Naproxen toxicity in pets

Naproxen is a nonsteroidal anti-inflammatory drug (NSAID) that inhibits COX enzymes, reducing prostaglandin production to lower inflammation. However, it also blocks protective prostaglandins, especially in non-selective NSAIDs. Clearance and half-life vary by species; for instance, naproxen sodium is rapidly absorbed (68–100% bioavailability) and has a long half-life in dogs (about 74 hours).

Gastrointestinal: abdominal pain, anorexia, vomiting (with od without blood), diarrhea, melena, GI ulcers or perforation may occur.

Renal: uremic breath, polyuria, polydipsia, acute renal failure - oliguria or anuria.

Neurological: ataxia, seizures, obtundation, coma.

General: schock due to hemmorhage or GI perforation, anemia, thrombocytopathia.

• Induce emesis within 30 minutes of ingestion for best results, as ibuprofen is absorbed quickly.

• If large amounts were ingested, emesis within 3–6 hours may still be effective due to delayed gastric emptying.

• Avoid emesis if CNS signs are present to prevent aspiration; perform gastric lavage instead.

• Administer activated charcoal (2–4 g/kg) without a cathartic, repeating 1 g/kg every 4–6 hours for 24–48 hours due to enterohepatic recirculation.

• Provide IV fluids at maintenance or 1.5 times maintenance to enhance renal elimination.

• Intubation and mechanical ventilation may be necessary for acute CNS signs or respiratory depression.

• Monitor urine output in animals exposed to nephrotoxic NSAID doses.

• If volume depleted and oliguric, give IV fluid boluses (10 mL/kg over 30 minutes) to expand intravascular volume.

• If volume expanded and oliguric, administer furosemide (1–2 mg/kg IV) or mannitol (1 g/kg IV over 15 minutes) to stimulate urine production.

• Symptomatic treatment: antiemetics, gastroprotecrion (misoprostol - 2-5 ug/kg 2-3 times a day, PPI, sucralfate), anticonvulsants (diazepam, midazolam) blood transfusion (if severe GI hemmorhage occurs)

• Intralipid Therapy:

For severe cases with neurological signs, administer a bolus of 1.5–4 mL/kg IV of 20% intralipid emulsion over 1 minute, followed by a constant rate infusion (CRI) of 0.25 mL/kg/minute over 30–60 minutes.

Early intervention is key to reducing the severity of naproxen toxicity. Immediate veterinary care is needed