NSAIDs similarly effective to acetaminophen plus codeine for post-laparotomy pain and may reduce adverse effects
- Cliff Richardson
School of Nursing, Midwifery and Social Work, University of Manchester, Jean McFarlane Building, Oxford Road, Manchester M13 9PL, UK;
This is a review of the literature on pain relief following abdominal surgery. There is some confusion over the focus of the review: despite the title, most of the discussion is about pain in the postpartum period, including pain following caesarean section and episiotomy; however, few of the reviewed papers in fact deal with postpartum pain. The review’s analgesic focus on the use of codeine-acetaminophen and non-steroidal antiinflammatory drugs (NSAIDs) adds to the growing body of literature comparing these two forms of pain relief.
The authors constructed search algorithms using terms appropriate for postpartum pain and for pain following general surgery; however, this is not necessarily commensurate with the full and short titles of the paper, which state post-abdominal surgery and post-laparotomy pain. Suitable databases, including Medline, Embase, CINAHL and the Cochrane Library, were searched. It is unclear from the text of the review how the search algorithms were combined to retrieve papers on hernia repair, varicose vein resection, laparoscopic cholecystectomy, haemorrhoidectomy and vasectomy. It is debatable whether it is sensible to compare pain following these other forms of surgery with pain following caesarean section and episiotomy, and the authors do not justify this comparison. As the choice of papers is not closely aligned with the postpartum experience, it is difficult to accept that the conclusions from the papers used in this review can be safely transferred to the field of postpartum pain management.
The search strategy found 212 potential articles. These were narrowed to 9 using inclusion and exclusion criteria that are not well described. The methods section mentioned that a screening process for relevance that assessed population, intervention, comparison and outcome was used to filter the 212 articles. However, the rigour of this process must be questioned: the inclusion of a randomised controlled trial of patients undergoing vasectomy does not meet the criteria for pain following childbirth or general abdominal surgery, although it may have been assumed to be relevant for comparison to episiotomy pain. A quick Medline search suggests that this comparison has not been made previously. All papers were screened for appropriate outcome measures. These were pain visual analogue scale score (although it is unclear which score was used—the highest/lowest value or a composite score over time—or, indeed, whether all the papers used the same value) and the number of adverse events (again it is not clear what these adverse events were, but the conclusions talk mainly about constipation). The nine papers finally chosen were assessed using the CONSORT statement and the Jadad score (range 1–5). Two of the papers were of low methodological quality and could have been rejected from the remainder of the review. Overall, the review would have benefited from a consistent approach: either the authors were reviewing the literature on postpartum pain management or they were reviewing the literature on pain following abdominal surgery (laparotomy). Attempting to move between these areas leaves the reader confused.
There is always tension about the use of these analgesics in practice. A large proportion of people do not have enough of the enzyme CYP2D6 to produce analgesia following administration of codeine.1 On the other hand, NSAIDs have contraindications; hence, practitioners and patients are often wary of even short-term use. This review does not add to the debate; indeed, the lack of focus may well create confusion for practitioners.
Overall, the results are in agreement with those of other studies and with current opinion in postsurgical practice that codeine-based analgesia is equivalent to that produced by NSAIDs. This should be tempered by the fact that codeine is ineffective in a proportion of the population; therefore, the suggestion is that NSAIDs are only as good as a relatively inefficacious analgesic or in this case that they are aligned only to the effects of acetaminophen. It may be that neither of these analgesics is sufficient following major surgery (laparotomy or caesarean section). They may, however, be sufficient for less major surgery (episiotomy). This paper does not help solve this conundrum.
To identify the best form of analgesia for postpartum pain, well-constructed randomised controlled trials and comparison studies of all potential analgesics currently in use in this area are required. It is unlikely that one review would be able to cover pain from abdominal surgery and pain from episiotomy; it may be sensible in future to treat these separately.
Competing interests None.