Onset and duration of analgesia of diclofenac potassium in the treatment of postepisiotomy pain

Oral non-steroidal anti-inflammatory drugs (single dose) for perineal pain in the early postpartum period

BACKGROUND

Many women experience perineal pain after childbirth, especially after having sustained perineal trauma. Perineal pain-management strategies are an important part of postnatal care. Non-steroidal anti-inflammatory drugs (NSAIDs) are a commonly-used type of medication in the management of postpartum pain, and their effectiveness and safety should be assessed. This is an update of a review first published in 2016.

OBJECTIVES

To determine the effectiveness of a single dose of an oral NSAID for relief of acute perineal pain in the early postpartum period.

SEARCH METHODS

For this update, we searched the Cochrane Pregnancy and Childbirth Group's Trials Register, ClinicalTrials.gov, the WHO International Clinical Trials Registry Platform (ICTRP) (9 December 2019), OpenSIGLE and ProQuest Dissertations and Theses (28 February 2020), and reference lists of retrieved studies.

SELECTION CRITERIA

Randomised controlled trials (RCTs) assessing a single dose of a NSAID versus a single dose of placebo, paracetamol or another NSAID for women with perineal pain in the early postpartum period. We excluded quasi-RCTs and cross-over trials. We included papers in abstract format only if they had sufficient information to determine that they met the review's prespecified inclusion criteria.

DATA COLLECTION AND ANALYSIS

Two review authors (FW and VS) independently assessed all identified papers for inclusion and risks of bias, resolving any discrepancies through discussion. Two review authors independently conducted data extraction, including calculations of pain relief scores, and checked it for accuracy. We assessed the certainty of the evidence using the GRADE approach.

MAIN RESULTS

We included 35 studies examining 16 different NSAIDs and involving 5136 women (none were breastfeeding). Studies were published between 1967 and 2013. Risk of bias due to random sequence generation, allocation concealment and blinding of outcome assessors was generally unclearly to poorly reported, but participants and caregivers were blinded, and outcome data were generally complete. We downgraded the certainty of evidence due to risk of bias, suspected publication bias, and imprecision for small numbers of participants. NSAID versus placebo Compared to women who receive a placebo, more women who receive a single-dose NSAID may achieve adequate pain relief at four hours (risk ratio (RR) 1.91, 95% confidence interval (CI) 1.64 to 2.23; 10 studies, 1573 women; low-certainty evidence) and at six hours (RR 1.92, 95% CI 1.69 to 2.17; 17 studies, 2079 women; very low-certainty evidence), although we are less certain about the effects at six hours. At four hours after administration, women who receive a NSAID are probably less likely to need additional analgesia compared to women who receive placebo (RR 0.39, 95% CI 0.26 to 0.58; 4 studies, 486 women; moderate-certainty evidence) and may be less likely to need additional analgesia at six hours after initial administration, although the evidence was less certain at six hours (RR 0.32, 95% CI 0.26 to 0.40; 10 studies, 1012 women; very low-certainty evidence). One study reported that no adverse events were observed at four hours post-administration (90 women). There may be little or no difference in maternal adverse effects between NSAIDs and placebo at six hours post-administration (RR 1.38, 95% CI 0.71 to 2.70; 13 studies, 1388 women; low-certainty evidence). Fourteen maternal adverse effects were reported in the NSAID group (drowsiness (5), abdominal discomfort (2), weakness (1), dizziness (2), headache (2), moderate epigastralgia (1), not specified (1)) and eight in the placebo group (drowsiness (2), light-headedness (1), nausea (1), backache (1), dizziness (1), epigastric pain (1), not specified (1)), although not all studies assessed adverse effects. Neonatal adverse effects were not assessed in any of the studies. NSAID versus paracetamol NSAIDs may lead to more women achieving adequate pain relief at four hours, compared with paracetamol (RR 1.54, 95% CI 1.07 to 2.22; 3 studies, 342 women; low-certainty evidence). We are uncertain if there is any difference in adequate pain relief between NSAIDs and paracetamol at six hours post-administration (RR 1.82, 95% CI 0.61 to 5.47; 2 studies, 99 women; very low-certainty evidence) or in the need for additional analgesia at four hours (RR 0.55, 95% CI 0.27 to 1.13; 1 study, 73 women; very low-certainty evidence). NSAIDs may reduce the risk of requiring additional analgesia at six hours compared with paracetamol (RR 0.28, 95% CI 0.12 to 0.67; 1 study, 59 women; low-certainty evidence). One study reported that no maternal adverse effects were observed at four hours post-administration (210 women). Six hours post-administration, we are uncertain if there is any difference between groups in the number of maternal adverse effects (RR 0.74, 95% CI 0.27 to 2.08; 3 studies, 300 women; very low-certainty evidence), with one case of pruritis in the NSAID group and one case of sleepiness in the paracetamol group. Neonatal adverse effects were not assessed in any of the included studies. Comparisons of different NSAIDs or doses did not demonstrate any differences in effectiveness for any primary outcome measures; however, few data were available on some NSAIDs. None of the included studies reported on any of this review's secondary outcomes.

AUTHORS' CONCLUSIONS

In women who are not breastfeeding and who sustained perineal trauma, NSAIDs (compared to placebo or paracetamol) may provide greater pain relief for acute postpartum perineal pain and fewer women need additional analgesia, but uncertainty remains, as the evidence is rated as low- or very low-certainty. The risk of bias was unclear for many studies, adverse effects were often not assessed and breastfeeding women were not included. While this review provides some indication of the likely effect, there is uncertainty in our conclusions. The main reasons for downgrading were the inclusion of studies at high risk of bias and inconsistency in the findings of individual studies. Future studies could examine NSAIDs' adverse effects, including neonatal effects and the compatibility of NSAIDs with breastfeeding, and could assess other secondary outcomes. Future research could consider women with and without perineal trauma, including perineal tears. High-quality studies could be conducted to further assess the efficacy of NSAIDs versus paracetamol and the efficacy of multimodal treatments.

Paracetamol/acetaminophen (single administration) for perineal pain in the early postpartum period

BACKGROUND

Perineal pain is a common but poorly studied adverse outcome following childbirth. Pain may result from perineal trauma due to bruising, spontaneous tears, surgical incisions (episiotomies), or in association with operative vaginal births (ventouse or forceps-assisted births). This is an update of a review last published in 2013.

OBJECTIVES

To determine the efficacy of a single administration of paracetamol (acetaminophen) used in the relief of acute postpartum perineal pain.

SEARCH METHODS

For this update, we searched the Cochrane Pregnancy and Childbirth's Trials Register, ClinicalTrials.gov, the WHO International Clinical Trials Registry Platform (9 December 2019), and reference lists of retrieved studies.

SELECTION CRITERIA

Randomised controlled trials (RCTs), including cluster-RCTs, comparing paracetamol to placebo. We excluded quasi-RCTs and cross-over trials. Data from abstracts would be included only if authors had confirmed in writing that the data to be included in the review had come from the final analysis and would not change.

