Postoperative analgesia and side effects of oral or injectable metamizole (dipyrone) in dogs and cats

PICO Question In dogs and cats after surgery, does the peri-operative administration of injectable or oral metamizole (dipyrone) as opposed to no intervention result in lower postoperative pain scores or higher incidence of side effects?   Clinical bottom line Category of research Treatment. Number and type of study designs reviewed Three prospective, randomised, blinded, clinical studies were critically reviewed. Strength of evidence Weak. Outcomes reported Variables assessed included: different pain assessment methods, metamizole dose required to reduce peri- and postoperative pain scores, changes in cardiovascular variables (heart rate, systolic, mean and diastolic blood pressure), changes in respiratory variables and variations in haematological and biochemical variables. Conclusion In healthy cats and dogs undergoing ovariohysterectomy, the use of metamizole in the peri- and postoperative period was associated with some reduction in pain levels (i.e., lower pain score or reduced need for rescue analgesia). In dogs, metamizole alone provided insufficient analgesia. No study evaluating metamizole after orthopaedic surgery was found. No evidence suggested that using metamizole peri-operatively resulted in higher incidence of side effects.   How to apply this evidence in practice The application of evidence into practice should take into account multiple factors, not limited to: individual clinical expertise, patient’s circumstances and owners’ values, country, location or clinic where you work, the individual case in front of you, the availability of therapies and resources. Knowledge Summaries are a resource to help reinforce or inform decision making. They do not override the responsibility or judgement of the practitioner to do what is best for the animal in their care.