Abstract

Background

Renal colic pain is extremely painful and requires immediate treatment with strong analgesics. Dipyrone is the most popular non‐opioid first line analgesic in many countries but in others it has been banned (e.g. USA, UK) because of its association with blood dyscrasias such as agranulocytosis. Since dipyrone is used in many countries (e.g. Brazil, Spain) there is a need to determine the benefits and harms of its use to treat renal colic pain.

Objectives

Assess quantitatively the analgesic efficacy and adverse effects of single‐dose dipyrone in adults with moderate to severe renal colic pain.

Search methods

Published reports were identified from electronic databases (MEDLINE, EMBASE, The Cochrane Library, LILACS) and additional studies were identified from the reference lists of retrieved reports. Date of the most recent search: January 2000.

Selection criteria

Inclusion criteria were: full journal publication; RCT with a double‐blind design; adult patients with baseline renal colic pain of moderate or severe intensity; treatment arms which included dipyrone (oral, intramuscular or intravenous administration) and a control; single dose data.

Data collection and analysis

Summed pain intensity and pain relief data were extracted and converted into dichotomous information to yield the number of patients with at least 50% pain relief over 15‐30 minutes, 1‐2 hours and six hours. The proportion of patients with at least 50% pain relief was calculated. Single dose adverse effect data were collected.

Main results

Eleven studies with 1053 patients (550 on dipyrone) met the inclusion criteria. Unfortunately, few data were available for analysis; most analyses were based on the results of single, small trials and statistical pooling of the results was inappropriate. Efficacy estimates were calculated as the weighted mean percent of patients achieving at least 50% pain relief with the range of values from trials contributing to the analysis. However, these estimates were not robust. Commonly reported adverse effects with intravenous dipyrone were dry mouth and somnolence, and one study reported pain at the injection site. Insufficient information was available for safety analyses.

Authors' conclusions

Limited available data indicated that single dose dipyrone was of similar efficacy to other analgesics used in renal colic pain, although intramuscular dipyrone was less effective than diclofenac 75 mg. Combining dipyrone with antispasmolytic agents did not appear to improve its efficacy. Intravenous dipyrone was more effective than intramuscular dipyrone. Dry mouth and somnolence were commonly reported with intravenous dipyrone. None of the studies reported agranulocytosis.

Author(s)

Jayne Edwards, Fuensanta Meseguer, Clara Faura, R Andrew Moore, Henry J McQuay, Sheena Derry

Abstract

Plain language summary

Single dose dipyrone for acute renal colic pain

Renal colic pain is extremely painful and requires immediate treatment with strong analgesics. Dipyrone is a non‐opioid analgesic widely used for this purpose but not licensed in some countries (e.g., USA, UK) because of potentially fatal side effects (agranulocytosis). This review aimed to assess the effectiveness and safety of single dose dipyrone in adults with moderate/severe renal colic pain but there were too few data to obtain clear results. The data available indicated that intravenous dipyrone was more effective than intramuscular dipyrone, and combining dipyrone with antispasmolytic agents did not improve its efficacy. Commonly reported side effects included dry mouth and drowsiness, and some patients experienced pain at the injection site. Agranulocytosis was not reported.

Author(s)

Jayne Edwards, Fuensanta Meseguer, Clara Faura, R Andrew Moore, Henry J McQuay, Sheena Derry

Reviewer's Conclusions

Authors' conclusions 

Implications for practice 

The results obtained in this analysis were not robust, because few patients were included in the analyses for the different doses of dipyrone and the different routes of administration. Intravenous dipyrone appears to be an effective analgesic for treating renal colic pain.

Pain at the injection site occurred frequently in studies which assessed multiple doses of dipyrone, and was also reported in one single dose study.

There was insufficient information of adequate quality for any safety analyses to be conducted. Dipyrone is known to cause blood dyscrasias such as agranulocytosis (an adverse effect which can occur with short‐term treatment) but there was no mention of blood dyscrasias in these trials. There is a wealth of literature on agranulocytosis: the most recent, large, international study found vastly differing rates of agranulocytosis in the 11 countries where information was collected (IAAA Study 1986). There are a number of published criticisms of this study (Kramer 1988). None of these criticisms mentions the importance of size (of the population studied and the analyses) for detecting true incidence rates for rare events. Size is an important issue of study validity (Moore 1998). Recent reports from Sweden have suggested a rate of one case of agranulocytosis in 1700 prescriptions. This rate was based on six cases in 10,000 prescriptions. Information is available on the Swedish website (http://www.mpa.se/biverkningar/biv99/novalgin.html). In the absence of other robust information, the Swedish data is probably the most reliable on which to base decisions.

Implications for research 

The risk of agranulocytosis needs to be quantified using adequately powered studies of good methodological design. Methodologically rigorous studies would be required to establish the benefit/risk trade‐off for dipyrone, particularly if the risk of rare adverse events was to be established. Such studies would need to be large, of adequate duration, provide clear definitions of outcomes and independent verification of cases, and provide information on exposure to treatment.

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