DATA COLLECTION AND ANALYSIS

Two review authors assessed each study for inclusion and extracted data. One review author reviewed the decisions and confirmed calculations for pain relief scores. We assessed the certainty of the evidence using the GRADE approach.

MAIN RESULTS

This update identified no new trials so the results remain unchanged. However, by applying the GRADE assessment of the evidence, the interpretation of main results differed from previous version of this review. We identified 10 studies involving 2044 women, but all these studies involved either three or four groups, looking at differing drugs or doses. We have only included the 1301 women who were in the paracetamol versus placebo arms of the studies. Of these, five studies (482 women) assessed 500 mg to 650 mg and six studies (797 women) assessed 1000 mg of paracetamol. One study assessed 650 mg and 1000 mg compared with placebo and contributed to both comparisons. We used a random-effects meta-analysis because of the clinical variability among studies. Studies were from the 1970s to the early 1990s, and there was insufficient information to assess the risk of bias adequately, hence the findings need to be interpreted within this context. The certainty of the evidence for the two primary outcomes on which data were available was assessed as low, downgraded for overall unclear risk of bias and for heterogeneity (I² statistic 60% or greater). More women may experience pain relief with paracetamol compared with placebo (average risk ratio (RR) 2.14, 95% confidence interval (CI) 1.59 to 2.89; 10 trials, 1279 women), and fewer women may need additional pain relief with paracetamol compared with placebo (average RR 0.34, 95% CI 0.21 to 0.55; 8 trials, 1132 women). However, the certainty of the evidence was low, downgraded for unclear overall risk of bias and substantial heterogeneity. One study used the higher dose of paracetamol (1000 mg) and reported maternal drug adverse effects. There may be little or no difference in the incidence of nausea (average RR 0.18, 95% CI 0.01 to 3.66; 1 trial, 232 women; low-certainty evidence), or sleepiness (average RR 0.89, 95% CI 0.18 to 4.30; 1 trial, 232 women; low-certainty evidence). No other maternal adverse events were reported. None of the studies assessed neonatal drug adverse effects.

AUTHORS' CONCLUSIONS

A single dose of paracetamol may improve perineal pain relief following vaginal birth, and may reduce the need for additional pain relief. Potential adverse effects for both women and neonates were not appropriately assessed. Any further trials should also address the gaps in evidence concerning maternal outcomes such as satisfaction with postnatal care, maternal functioning/well-being (emotional attachment, self-efficacy, competence, autonomy, confidence, self-care, coping skills) and neonatal drug adverse effects.

Composing Novel Diclofenac Potassium and l-Proline Salt Cocrystal as a Strategy to Increase Solubility and Dissolution

This research dealt with the multicomponent crystal developed from diclofenac potassium and l-proline to improve the pharmaceutical performance of this anti-inflammatory drug. Slow evaporation of the component mixture at a 1:1 M ratio, supported by ultrasonication, yielded a new salt cocrystal, which was characterized using thermal analysis, Karl Fischer titration, infrared spectrophotometry, powder diffractometry, and single crystal diffractometry. This salt cocrystal was confirmed as a tetrahydrate that comprised diclofenac potassium, l-proline, and water (1:1:4), named DKPH. The new salt cocrystal enhanced the solubility of diclofenac potassium by up to 3.56 folds and accelerated the intrinsic dissolution rate of 3.36 folds. It was supported by the solid and solution phase intermolecular interaction study. A different phase, which indicated a monohydrate form of the salt cocrystal, was found from the low humidity chamber during the isotherm sorption study. However, the tetrahydrate, DKPH, was proven as a stable form under ambient conditions.

Aspirin (single dose) for perineal pain in the early postpartum period

BACKGROUND

Perineal trauma, due to spontaneous tears, surgical incision (episiotomy), or in association with operative vaginal birth, is common after vaginal birth, and is often associated with postpartum perineal pain. Birth over an intact perineum may also lead to perineal pain. There are adverse health consequences associated with perineal pain for the women and their babies in the short- and long-term, and the pain may interfere with newborn care and the establishment of breastfeeding. Aspirin has been used in the management of postpartum perineal pain, and its effectiveness and safety should be assessed. This is an update of the review, last published in 2017.

OBJECTIVES

To determine the effects of a single dose of aspirin (acetylsalicylic acid), including at different doses, in the relief of acute postpartum perineal pain.

SEARCH METHODS

For this update, we searched the Cochrane Pregnancy and Childbirth's Trials Register (4 October 2019), ClinicalTrials.gov, the WHO International Clinical Trials Registry Platform (ICTRP) (4 October 2019) and screened reference lists of retrieved studies.

SELECTION CRITERIA

Randomised controlled trials (RCTs), assessing single dose aspirin compared with placebo, no treatment, a different dose of aspirin, or single dose paracetamol or acetaminophen, for women with perineal pain in the early postpartum period. We planned to include cluster-RCTs, but none were identified. We excluded quasi-RCTs and cross-over studies.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed study eligibility, extracted data and assessed the risk of bias of the included RCTs. Data were checked for accuracy. The certainty of the evidence for the main comparison (aspirin versus placebo) was assessed using the GRADE approach.

MAIN RESULTS

We included 17 RCTs, 16 of which randomised 1132 women to aspirin or placebo; one RCT did not report numbers of women. Two RCTs (of 16) did not contribute data to meta-analyses. All women had perineal pain post-episiotomy, and were not breastfeeding. Studies were published between 1967 and 1997, and the risk of bias was often unclear, due to poor reporting. We included four comparisons: aspirin versus placebo (15 RCTs); 300 mg versus 600 mg aspirin (1 RCT); 600 mg versus 1200 mg aspirin (2 RCTs); and 300 mg versus 1200 mg aspirin (1 RCT). Aspirin versus placebo Aspirin may result in more women reporting adequate pain relief four to eight hours after administration compared with placebo (risk ratio (RR) 2.03, 95% confidence interval (CI) 1.69 to 2.42; 13 RCTs, 1001 women; low-certainty evidence). It is uncertain whether aspirin compared with placebo has an effect on the need for additional pain relief (RR 0.25, 95% CI 0.17 to 0.37; 10 RCTs, 744 women; very low-certainty evidence), or maternal adverse effects (RR 1.08, 95% CI 0.57 to 2.06; 14 RCTs, 1067 women; very low-certainty evidence), four to eight hours after administration. Analyses based on dose did not reveal any clear subgroup differences. 300 mg versus 600 mg aspirin It is uncertain whether over four hours after administration, 300 mg compared with 600 mg aspirin has an effect on adequate pain relief (RR 0.82, 95% CI 0.36 to 1.86; 1 RCT, 81 women) or the need for additional pain relief (RR 0.68, 95% CI 0.12 to 3.88; 1 RCT, 81 women). There were no maternal adverse effects in either aspirin group. 600 mg versus 1200 mg aspirin It is uncertain whether over four to eight hours after administration, 600 mg compared with 1200 mg aspirin has an effect on adequate pain relief (RR 0.85, 95% CI 0.52 to 1.39; 2 RCTs, 121 women), the need for additional pain relief (RR 1.32, 95% CI 0.30 to 5.68; 2 RCTs, 121 women), or maternal adverse effects (RR 3.00, 95% CI 0.13 to 69.52; 2 RCTs, 121 women). 300 mg versus 1200 mg aspirin It is uncertain whether over four hours after administration, 300 mg compared with 1200 mg aspirin has an effect on adequate pain relief (RR 0.62, 95% CI 0.29 to 1.32; 1 RCT, 80 women) or need for additional pain relief (RR 2.00, 95% CI 0.19 to 21.18; 1 RCT, 80 women). There were no maternal adverse effects in either aspirin group. None of the included RCTs reported on neonatal adverse effects. No RCTs reported on secondary review outcomes of: prolonged hospitalisation due to perineal pain; re-hospitalisation due to perineal pain; fully breastfeeding at discharge; mixed feeding at discharge; fully breastfeeding at six weeks; mixed feeding at six weeks; perineal pain at six weeks; maternal views; or maternal postpartum depression.

