Introduction:
Acute postoperative pain is the pain present in surgical patients following the procedure1. Pre-emptive analgesia describes the attempt to control pain in the pre-incisional period. It aims to prevent central hyperexcitability, which tends to amplify in the postoperative period2. A recent review of systematic reviews concluded that evidence for the efficacy of various drugs and strategies for managing postoperative pain in children is still inconclusive3. Dipyrone, however, was not evaluated in this review.
Dipyrone is effective in postoperative pain in children. There are 8 clinical trials that have used it alone or in combination with other medications4-11. It is one of the most widely-used analgesics in the postoperative period in several European12-13, African14 and Latin American countries15. However, there is concern about its potential for associated anaphylaxis and agranulocytosis16. Its use is banned in more than 20 countries.
The real incidence of these adverse effects, however, is low. In a multicentre study involving more than 1,177 children treated with dipyrone in the postoperative period, the incidence of serious adverse effects was less than 0.3%, with no case of agranulocytosis17. Two studies, one involving several European countries (Germany, Italy and Spain)18 and another only in the city of Berlin19, estimated an incidence of agranulocytosis of 1.1 per million inhabitants/year and 0.96 cases per million inhabitants/year, respectively. In the city of Barcelona, ​​the estimate was 0.56 cases per million inhabitants/year20. The risk of severe complications and the availability of alternatives continue to contraindicate its use in the opinion of some21. Despite the ban in several countries, dipyrone is the most widely used painkiller in the postoperative period for children in Brazil, perhaps due to its low cost and the lack of an injectable form of paracetamol, at least until April 202022. In terms of oral analgesic medication, in contrast with the preference for paracetamol in different regions of the world23, in our country it is the most widely-used self-medication, as it is sold as an over-the-counter medicine24.
Dipyrone has been used for decades in children in the postoperative period of tonsillectomy. This surgery is the 2nd most common outpatient procedure in the USA25,26. Its main complication is pain that can lead to a reduction in oral intake, dehydration and weight loss27. The latest North-American Clinical Practice Guideline on Tonsillectomy contains 2 strong recommendations about analgesia: 1. to use analgesics in the post-operative period and 2. the contraindication in the use of opioids, especially in children under 1227. This latter recommendation is based on the FDA’s warning of the risk of respiratory depression and death using codeine28. In context of tonsillectomy, intravenous dipyrone could represent an alternative to opioids, where odynophagia with consequent difficulty in swallowing is almost universal.
The aim of this study was to review the analgesic use of dipyrone in the postoperative period of tonsillectomy in children.