Paracetamol (Acetaminophen)
N-acetyl-p-aminophenol
Also known as: Pardale-V · Perfalgan · Panadol · Tylenol · Acetaminophen · APAP · N-acetyl-p-aminophenol
Reviewed by the VetSheet Veterinary TeamUpdated Apr 5, 2026Evidence-based veterinary reference
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Dosing by species
🌎 NA — North America🌍 EU — Europe
Dogs
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| Mild to moderate pain / Antipyretic | 10-20 mg/kg | PO/IV | q8h | 5-7 days (for acute pain) | 🌍 EU |
| Mild to moderate pain (Pardale-V preparation) | 1 tablet per 12 kg body weight (equivalent to 33 mg/kg) | PO | q8h | Max 7 days before titrating down | 🌍 EU |
- Mild to moderate pain / Antipyretic: For acute pain management, doses at the top of the range (20 mg/kg) can be used for up to 5-7 days.
- Mild to moderate pain (Pardale-V preparation): Authorized dose for Pardale-V. After 7 days, titrate down to the lowest effective dose. Codeine component is not bioavailable.
Cats
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| All indications | Do not use | PO/IV | N/A | N/A | 🌍 EU |
- All indications: Absolute contraindication. Fatal toxicosis due to methaemoglobinaemia.
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Overview
Paracetamol is a centrally acting analgesic and antipyretic medication used for the control of mild to moderate pain and fever. It has poor anti-inflammatory effects compared to traditional NSAIDs but is believed to produce fewer gastrointestinal side effects, making it a useful alternative for patients with gastric ulceration. Injectable paracetamol is also utilized as an adjunctive perioperative analgesic in dogs.
CRITICAL WARNING: Paracetamol is highly toxic and strictly contraindicated in cats due to their inability to safely metabolize the drug.
Clinical Pearl: The licensed veterinary oral preparation (Pardale-V) contains codeine; however, due to a high first-pass metabolism of opioids in dogs, the codeine component is not bioavailable and does not significantly contribute to analgesia.
Mechanism of action
The exact mechanism of action remains partially unclear. It is proposed that its antipyretic and analgesic actions are due to:
- Decreased prostaglandin synthesis specifically within the central nervous system (CNS).
- Possible indirect actions on the cannabinoid system. Unlike traditional NSAIDs, it has minimal peripheral cyclooxygenase (COX) inhibition, which explains its lack of significant anti-inflammatory activity and reduced gastrointestinal toxicity.
Safety & warnings
Contraindications
- Cats (absolute contraindication due to fatal toxicosis)
- Patients with pre-existing severe hepatic impairment
Adverse effects
- Hepatotoxicity (dose-dependent)
- Methaemoglobinaemia (especially in cats)
- Facial edema
- Cyanosis
Precautions
Feline Toxicity: Do not use in cats. They lack the glucuronyl transferase enzymes required to metabolize the drug, leading to fatal methaemoglobinaemia and hepatotoxicity even at very low doses.
- Use with caution in dogs with pre-existing liver disease.
- The combination of an NSAID and paracetamol for perioperative analgesia is common in human medicine but has not undergone rigorous safety or efficacy investigation in dogs.
Drug interactions
Enhances the absorption of paracetamol, thereby enhancing its clinical and potentially toxic effects.
May increase the production of toxic metabolites (NAPQI), enhancing the risk of hepatotoxicity.
Monitoring
- Liver enzyme panel (ALT, AST, ALP, Bilirubin) if prolonged use or overdose is suspected
- Clinical signs of toxicity (jaundice, vomiting, lethargy)
- Mucous membrane color (monitoring for cyanosis/brown blood indicative of methaemoglobinaemia)
Pharmacokinetics
Half-life
Absorption
Rapidly and well absorbed from the gastrointestinal tract. Absorption is enhanced by metoclopramide.
Distribution
Widely distributed throughout most body tissues and fluids.
Metabolism
Undergoes extensive hepatic metabolism. A minor pathway utilizes cytochrome P450 to form the toxic intermediate N-acetyl-p-aminobenzoquinonimine (NAPQI). Cats are deficient in glucuronyl transferase, forcing metabolism down the toxic NAPQI pathway.
Elimination
Metabolites are primarily excreted in the urine.
Overdose
Overdose of paracetamol causes severe liver damage. Metabolism produces the toxic intermediate N-acetyl-p-aminobenzoquinonimine (NAPQI), which depletes hepatic glutathione, leading to hepatocyte cell death and centrilobular hepatic necrosis. In cats, it causes fatal methaemoglobinaemia.
Treatment:
- Decontamination (emesis/activated charcoal) if ingestion is recent.
- Antidote: Oral methionine or IV acetylcysteine (N-acetylcysteine). These are directed at replenishing hepatic glutathione stores to neutralize NAPQI, though clinical data in veterinary species is limited.
- Supportive care (IV fluids, oxygen therapy, blood transfusions if severe methaemoglobinaemia occurs).
Available products
Formulations
- 500 mg tablet
- 120 mg/5 ml oral suspension
- 250 mg/5 ml oral suspension
- 400 mg paracetamol / 9 mg codeine phosphate tablet (Pardale-V)
- 10 mg/ml injectable solution
Veterinary
- Pardale-V (400 mg paracetamol / 9 mg codeine phosphate tablet)
Human-labeled
- Paracetamol 500 mg tablets
- Paracetamol 120 mg/5 ml oral suspension
- Paracetamol 250 mg/5 ml oral suspension
- Perfalgan 10 mg/ml injectable solution
Regulatory status
Pardale-V is authorized for dogs.
Pardale-V is POM-V. Human preparations may be P or POM.
No regulatory data for: 🇺🇸 US · 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU
Storage & stability
Store at room temperature (15-30°C), protected from light and moisture. Keep liquid suspensions tightly closed.
Client information
Paracetamol is a medication used to relieve mild to moderate pain and reduce fever in dogs. It is sometimes used when other pain medications (like NSAIDs) upset your dog's stomach.
CRITICAL WARNING: NEVER give this medication to cats. Even a tiny amount is highly toxic and often fatal to cats because they lack the liver enzymes needed to process it.
- Always give the exact dose prescribed by your veterinarian. Do not use human paracetamol products without explicit veterinary instruction, as dosing is very different for dogs.
- Contact your vet immediately if your dog shows signs of vomiting, lethargy, yellowing of the gums/eyes, or difficulty breathing.
VetSheet drug reference is intended for licensed veterinary professionals as a clinical decision-support aid, not a substitute for professional judgement or the manufacturer’s current label.