AUTHORS' CONCLUSIONS

Single dose aspirin may increase adequate pain relief in women with perineal pain post-episiotomy compared with placebo. It is uncertain whether aspirin has an effect on the need for additional analgesia, or on maternal adverse effects, compared with placebo. We downgraded the certainty of the evidence because of study limitations (risk of bias), imprecision, and publication bias. Aspirin may be considered for use in non-breastfeeding women with post-episiotomy perineal pain. Included RCTs excluded breastfeeding women, so there was no evidence to assess the effects of aspirin on neonatal adverse effects or breastfeeding. Future RCTs should be designed to ensure low risk of bias, and address gaps in the evidence, such as the secondary outcomes established for this review. Current research has focused on women with post-episiotomy pain; future RCTs could be extended to include women with perineal pain associated with spontaneous tears or operative birth.

Diclofenac Potassium in Acute Postoperative Pain and Dysmenorrhoea: Results from Comprehensive Clinical Trial Reports

We compared the efficacy of diclofenac potassium in unpublished clinical study reports (CSRs) and published reports to examine publication bias, industry bias, and comprehensiveness. Novartis provided CSRs of randomised double-blind trials of diclofenac potassium involving postoperative patients following third molar extraction (3 trials, n=519), gynaecological surgery (3 trials, n=679), and dysmenorrhoea (2 trials, n=711) conducted in 1988–1990. Searches identified published reports of 6 trials. Information from 599/1909 patients was not published; trials with 846/1909 patients were published in a defunct journal. Greater methodological information in CSRs contributed to lesser risk of bias than published trials. Numbers needed to treat (NNT) from CSRs for all six postoperative trials for at least 50% of maximum pain relief over 6 h were 2.2 (95% confidence interval, 1.9–2.6) and 2.1 (1.8–2.4) for 50 and 100 mg diclofenac potassium, respectively. A Cochrane review of published trial data reported NNTs of 2.1 and 1.9, and one comprehensive analysis reported NNTs of 2.2 and 2.1, respectively. All analyses had similar results for patients remedicating within 8 h. No data from dysmenorrhoea CSRs appeared in a Cochrane review. CSRs provide useful information and increase confidence. Stable efficacy estimates with standard study designs reduce the need for updating reviews.

Aspirin (single dose) for perineal pain in the early postpartum period

BACKGROUND

Perineal trauma (due to spontaneous tears, surgical incision (episiotomy) or in association with operative vaginal birth) is common after vaginal birth, and is often associated with postpartum perineal pain. Birth over an intact perineum may also lead to perineal pain. There are adverse health consequences associated with perineal pain for the women and their babies in the short- and long-term, and the pain may interfere with newborn care and the establishment of breastfeeding. Aspirin has been used in the management of postpartum perineal pain and its effectiveness and safety should be assessed.

OBJECTIVES

To determine the efficacy of a single dose of aspirin (acetylsalicylic acid), including at different doses, in the relief of acute postpartum perineal pain.

SEARCH METHODS

We searched Cochrane Pregnancy and Childbirth's Trials Register (30 August 2016), ClinicalTrials.gov, the WHO International Clinical Trials Registry Platform (ICTRP) (31 May 2016) and reference lists of retrieved studies.

SELECTION CRITERIA

Randomised controlled trials (RCTs) assessing single dose aspirin compared with placebo, no treatment, a different dose of aspirin, or single dose paracetamol/acetaminophen for women with perineal pain in the early postpartum period. We planned to include cluster-RCTs but none were identified. Quasi-RCTs and cross-over studies were not eligible for inclusion in this review.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed study eligibility, extracted data and assessed the risk of bias of the included RCTs. Data were checked for accuracy. The quality of the evidence for the main comparison (aspirin versus placebo) was assessed using the GRADE approach.

MAIN RESULTS

We included 17 RCTs, with 16 involving 1132 women randomised to aspirin or placebo (one RCT did not report numbers of women). Two RCTs (of 16) did not contribute data to review meta-analyses. All women had perineal pain post-episiotomy, and were not breastfeeding. Studies were published between 1967 and 1997, and the risk of bias was often unclear due to poor reporting.We included four comparisons: aspirin versus placebo (data from 15 RCTs); 300 mg versus 600 mg aspirin (1 RCT); 600 mg versus 1200 mg aspirin (2 RCTs); and 300 mg versus 1200 mg aspirin (1 RCT). Primary outcomes Aspirin versus placeboMore women who received aspirin experienced adequate pain relief compared with women who received placebo over four to eight hours after administration (risk ratio (RR) 2.03, 95% confidence intervals (CI) 1.69 to 2.42; 13 RCTs, 1001 women; low-quality evidence). Women who received aspirin were less likely to need additional pain relief over four to eight hours after administration (RR 0.25, 95% CI 0.17 to 0.37; 10 RCTs, 744 women; very low-quality evidence). There was no difference in maternal adverse effects over four to eight hours post-administration (RR 1.08, 95% CI 0.57 to 2.06; 14 RCTs, 1067 women; very low-quality evidence). Subgroup analyses based on dose did not reveal any clear subgroup differences.There was no clear difference over four hours after administration between 300 mg and 600 mg aspirin for adequate pain relief (RR 0.82, 95% CI 0.36 to 1.86; 1 RCT, 81 women) or need for additional pain relief (RR 0.68, 95% CI 0.12 to 3.88; 1 RCT, 81 women). There were no maternal adverse effects in either aspirin group.There was no clear difference over four to eight hours after administration between 600 mg and 1200 mg aspirin for adequate pain relief (RR 0.85, 95% CI 0.52 to 1.39; 2 RCTs, 121 women), need for additional pain relief (RR 1.32, 95% CI 0.30 to 5.68; 2 RCTs, 121 women), or maternal adverse effects (RR 3.00, 95% CI 0.13 to 69.52; 2 RCTs, 121 women).There was no clear difference over four hours after administration between 300 mg and 1200 mg aspirin for adequate pain relief (RR 0.62, 95% CI 0.29 to 1.32; 1 RCT, 80 women) or need for additional pain relief (RR 2.00, 95% CI 0.19 to 21.18; 1 RCT, 80 women). There were no maternal adverse effects in either aspirin group.None of the included RCTs reported on neonatal adverse effects. Secondary outcomesNo studies reported on secondary review outcomes: prolonged hospitalisation due to perineal pain; re-hospitalisation due to perineal pain; fully breastfeeding at discharge; mixed feeding at discharge; fully breastfeeding at six weeks; mixed feeding at six weeks; perineal pain at six weeks; maternal views; maternal postpartum depression.

