MorphineDose, contraindications and adverse effects for Cats, Dogs, Horses and Sheep.

Full mu-opioid receptor agonist; the prototype analgesic against which other opioids are compared. Morphine is used to treat acute pain in dogs, cats, horses, swine, sheep, and goats. Morphine is used as a preanesthetic in several species.

The morphine-like agonists (eg, morphine, meperidine, hydromorphone) have primary activity at mu-opioid receptors, with some activity at delta- and kappa-opioid receptors.

Morphine is contraindicated in patients that are hypersensitive to narcotic analgesics, are receiving or are within 14 days of receiving monoamine oxidase inhibitors (MAOIs), have diarrhea caused by a toxic ingestion until the toxin is eliminated from the GI tract, or have GI tract obstruction or paralytic ileus. Avoid morphine in envenomation situations, as clinical signs associated with histamine release can be confused with anaphylaxis.

At recommended dosages, opioids have limited respiratory depressant effects in veterinary species compared to humans. Decreased tidal volume, depressed cough reflex, and drying of respiratory secretions may have a detrimental effect on susceptible patients (eg, patients with brachycephalic airway syndrome, aspiration, or pneumonia). Bronchoconstriction following IV morphine doses may be noted in dogs20; significant hypotension results if morphine is administered rapidly IV.

■ Respiratory rate and depth; ETCO2; pulse oximetry (SpO2) ■ Heart rate ■ CNS level of depression/excitation ■ Blood pressure (especially with IV use) ■ Analgesic efficacy ■ Body temperature