1) Effectiveness of miscellaneous analgesics with emphasis on
dipyrone in the post-operative period of tonsillectomy in children:
Dipyrone has an efficacy, measured by the number of patients needed to
treat to achieve a 50% reduction in postoperative pain in 4 to 6 hours,
that is lower than potassium diclofenac and etoricoxib, but greater than
several NSAIDs (paracetamol, naproxen, ibuprofen, celecoxib, aspirin and
sodium diclofenac). Unfortunately, all these estimates are for adults,
and there are no similar studies in children34. There
is one systematic review specifically evaluating the efficacy of
dipyrone in postoperative pain in children35. Ten
systematic reviews were identified regarding postoperative analgesia in
tonsillectomy performed in children. The first studied the use of
systemic paracetamol, NSAIDs and opioids. However, it did not comment on
dipyrone36. Two analysed the effect of ketamine via
peritonsillar or systemic injection37,38, two studied
the effect of corticosteroids39,40, one focused on the
effect of bupivacaine41 and the other on
dexmedetomidine compared to morphine or fentanyl42. A
Cochrane systematic review analysed the form of analgesic prescription
(different analgesics, but never dipyrone), if required or
fixed43. Finally, there was another review that was
restricted to the use of oral rinses and sprays to improve recovery
followed by tonsillectomy44. An overview of all these
systematic reviews was given in the recent work by Boric et al.,
20173.
As demonstrated in the present review, there are only two randomised
clinical trials that have evaluated the analgesic effect of dipyrone in
the postoperative period of tonsillectomy in
children6,7. Unfortunately, it was not possible to
perform a meta-analysis, as one study included isolated
tonsillectomy7 and the other allowed associated
adenoidectomy and / or ventilation tubes6, which can
lead to different levels of pain, due to the greater manipulation of the
patients. In addition, one study evaluated preemptive6and the other postoperative analgesia7. Finally, the
study of pre-emptive analgesia gave a single dose of dipyrone or placebo
right after introduction of the anaesthetic6, while
the other study evaluated analgesia initiated in the postoperative
period through the use of PCA7. The limitation is that
PCA is not available in most hospitals and requires the understanding
and collaboration of the patient, thus being ineffective for young
children.
Both studies demonstrated adequate methodological care, with sample size
calculations, and with randomisation performed through the website
randomization.com. Moreover, hypotheses were established a priori, with
the use of a placebo with the same characteristics as the active
medication, with adequate blinding of both patients and examiners, and
with effective and validated outcome measures, in addition to a careful
choice of the statistical tests used. Together with another study
dealing with abdominal surgery5, they comprise the 3
clinical trials with the best level of evidence of all studies commented
here, according to the Oxford classification, the GRADE system or the
Jadad scores.
However, the studies have short follow-up times (maximum 24 hours). It
would be preferable to have a longer follow-up time to monitor the
effect of dipyrone, as the pain after tonsillectomy persists for at
least 7 days. Another limitation of the results is that, in addition to
being developed by the same group of researchers and not being able to
be combined for a meta-analysis for the reasons already specified, the
data have never been replicated elsewhere by different researchers,
which can limit the extrapolation of data to populations other than
Turkish patients.