AUTHORS' CONCLUSIONS

We found low-quality evidence to suggest that single dose aspirin compared with placebo can increase pain relief in women with perineal pain post-episiotomy. Very low-quality evidence also suggested that aspirin can reduce the need for additional analgesia, without increasing maternal adverse effects. Evidence was downgraded based on study limitations (risk of bias), imprecision, and publication bias or both. RCTs excluded breastfeeding women so there is no evidence to assess the effects of aspirin on neonatal adverse effects or breastfeeding.With international guidance recommending mothers initiate breastfeeding within one hour of birth, and exclusively breastfeed for the first six months, the evidence from this review is not applicable to current recommended best practice. Aspirin may be considered for use in non-breastfeeding women with post-episiotomy perineal pain. Although formal assessment was beyond the remit of this review, current guidance suggests that other analgesic drugs (including paracetamol) should be considered first for postpartum perineal pain. Such agents are the focus of other reviews in this series on drugs for perineal pain in the early postpartum period. It is considered most likely that if RCTs are conducted in the future they could compare aspirin with other pain relievers. Future RCTs should be designed to ensure high methodological quality, and address gaps in the evidence, such as the secondary outcomes established for this review. Current research has focused on women with post-episiotomy pain, future RCTs could be extended to women with perineal pain associated with spontaneous tears or operative birth.

Oral non-steroidal anti-inflammatory drugs (single dose) for perineal pain in the early postpartum period

BACKGROUND

Many women experience perineal pain after childbirth, especially after having sustained perineal trauma. Perineal pain-management strategies are thus an important part of postnatal care. Non-steroidal anti-inflammatory drugs (NSAIDs) are a commonly used type of medication in the management of postpartum pain and their effectiveness and safety should be assessed.

OBJECTIVES

To determine the effectiveness of a single dose of an oral NSAID for relief of acute perineal pain in the early postpartum period.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (31 March 2016), OpenSIGLE, ProQuest Dissertations and Theses, the ISRCTN Registry and ClinicalTrials.gov (31 March 2016). We also reviewed reference lists of retrieved papers and contacted experts in the field.

SELECTION CRITERIA

Randomised controlled trials (RCTs) assessing a single dose of a NSAID versus a single dose of placebo, paracetamol or another NSAID for women with perineal pain in the early postpartum period. Quasi-RCTs and cross-over trials were excluded.

DATA COLLECTION AND ANALYSIS

Two review authors (FW and VS) independently assessed all identified papers for inclusion and risk of bias. Any discrepancies were resolved through discussion and consensus. Data extraction, including calculations of pain relief scores, was also conducted independently by two review authors and checked for accuracy.

MAIN RESULTS

We included 28 studies that examined 13 different NSAIDs and involved 4181 women (none of whom were breastfeeding). Studies were published between 1967 and 2013, with the majority published in the 1980s. Of the 4181 women involved in the studies, 2642 received a NSAID and 1539 received placebo or paracetamol. Risk of bias was generally unclear due to poor reporting, but in most studies the participants and personnel were blinded, outcome data were complete and the outcomes that were specified in the methods section were reported.None of the included studies reported on any of this review's secondary outcomes: prolonged hospitalisation or re-hospitalisation due to perineal pain; breastfeeding (fully or mixed) at discharge; breastfeeding (fully or mixed) at six weeks; perineal pain at six weeks; maternal views; postpartum depression; instrumental measures of disability due to perineal pain. NSAID versus placeboCompared to women who received a placebo, more women who received a single dose NSAID achieved adequate pain relief at four hours (risk ratio (RR) 1.91, 95% confidence interval (CI) 1.64 to 2.23, 10 studies, 1573 participants (low-quality evidence)) and adequate pain relief at six hours (RR 1.92, 95% CI 1.69 to 2.17, 17 studies, 2079 participants (very low-quality evidence)). Women who received a NSAID were also less likely to need additional analgesia compared to women who received placebo at four hours (RR 0.39, 95% CI 0.26 to 0.58, four studies, 486 participants (low-quality evidence)) and at six hours after initial administration (RR 0.32, 95% CI 0.26 to 0.40, 10 studies, 1012 participants (low-quality evidence)). Fourteen maternal adverse effects were reported in the NSAID group (drowsiness (5), abdominal discomfort (2), weakness (1), dizziness (2), headache (2), moderate epigastralgia (1), not specified (1)) and eight in the placebo group (drowsiness (2), light headed (1), nausea (1), backache (1), dizziness (1), epigastric pain (1), not specified (1)), although not all studies assessed adverse effects. There was no difference in overall maternal adverse effects between NSAIDs and placebo at six hours post-administration (RR 1.38, 95% CI 0.71 to 2.70, 13 studies, 1388 participants (very low-quality evidence)). One small study (with two treatment arms) assessed maternal adverse effects at four hours post-administration, but there were no maternal adverse effects observed (one study, 90 participants (low-quality evidence)). Neonatal adverse effects were not assessed in any of the included studies. NSAID versus paracetamolNSAIDs versus paracetamol were also more effective for adequate pain relief at four hours (RR 1.54, 95% CI 1.07 to 2.22, three studies, 342 participants) but not at six hours post-administration. There was no difference in the need for additional analgesia between the two groups at four hours (RR 0.55, 95% CI 0.27 to 1.13, one study, 73 participants), but women in the NSAID group were less likely to need any additional analgesia at six hours (RR 0.28, 95% CI 0.12 to 0.67, one study, 59 participants). No maternal adverse effects were reported four hours after drug administration (one study). Six hours post-administration, there was no difference between the groups in the number of maternal adverse effects (RR 0.74, 95% CI 0.27 to 2.08, three studies, 300 participants), with one case of pruritis in the NSAID group and one case of sleepiness in the paracetamol group. Neonatal adverse effects were not assessed in any of the included studies.Comparisons of different NSAIDs and different doses of the same NSAID did not demonstrate any differences in their effectiveness on any of the primary outcome measures; however, few data were available on some NSAIDs.

AUTHORS' CONCLUSIONS

In women who are not breastfeeding and who sustained perineal trauma, NSAIDs (compared to placebo) provide greater pain relief for acute postpartum perineal pain and fewer women need additional analgesia when treated with a NSAID. However, the risk of bias was unclear for many of the included studies, adverse effects were often not assessed and breastfeeding women were not included in the studies. The overall quality of the evidence (GRADE) was low with the evidence for all outcomes rated as low or very low. The main reasons for downgrading were inclusion of studies with high risk of bias and inconsistency of findings of individual studies.NSAIDs also appear to be more effective in providing relief for perineal pain than paracetamol, but few studies were included in this analysis.Future studies should examine NSAIDs' adverse effects profile including neonatal adverse effects and the compatibility of NSAIDs with breastfeeding, and assess other important secondary outcomes of this review. Moreover, studies mostly included women who had episiotomies. Future research should consider women with and without perineal trauma, including perineal tears. High-quality studies should be conducted to further assess the efficacy of NSAIDs versus paracetamol and the efficacy of multimodal treatments.

