Treatment may not be necessary if the patient has unlimited access to water and PU/PD is not distressing to the owner.2
Desmopressin, a synthetic AVP analogue, can be given for partial or complete CDI; prognosis depends on the underlying cause of CDI. Desmopressin is a potent V2 receptor agonist and has minimal effects in V1 receptors if no hypertension is observed. The 0.01% human intranasal solution (dogs, 1-4 drops [≈1.5-5 μg/drop] q8-24h; cats, 1 drop q12h) should be administered in the conjunctival sac or nose. The injectable formulation of desmopressin (administered intravenously over 15-30 minutes and repeated as needed) in dogs and cats has a short-term effect and is best used in cases of diabetes insipidus as a diagnostic tool. Tablets can also be given (dogs, 100 μg PO q12-24h; cats, 25-50 μg PO q8-12h). Therapeutic response is variable.
Dose and frequency should be titrated to effect for each patient. Response to treatment is rapid, and PU returns quickly if treatment is discontinued.8 Desmopressin is generally safe, and complications are uncommon.1 The most common complications are hyponatremia and failure to decrease water intake. If the patient develops hyponatremia, desmopressin should be discontinued, then only given as needed. Close monitoring of electrolytes and USG is needed at the beginning of treatment until the appropriate individual dose is achieved.
In this patient, phenylpropanolamine (1 mg/kg PO q12h) was tried without success to manage the urinary incontinence episodes. The patient was then started on an initial trial therapy of desmopressin tablets (0.2 mg PO q12h). The tablet dosage was later increased (0.3 mg PO q12h), after which USG was concentrated at 1.022 and clinical signs resolved.
The patient did not return for a follow-up examination within the next year. At an eventual return visit, she had a USG of 1.003, but the owner chose not to resume treatment.