watch for vomiting, bleeding, seizures, tremors. Contact your vet or Pet Poison Helpline (855‑764‑7661) immediately :contentReference[oaicite:18]{index=18}

🏡 Real-Life Treatment Examples

🐶 Dog with Painful Arthritis

• Start 10 mg/kg BID short-term (3–5 days) with food
• Monitor stool and appetite; switch to safer NSAID if needed

🐶 Dog with Thromboembolic Risk (e.g. PLE)

• Give 10 mg/kg every 48 hrs; check platelet function and GI signs biweekly

🐱 Cat with Antiplatelet Need

• Only 10 mg/kg every 48 hrs, prescribed and monitored by a vet
• Cats must be closely watched for toxicity—stop if GI or neurologic signs appear

❓ Frequently Asked Questions

Is aspirin safe for my dog?

Short-term (<7 days) and at correct doses it can be, but safer veterinary NSAIDs are preferred for most cases :contentReference[oaicite:19]{index=19}.

Can I give human baby aspirin?

Only if directed by your vet. Human aspirin products may contain additives unsuitable for pets.

Why space doses 48 hrs in cats?

Cats lack the glucuronidation pathway, making metabolism slow—spacing doses reduces toxicity risk :contentReference[oaicite:20]{index=20}.

Why not use long-term?

Long use sharply increases risks of ulcers, bleeding, and organ damage—veterinary NSAIDs are safer alternatives.

📌 Final Takeaways

• Aspirin is a classic NSAID used off-label in pets for mild pain, inflammation, or clot prevention.
• 🐶 Dogs: 10–40 mg/kg every 8–48 hrs depending on purpose; short-term pain vs longer-term clot control.
• 🐱 Cats: rare, 10 mg/kg every 48 hrs with strict monitoring due to slow metabolism.
• Monitor for GI and bleeding risks; never combine with other NSAIDs.
• Alternative veterinary-approved NSAIDs are usually safer for routine use.

Curious about aspirin’s use in your pet’s care? Need a safe, personalized medication plan? Talk to Ask A Vet 24/7 through our app—expert veterinary advice is just a tap away. 🐾❤️