Single dose oral diclofenac for acute postoperative pain in adults

BACKGROUND

Diclofenac is a nonsteroidal anti-inflammatory drug, available as a potassium salt (immediate release) or sodium salt (enteric coated to suppress dissolution in the stomach). This review updates an earlier review published in the Cochrane Database of Systematic Reviews (Issue 2, 2009) entitled 'Single dose oral diclofenac for acute postoperative pain in adults'.

OBJECTIVES

To assess the analgesic efficacy and adverse effects of a single oral dose of diclofenac for moderate to severe postoperative pain, using methods that permit comparison with other analgesics evaluated in standardised trials using almost identical methods and outcomes.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, the Oxford Pain Relief Database, two clinical trial registries, and the reference lists of articles. The date of the most recent search was 9 March 2015.

SELECTION CRITERIA

Randomised, double-blind, placebo-controlled clinical trials of single dose, oral diclofenac (sodium or potassium) for acute postoperative pain in adults.

DATA COLLECTION AND ANALYSIS

Two review authors independently considered studies for inclusion in the review, assessed risk of bias, and extracted data. We used the area under the pain relief versus time curve to derive the proportion of participants with at least 50% pain relief over six hours prescribed either diclofenac or placebo. We calculated the risk ratio (RR) and number needed to treat to benefit (NNT). We used information on the use of rescue medication to calculate the proportion of participants requiring rescue medication and the weighted mean of the median time to use. We also collected information on adverse effects.

MAIN RESULTS

This update included three new studies, providing a 26% increase in participants in comparisons between diclofenac and placebo. We included 18 studies involving 3714 participants, 1902 treated with diclofenac and 1007 with placebo. This update has also changed the focus of the review, examining the effects of formulation in more detail than previously. This is a result of increased understanding of the importance of speed of onset in determining analgesic efficacy in acute pain.The largest body of information, for diclofenac potassium 50 mg, in seven studies, produced an NNT for at least 50% of maximum pain relief compared with placebo of 2.1 (95% confidence interval (CI) 1.9 to 2.5) (high quality evidence). There was a graded improvement in efficacy as doses rose from 25 mg to 100 mg, both for participants achieving at least 50% maximum pain relief, and for remedication within 6 to 8 hours. Fast-acting formulations (dispersible products, solutions, and softgel formulations) had a similar efficacy for a 50 mg dose, with an NNT of 2.4 (2.0 to 3.0). Diclofenac sodium in a small number of studies produced a lesser effect, with an NNT of 6.6 (4.1 to 17) for the 50 mg dose.Adverse event rates were low in these single dose studies, with no difference between diclofenac and placebo (moderate quality evidence).

AUTHORS' CONCLUSIONS

Diclofenac potassium provides good pain relief at 25 mg, 50 mg, and 100 mg doses. Diclofenac sodium has limited efficacy and should probably not be used in acute pain.

Advances in NSAID development: evolution of diclofenac products using pharmaceutical technology

Diclofenac is a nonsteroidal anti-inflammatory drug (NSAID) of the phenylacetic acid class with anti-inflammatory, analgesic, and antipyretic properties. Contrary to the action of many traditional NSAIDs, diclofenac inhibits cyclooxygenase (COX)-2 enzyme with greater potency than it does COX-1. Similar to other NSAIDs, diclofenac is associated with serious dose-dependent gastrointestinal, cardiovascular, and renal adverse effects. Since its introduction in 1973, a number of different diclofenac-containing drug products have been developed with the goal of improving efficacy, tolerability, and patient convenience. Delayed- and extended-release forms of diclofenac sodium were initially developed with the goal of improving the safety profile of diclofenac and providing convenient, once-daily dosing for the treatment of patients with chronic pain. New drug products consisting of diclofenac potassium salt were associated with faster absorption and rapid onset of pain relief. These include diclofenac potassium immediate-release tablets, diclofenac potassium liquid-filled soft gel capsules, and diclofenac potassium powder for oral solution. The advent of topical formulations of diclofenac enabled local treatment of pain and inflammation while minimizing systemic absorption of diclofenac. SoluMatrix diclofenac, consisting of submicron particles of diclofenac free acid and a proprietary combination of excipients, was developed to provide analgesic efficacy at reduced doses associated with lower systemic absorption. This review illustrates how pharmaceutical technology has been used to modify the pharmacokinetic properties of diclofenac, leading to the creation of novel drug products with improved clinical utility.

Development and validation of a dissolution method using HPLC for diclofenac potassium in oral suspension

The present study describes the development and validation of an in vitro dissolution method for evaluation to release diclofenac potassium in oral suspension. The dissolution test was developed and validated according to international guidelines. Parameters like linearity, specificity, precision and accuracy were evaluated, as well as the influence of rotation speed and surfactant concentration on the medium. After selecting the best conditions, the method was validated using apparatus 2 (paddle), 50-rpm rotation speed, 900 mL of water with 0.3% sodium lauryl sulfate (SLS) as dissolution medium at 37.0 ± 0.5°C. Samples were analyzed using the HPLC-UV (PDA) method. The results obtained were satisfactory for the parameters evaluated. The method developed may be useful in routine quality control for pharmaceutical industries that produce oral suspensions containing diclofenac potassium.

Design of biorelevant test setups for the prediction of diclofenac in vivo features after oral administration

PURPOSE

Design of biorelevant test setups mimicking the physiological conditions experienced by drugs after oral administration along the passage through the mouth and the GI tract for the in vitro evaluation of diclofenac exhibiting multiple-peak phenomenon during absorption.

METHODS

The biorelevant models simulated successively saliva (SSF, pH 6.2-6.75-7.4, 5 mL, 3 min), gastric (SGF-FaSSGF, pH 1.2-1.6, 50-250 mL, 30 min) and intestinal (FaSSIF, pH 6.8, 250 mL, 60 min) fluids. Applying these models, diclofenac free acid and its sodium/potassium salt were comparatively evaluated for dissolution and further characterized by HPLC, optical morphogranulometry, DSC and PXRD to elucidate peculiar behaviors.

RESULTS

Diclofenac salts almost completely dissolved in SSF and showed a transitional dissolution pattern before complete precipitation in SGF/FaSSGF. This peculiar pattern correlated with simultaneous chemical modification and formation of agglomerates. With low dissolution in SSF and almost immediately complete precipitation, these behaviors were not observed with diclofenac free acid. Distinct diclofenac features were strongly determined by pH-modifications after oral administration.

CONCLUSIONS

The multiple-peak phenomenon observed after administrating a solution, suspension or dispersible formulation of diclofenac salts are likely caused by drug precipitation and agglomeration in the stomach leading to irregular gastric-emptying. Diclofenac free acid may provide more reliable in vivo features.

