Results:
The maximum number of 1151 articles were selected using the descriptors
“dipyrone or metamizol and postoperative pain”. The number of articles
found in EMBASE was 1,151, in PUBMED 336 and in VHL 345. When the
descriptor “children” was introduced to the previous search, the
corresponding numbers were 120, 49 and 42. When adding “randomised
clinical trial”, the corresponding numbers were 31, 13 and 19. It was
decided not to use the last search and the abstract, and the materials
and methods of each article obtained from the search with the
descriptors “dipyrone or metamizole and postoperative pain and
children” were manually reviewed. Nine randomised clinical trials were
identified evaluating the postoperative analgesic effect of dipyrone in
isolation or associated with one of the groups. When only studies
dealing with tonsillectomy were selected, 3 remained and it was seen
that there was a duplicate of one. The final search result was 2
randomised clinical trials that evaluated the effect of dipyrone against
placebo, one in pre-emptive and the other in the postoperative
analgesia, in children undergoing tonsillectomy, with or without
adenoidectomy or placement of ventilation tubes.
Tables 1, 2 and 3 show information on the 2 articles included. Table 1
shows the study identification, investigational model, follow-up time,
inclusion criteria, age, sex and the sample size.
(Table 1: Characteristics of selected articles.)
The studies had short follow-up times (maximum 24 hours). While the
first study involved only older children, the second study included
children from 3 years old. While in the first study, only cases of
isolated tonsillectomy were evaluated, in study 2, tonsillectomy either
with or without associated adenoidectomy and / or placement of
ventilation tubes was allowed.
Table 2 shows the description of the data referring to the intervention
groups (random number and number who completed the study in each group),
type of analgesia and form of administration of dipyrone. Both studies
had a 100% completion rate for the randomised sample. While in the
first study analgesia was post-operative, in the 2nd it was applied
pre-emptively, thus, making it difficult to directly compare the two
studies. The first study brought an innovation to the paediatric surgery
postoperative period, in the use of PCA (patient-controlled analgesia).
(Table 2: Description of the intervention groups, type of
analgesia and form of administration of dipyrone.)
Table 3 describes the strengths and weaknesses of each study, the
primary and secondary outcomes, the results, the level of evidence
according to Oxford criteria, the levels of evidence and degrees of
recommendation according to the GRADE classification and the Jadad
scores.
(Table 3: Strengths and weaknesses, primary and secondary
outcomes, main results and Oxford, GRADE and Jadad classifications of
studies.)
It is evident that both studies demonstrated care in their
methodological approach. For this reason, the Jadad classification for
the first paper was excellent (score = 5) and the second was classed as
good (score = 4). The study by Kocum et al. lost a point for not
explicitly describing withdrawals and losses. The other classifications
were equal for both studies. Regarding the analgesic results measured by
validated pain scales in childhood, dipyrone and paracetamol were
superior to placebo and similar to each other in many measured
intervals. The same was observed for the use of rescue pethidine, and
this did not differ between active comparison groups.