Papaveretum
Mixture of opium alkaloids
Also known as: Omnopon · Opium alkaloids
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 |
|---|---|---|---|---|---|
| Analgesia / Sedation | 0.2-0.8 mg/kg | IV/IM/SC | PRN | Duration of action is approximately 4 hours | 🌍 EU |
- Analgesia / Sedation: Use lower doses IV; only use higher doses when deep sedation is required. Often given as part of a combination for sedation.
Cats
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| Analgesia / Sedation | 0.2-0.3 mg/kg | IV/IM/SC | PRN | Duration of action is approximately 4 hours | 🌍 EU |
- Analgesia / Sedation: Often given as part of a combination for sedation.
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Overview
Papaveretum is a mixture of the alkaloids of opium containing the equivalent of anhydrous morphine 85.5%, anhydrous codeine 6.8% and papaverine 7.8%. It is used for the management of moderate to severe pain in the perioperative period and incorporated into sedative and pre-anaesthetic medication protocols to provide improved sedation and analgesia. It has a similar effect to morphine with an approximate 4-hour duration of action.
Clinical Warning: Methadone should be used in preference to papaveretum as the licensed alternative for single or repeated bolus administration to dogs and cats. Papaveretum is not widely used for postoperative analgesia but tends to be used in combination with acepromazine to provide good sedation in aggressive dogs.
Mechanism of action
Papaveretum provides analgesia primarily mediated by acting as an agonist at the mu (μ) opioid receptor in the central nervous system. This binding inhibits the release of nociceptive neurotransmitters (such as Substance P) → altering the perception of and response to pain.
Safety & warnings
Contraindications
- No specific contraindications available, but use with caution in patients with impaired liver function or pregnant animals near parturition.
Adverse effects
- Vomiting (common)
- Respiratory depression (especially IV during general anaesthesia)
- Constriction of gastrointestinal sphincters (e.g., pyloric sphincter)
- Reduction in gastrointestinal motility
- Sedation in neonates (crosses placenta)
Precautions
Normal safety and handling precautions should be observed.
Respiratory Monitoring: Respiratory depression may occur when given IV during general anaesthesia due to increased anaesthetic depth. Respiratory function must be monitored in anaesthetized patients.
Variable Response: The response to all opioids is highly variable between individual patients; imperative to assess pain after administration.
Hepatic Impairment: Metabolized in the liver; prolonged effects may be seen in patients with impaired liver function.
Pregnancy: Crosses the placenta and may exert sedative effects in neonates born to bitches treated prior to parturition.
Drug interactions
Increased CNS or respiratory depression
Increased CNS or respiratory depression
Increased CNS or respiratory depression
Increased CNS or respiratory depression; often used together intentionally for deep sedation
Increased CNS or respiratory depression
Monitoring
- Respiratory rate and depth (especially under general anaesthesia)
- Pain scores (due to variable individual response)
- Level of sedation
- Heart rate and blood pressure
Pharmacokinetics
Half-life
Absorption
Well absorbed following IM or SC administration.
Distribution
Crosses the placenta and can affect neonates.
Metabolism
Metabolized in the liver.
Elimination
Excreted primarily via the kidneys as metabolites.
Overdose
Overdose can lead to severe respiratory depression, profound sedation, and potentially cardiovascular collapse. Severe adverse effects can be treated and reversed with the opioid antagonist naloxone.
Available products
Formulations
- Injectable solution: 7.7 mg/ml (equivalent to 5 mg anhydrous morphine/ml)
- Injectable solution: 15.4 mg/ml (equivalent to 10 mg anhydrous morphine/ml)
- Injectable solution: 15.4 mg/ml papaveretum and 0.4 mg/ml hyoscine (scopolamine)
Veterinary
- Omnopon Injectable solution
- Papaveretum Injectable solution
Regulatory status
POM CD SCHEDULE 2
POM CD SCHEDULE 2
No regulatory data for: 🇺🇸 US · 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU
Storage & stability
Store according to local regulations for Schedule 2 Controlled Drugs. Keep in a locked receptacle. Protect from light.
Client information
Papaveretum is a strong, controlled painkiller used in the veterinary clinic, usually given by injection before or during surgery.
- It is very effective at stopping pain but can cause your pet to feel nauseous or vomit.
- It may cause your pet to be quite sleepy.
- If your pet is discharged shortly after receiving this medication, keep them in a quiet, comfortable place and monitor their breathing. Contact your vet if they seem excessively drowsy or have 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.