Paracetamol/acetaminophen (single administration) for perineal pain in the early postpartum period

BACKGROUND

Perineal pain is a common but poorly studied adverse outcome following childbirth. Pain may result from perineal trauma due to bruising, spontaneous tears, surgical incisions (episiotomies), or in association with operative births (ventouse or forceps assisted births).

OBJECTIVES

To determine the efficacy of a single administration of paracetamol (acetaminophen) systemic drugs used in the relief of acute postpartum perineal pain

SEARCH METHODS

We updated the search of the Cochrane Pregnancy and Childbirth Group's Trials Register on 6 November 2012.

SELECTION CRITERIA

Randomised controlled trials (RCTs) assessing paracetamol (acetaminophen) in a single dose compared with placebo for women with early postpartum perineal pain. We excluded quasi-RCTs and cross-over studies.

DATA COLLECTION AND ANALYSIS

Two review authors assessed each paper for inclusion and extracted data. One review author reviewed the decisions and confirmed calculations for pain relief scores.

MAIN RESULTS

We did not identify any new trials from the updated search so the results remain unchanged as follows.We have included 10 studies describing two dosages of paracetamol. Of these, five studies (526 women) assessed 500 mg to 650 mg and six studies (841 women) assessed 1000 mg of paracetamol. We chose to use random-effects meta-analyses because of the heterogeneity in dosage used. Studies were from the 1970s to the early 1990s, and there was insufficient information to assess the risk of bias adequately, hence the findings need to be interpreted within this context.More women experienced pain relief with paracetamol compared with placebo (average risk ratio (RR) 2.14, 95% confidence interval (CI) 1.59 to 2.89, 10 studies, 1279 women). In addition, there were significantly fewer women having additional pain relief with paracetamol compared with placebo (RR 0.34, 95% CI 0.21 to 0.55, eight studies, 1132 women). Both the 500 mg to 650 mg and 1000 mg doses were effective in providing more pain relief than placebo.Maternal and neonatal potential adverse drug effects were not assessed in any of the included studies. Indeed few secondary outcomes were assessed.

AUTHORS' CONCLUSIONS

More women experienced pain relief, and fewer had additional pain relief, with paracetamol compared with placebo, although potential adverse effects were not assessed and generally the quality of studies was unclear.

Single dose oral aspirin for acute postoperative pain in adults

BACKGROUND

This review is an update of a previously published review in the Cochrane Database of Systematic Reviews on 'Single dose oral aspirin for acute pain'. Aspirin has been known for many years to be an effective analgesic for many different pain conditions. Although its use as an analgesic is now limited in developed countries, it is widely available, inexpensive, and remains commonly used throughout the world.

OBJECTIVES

To assess the analgesic efficacy and associated adverse events of single dose oral aspirin in acute postoperative pain.

SEARCH METHODS

For the earlier review, we identified randomised trials by searching CENTRAL (The Cochrane Library) (1998, Issue 1), MEDLINE (1966 to March 1998), EMBASE (1980 to January 1998), and the Oxford Pain Relief Database (1950 to 1994). We updated searches of CENTRAL, MEDLINE, and EMBASE to January 2012.

SELECTION CRITERIA

Single oral dose, randomised, double-blind, placebo-controlled trials of aspirin for relief of established moderate to severe postoperative pain in adults.

DATA COLLECTION AND ANALYSIS

We assessed studies for methodological quality and two review authors extracted the data independently. We used summed total pain relief (TOTPAR) over four to six hours to calculate the number of participants achieving at least 50% pain relief. We used these derived results to calculate, with 95% confidence intervals, the relative benefit compared to placebo, and the number needed to treat (NNT) for one participant to experience at least 50% pain relief over four to six hours. We sought numbers of participants using rescue medication over specified time periods, and time to use of rescue medication, as additional measures of efficacy. We collected information on adverse events and withdrawals.

MAIN RESULTS

We included 68 studies in which aspirin was used at doses from 300 mg to 1200 mg, but the vast majority of participants received either 600/650 mg (2409 participants, 64 studies) or 990/1000 mg (380 participants, eight studies). There was only one new study.Studies were overwhelmingly of adequate or good methodological quality. NNTs for at least 50% pain relief over four to six hours were 4.2 (3.9 to 4.8), 3.8 (3.0 to 5.1), and 2.7 (2.0 to 3.8) for 600/650 mg, 900/1000 mg, and 1200 mg respectively, compared with placebo. Type of pain model had no significant impact on the results. Lower doses were not significantly different from placebo. These results do not differ from those of the earlier review.Fewer participants required rescue medication with aspirin than with placebo over four to eight hours postdose, but by 12 hours there was no difference. The number of participants experiencing adverse events was not significantly different from placebo for 600/650 mg aspirin, but for 900/1000 mg the number needed to treat to harm was 7.5 (4.8 to 17). The most commonly reported events were dizziness, drowsiness, gastric irritation, nausea, and vomiting, nearly all of which were of mild to moderate severity.

AUTHORS' CONCLUSIONS

Aspirin is an effective analgesic for acute pain of moderate to severe intensity. High doses are more effective, but are associated with increased adverse events, including drowsiness and gastric irritation. The pain relief achieved with aspirin was very similar milligram for milligram to that seen with paracetamol. There was no change to the conclusions in this update.

Efficacy and tolerability of a new powdered formulation of diclofenac potassium for oral solution for the acute treatment of migraine: results from the International Migraine Pain Assessment Clinical Trial (IMPACT)

OBJECTIVE

This study assessed the efficacy of diclofenac potassium for oral solution, a novel water-soluble buffered powder formulation, versus placebo for the acute treatment of migraine. Diclofenac potassium for oral solution has a time to maximum plasma concentration (Tmax) of 15 minutes, suggesting the potential for a rapid onset of therapeutic effects.

METHODS

This was a randomized, double-blind, parallel-group, placebo-controlled study conducted in 23 US centers. Adult sufferers with an established migraine diagnosis according to the International Classification of Headache Disorders, second edition (ICHD-II), treated one moderate or severe attack with 50 mg diclofenac potassium for oral solution (dissolved in approximately 2 ounces of water; N=343) or matching placebo (N=347). Four co-primary endpoints included the percentage of subjects who at two hours post-treatment reported no headache pain, no nausea, no photophobia and/or no phonophobia.

RESULTS

Significantly more subjects treated with diclofenac potassium for oral solution (N=343) achieved a two-hour pain-free response (25% vs. 10%, p<.001), no nausea (65% vs. 53%; p=.002), no photophobia (41% vs. 27%; p<.001) and no phonophobia (44% vs. 27%; p<.001) compared to placebo. Pain intensity differences between treatments were significantly lower in the diclofenac potassium oral solution group, starting at 30 minutes post-treatment (p=.013) with significant differences at all time points thereafter (p<.001). Twenty-four-hour sustained pain-free response favored diclofenac potassium oral solution treatment versus placebo (19% vs. 7%, p<.0001). The most common adverse event considered to be treatment related was nausea (diclofenac potassium for oral solution [4.6%]; placebo [4.3%]).

