Oral morphine used to control intensive pain in a dog (canis familiaris) with tonsil carcinoma, and metastasis in medial retropharyngeal lymph node

Abstract An 11‐year‐old, female West Highland white terrier presenting cough, emesis, diarrhoea and hyporexia refractory to symptomatic treatment was subjected to endoscopy showing increased palatine tonsil region. Biopsy findings revealed a carcinoma. Computed tomography also showed an increased right medial retropharyngeal lymph node dorsally related to the right wing of the atlas causing a periosteal reaction, and complete fracture of the right stylohyoid bone. After 20 days of diagnosis, severe cervical pain started presenting as some vocalisation before being touched, accompanied by a soft touch in the cervical region and cervical stiffness. The initial analgesic protocol was tramadol, metamizole, methadone, gabapentin, and constant rate infusion with esketamine and lidocaine. However, signs of pain remained. A specialist in pain management was called and after the inclusion of dexamethasone (0.2 mg/kg subcutaneously), 0.4 mg/kg subcutaneous morphine every 4 hours, which was changed to 1 mg/kg morphine administered orally every 4 hours, the pain was effectively controlled.