CONCLUSIONS

This study shows that this formulation of diclofenac potassium for oral solution is effective in reducing pain intensity within 30 minutes, which may be related to the 15-minute T(max) associated with this formulation. The rapid-onset benefits were sustained through 24 hours post-treatment.

Paracetamol/acetaminophen (single administration) for perineal pain in the early postpartum period

BACKGROUND

Perineal pain is a common but poorly studied adverse outcome following childbirth. Pain may result from perineal trauma due to bruising, spontaneous tears, surgical incisions (episiotomies), or in association with operative births (ventouse or forceps assisted births).

OBJECTIVES

To determine the efficacy of a single administration of paracetamol (acetaminophen) systemic drugs used in the relief of acute postpartum perineal pain

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (December 2009).

SELECTION CRITERIA

Randomised controlled trials (RCTs) assessing paracetamol (acetaminophen) in a single dose compared with placebo for women with early postpartum perineal pain. We excluded quasi-RCTs and cross-over studies.

DATA COLLECTION AND ANALYSIS

Two review authors assessed each paper for inclusion and extracted data. One review author reviewed the decisions and confirmed calculations for pain relief scores.

MAIN RESULTS

We have included 10 studies describing two dosages of paracetamol. Of these, five studies (526 women) assessed 500 mg to 650 mg and six studies (841 women) assessed 1000 mg of paracetamol. We chose to use random-effects meta-analyses because of the heterogeneity in dosage used. Studies were from the 1970s to the early 1990s, and there was insufficient information to assess the risk of bias adequately, hence the findings need to be interpreted within this context.More women experienced pain relief with paracetamol compared with placebo (average risk ratio (RR) 2.14, 95% confidence interval (CI) 1.59 to 2.89, 10 studies, 1279 women). In addition, there were significantly fewer women having additional pain relief with paracetamol compared with placebo (RR 0.34, 95% CI 0.21 to 0.55, eight studies, 1132 women). Both the 500 mg to 650 mg and 1000 mg doses were effective in providing more pain relief than placebo.Maternal and neonatal potential adverse drug effects were not assessed in any of the included studies. Indeed few secondary outcomes were assessed.

AUTHORS' CONCLUSIONS

More women experienced pain relief, and fewer had additional pain relief, with paracetamol compared with placebo, although potential adverse effects were not assessed and generally the quality of studies was unclear.

Single dose oral diclofenac for acute postoperative pain in adults

BACKGROUND

Diclofenac is a non-steroidal anti-inflammatory drug (NSAID), available as a potassium salt (immediate-release) or sodium salt (delayed-release). This review updates an earlier review published in The Cochrane Database of Systematic Reviews (Issue 2, 2004) on 'Single dose oral diclofenac for postoperative pain'.

OBJECTIVES

To assess single dose oral diclofenac for the treatment of acute postoperative pain.

SEARCH STRATEGY

Cochrane CENTRAL, MEDLINE, EMBASE, Biological Abstracts, the Oxford Pain Relief Database, and reference lists of articles were searched; last search December 2008.

SELECTION CRITERIA

Randomised, double-blind, placebo-controlled clinical trials of single dose, oral diclofenac (sodium or potassium) for acute postoperative pain in adults.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed studies for inclusion and quality, and extracted data. The area under the pain relief versus time curve was used to derive the proportion of participants with at least 50% pain relief over 4 to 6 hours, using validated equations. Relative benefit (risk) and number needed to treat to benefit (NNT) were calculated. Information on adverse events, time to remedication, and participants needing additional analgesia was also collected.

MAIN RESULTS

Fifteen studies (eight additional studies) with 1512 participants more than doubled the information available at each dose. Overall 50% to 60% of participants experienced at least 50% pain relief over 4 to 6 hours at any dose with diclofenac, compared to 10 to 20% with placebo, giving NNTs of about 2.5 for doses of 25 mg to 100 mg (similar to earlier review); no dose response was demonstrated. At 50 mg and 100 mg, NNTs for diclofenac potassium (2.1 (1.8 to 2.4) and 1.9 (1.7 to 2.2)) were significantly lower (better) than for diclofenac sodium (6.7 (4.2 to 17) and 4.5 (3.2 to 7.7)). The median time to use of rescue medication was 2 hours for placebo, 4.3 hours for diclofenac 50 mg and 4.9 hours for diclofenac 100 mg. Adverse events were reported at a similar rate to placebo, with no serious events.

AUTHORS' CONCLUSIONS

Oral diclofenac is an effective single-dose treatment for moderate to severe postoperative pain. Significantly more participants experienced at least 50% pain relief over 4 to 6 hours with diclofenac potassium than with diclofenac sodium. There was no significant difference between diclofenac and placebo in the incidence of adverse events.

Diclofenac potassium 12.5mg tablets for mild to moderate pain and fever: a review of its pharmacology, clinical efficacy and safety

Non-prescription (over-the-counter [OTC]) analgesics are used for the short-term treatment of acute painful conditions of mild to moderate intensity in everyday life. Well documented safety and efficacy, a rapid onset of action and a flexible daily dosing regimen are essential in this context. Film-coated, immediate-release, low-dose diclofenac potassium, developed for OTC use, offers a flexible daily dosing regimen with an initial dose of two tablets (2 x 12.5mg) followed by one or two tablets up to a maximum daily dose of six tablets (75 mg/day). The maximum plasma drug concentration is reached 30 minutes after administration, and the mean terminal half-life is 1-2 hours, allowing a 4- to 6-hour duration of activity, depending on the condition. Thirteen randomised, double-blind trials with both placebo and active controls have demonstrated the efficacy of diclofenac potassium 12.5mg tablets in conditions suitable for treatment with OTC medication, for example, acute lower back pain, headache, acute pain after dental extraction, symptoms of cold and influenza (including fever), and dysmenorrhoea. A single dose of diclofenac potassium 12.5mg is the lowest recommended effective dose. A two-tablet single dose of 25mg is at least as effective as ibuprofen 400mg. A flexible dosing regimen of an initial two tablets followed by one or two tablets up to a total daily dose of 75 mg is as effective as ibuprofen used in comparable fashion up to a total daily dose of 1200 mg. The incidence of adverse events in patients taking single or multiple doses of diclofenac potassium is similar to that of ibuprofen and placebo. In a safety study conducted to compare diclofenac potassium with ibuprofen for up to 3 months in patients with osteoarthritis of the knee, no differences in the pattern of adverse events were noted. There was no evidence of either hepatic injury or cardiovascular safety-related issues at any time during the study. Patients are generally capable of taking diclofenac potassium appropriately. A maximum OTC treatment duration of 5 days for pain and 3 days for fever is recommended.

Wirksamkeit und Wirkungsbeginn von Pregabalin bei Patienten mit neuropathischen Schmerzen

BACKGROUND

The data from a previously published 12-week randomised, double-blind, placebo-controlled multicentre study on the efficacy and safety of pregabalin were analyzed for time to onset of analgesic action with neuropathic pain.

PATIENTS AND METHODS

A total of 338 patients with postherpetic neuralgia or painful diabetic peripheral neuropathy were treated with flexible or fixed regimens of pregabalin at daily doses of up to 600 mg/day (n=141 and 132, respectively) or placebo (n=65).

RESULTS

Under fixed dose treatment, a decrease of one full point on the 11-point numerical rating pain scale was reached on day 1, two full points on day 13, and three full points on day 23 (under flexible dose pregabalin: on days 6, 17 and 30). In both treatment arms, pain reduction was statistically significant (P=0.001, P=0.002 vs placebo, respectively).

CONCLUSION

In patients with chronic neuropathic pain, the analgesic effect of both pregabalin treatment regimens was high and associated with a rapid time to onset.

Diclofenac pyrrolidine versus Ketoprofen for the relief of pain from episiotomy: A randomized controlled trial

BACKGROUND

The treatment of pain from episiotomy or from tearing of perineal tissues during childbirth is often unapplied, although discomfort may be severe. We performed a randomized double-blind controlled trial to compare the effectiveness and side-effects of two analgesics in the management of postpartum perineal pain. Patient preference toward the two medications was also analyzed.

METHODS

A total of 261 women were randomly assigned to receive either Diclofenac hydroxyethyl pyrrolidine (100 mg) (n = 133) or Ketoprofen (100 mg) (n = 128), both given orally every 12 hr up to 48 hr, as necessary. Inclusion criteria were vaginal birth with episiotomy and/or a second- to third-degree tear. Pain ratings were recorded before the administration of the drugs and at 1, 4, 12, and 24 hr after the first dose, according to a 10-cm visual-analog scale. Side-effects and overall opinion on the two treatments were assessed at 24 hr.

RESULTS

Diclofenac hydroxyethyl pyrrolidine and Ketoprofen had similar analgesic properties in the first 24 hr postpartum [mean pain rating 3.1 +/- 1.8 and 3.4 +/- 2.0, mean number of doses in 24 hr 1.4 +/- 1.4 and 1.3 +/- 1.5, and proportion of treatment failures 12.8% (17/133) and 16.4% (21/128), respectively]. Significantly fewer subjects in the Diclofenac hydroxyethyl pyrrolidine group than in the Ketoprofen group experienced side-effects (6.8% versus 15.6%; p = 0.038) with an odd risk = 0.39(95% C.I. 0.16-0.95). There were no significant differences in overall patient satisfaction between the two groups.

CONCLUSIONS

No main differences were found concerning the relief of pain between the two treatments. Diclofenac hydroxyethyl pyrrolidine may be the preferred choice because it is associated with less adverse reactions, together with a faster action in the relief of pain.

Bioavailability of diclofenac potassium at low doses

AIM

Diclofenac-K has been recently launched at low oral doses in different countries for over-the-counter use. However, given the considerable first-pass metabolism of diclofenac, the degree of absorption of diclofenac-K at low doses remained to be determined. The aim of this study was to determine the bioavailability of low-dose diclofenac-K.

METHODS

A randomized, three-way, cross-over study was performed in 10 subjects. Each received diclofenac-K, 22.5 mg via short-term i.v. infusion and orally at single doses of 12.5 mg and 25 mg.

RESULTS

Mean (+/- SD) times to maximal plasma concentration (t(max)) of diclofenac were 0.48 +/- 0.28 h (12.5 mg) and 0.93 +/- 0.96 h (25 mg). The absolute bioavailability of diclofenac-K after oral administration did not differ significantly in the 12.5-mg and 25-mg dose group (63.1 +/- 12.6%vs. 65.1 +/- 19.4%, respectively). The 90% confidence intervals for the AUC(infinity) and AUC(t) ratios for the two oral regimes were 82.6, 103.4% (point estimate 92.4%) and 86.2, 112.9% (point estimate 98.6%), respectively. These values were within the acceptance criteria for bioequivalence (80-125%).

CONCLUSIONS

Our data indicate that diclofenac-K is rapidly and well absorbed at low dose, and are consistent with a rapid onset of action of the drug. Abbreviations AUC, area under plasma concentration-time curve; C(max), peak plasma concentration; CI, confidence interval; COX, cyclooxygenase; D, dose; F, absolute bioavailability; t(max), time to reach C(max).

Single dose oral diclofenac for postoperative pain

BACKGROUND

Diclofenac is a benzene-acetic acid derivative that acts, like other NSAIDs, by inhibiting cyclo-oxygenase isoforms that mediate the body's production of the prostaglandins implicated in pain and inflammation. Diclofenac is widely available as a sodium or potassium salt. Diclofenac potassium tablets are known as 'immediate-release' diclofenac as absorption takes place in the gastrointestinal tract whereas 'delayed-release' (enteric-coated) diclofenac tablets resist dissolution until reaching the duodenum. An existing review showed that diclofenac was an effective treatment for acute postoperative pain but did not address the distinction between potassium and sodium salts due to lack of data. The aim of this update is to gather and add appropriate information published subsequently and, data permitting, examine any potential differences between the two different diclofenac formulations.

OBJECTIVES

To assess single dose oral diclofenac for the treatment of acute postoperative pain and determine whether there are differences between the different formulations.

SEARCH STRATEGY

We searched the Cochrane Library (Issue 2, 2003), MEDLINE (1966 to May 1996), EMBASE (1980 to 1996), Biological Abstracts (1985 to 2003), the Oxford Pain Relief Database (1950 to 1994), PubMed (1996 to 2003) and reference lists of articles.

SELECTION CRITERIA

Randomised, double-blind, placebo-controlled clinical trials of single dose, oral diclofenac sodium or diclofenac potassium for acute postoperative pain in adults.

DATA COLLECTION AND ANALYSIS

Two reviewers independently assessed trials for inclusion in the review, quality and extracted data. The area under the pain relief versus time curve was used to derive the proportion of patients prescribed diclofenac or placebo with at least 50% pain relief over four to six hours using validated equations. The number needed to treat (NNT) was calculated. Information on adverse effects was also collected.

MAIN RESULTS

One additional trial was included and added to the six trials included in the original review. All seven trials provided data for quantitative analysis: 581 patients were treated with diclofenac and 364 were treated with placebo. The NNT for at least 50% relief over four to six hours with diclofenac 25 mg, 50 mg and 100 mg compared with placebo was 2.8 (95% CI 2.1 to 4.3), 2.3 (2.0 to 2.7) and 1.9 (1.6 to 2.2) respectively. Though higher doses produced lower (better) NNTs, statistical significance was not achieved. There was no significant difference between diclofenac 50 mg and placebo in the proportion of patients experiencing dizziness, headache, nausea or vomiting. The weighted median duration of analgesia was 2 hours for placebo, 6.7 hours for diclofenac 50 mg and 7.2 hours for diclofenac 100 mg. Sensitivity analyses for drug formulation, pain model, trial size and quality did not reveal any statistically significant differences.

REVIEWERS' CONCLUSIONS

Oral diclofenac is an effective single-dose treatment for moderate to severe postoperative pain. There was no significant difference between diclofenac and placebo in the incidence of adverse effects, or between diclofenac sodium and potassium, different pain models, smaller and larger trials and trials of higher and lower quality.