A comparative study of intramuscular ketorolac and pethidine in labour pain

Parenteral opioids for maternal pain management in labour

BACKGROUND

Parenteral opioids (intramuscular and intravenous drugs including patient-controlled analgesia) are used for pain relief in labour in many countries throughout the world. This review is an update of a review first published in 2010.

OBJECTIVES

To assess the effectiveness, safety and acceptability to women of different types, doses and modes of administration of parenteral opioid analgesia in labour. A second objective is to assess the effects of opioids in labour on the baby in terms of safety, condition at birth and early feeding.

SEARCH METHODS

We searched Cochrane Pregnancy and Childbirth's Trials Register, ClinicalTrials.gov, the WHO International Clinical Trials Registry Platform (ICTRP) (11 May 2017) and reference lists of retrieved studies.

SELECTION CRITERIA

We included randomised controlled trials examining the use of intramuscular or intravenous opioids (including patient-controlled analgesia) for women in labour. Cluster-randomised trials were also eligible for inclusion, although none were identified. We did not include quasi-randomised trials. We looked at studies comparing an opioid with another opioid, placebo, no treatment, other non-pharmacological interventions (transcutaneous electrical nerve stimulation (TENS)) or inhaled analgesia.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trials for inclusion and risk of bias, extracted data and checked them for accuracy. We assessed the quality of each evidence synthesis using the GRADE approach.

MAIN RESULTS

We included 70 studies that compared an opioid with placebo or no treatment, another opioid administered intramuscularly or intravenously or compared with TENS applied to the back. Sixty-one studies involving more than 8000 women contributed data to the review and these studies reported on 34 different comparisons; for many comparisons and outcomes only one study contributed data. All of the studies were conducted in hospital settings, on healthy women with uncomplicated pregnancies at 37 to 42 weeks' gestation. We excluded studies focusing on women with pre-eclampsia or pre-existing conditions or with a compromised fetus. Overall, the evidence was graded as low- or very low-quality regarding the analgesic effect of opioids and satisfaction with analgesia; evidence was downgraded because of study design limitations, and many of the studies were underpowered to detect differences between groups and so effect estimates were imprecise. Due to the large number of different comparisons, it was not possible to present GRADE findings for every comparison.For the comparison of intramuscular pethidine (50 mg/100 mg) versus placebo, no clear differences were found in maternal satisfaction with analgesia measured during labour (number of women satisfied or very satisfied after 30 minutes: 50 women; 1 trial; risk ratio (RR) 7.00, 95% confidence interval (CI) 0.38 to 128.87, very low-quality evidence), or number of women requesting an epidural (50 women; 1 trial; RR 0.50, 95% CI 0.14 to 1.78; very low-quality evidence). Pain scores (reduction in visual analogue scale (VAS) score of at least 40 mm: 50 women; 1 trial; RR 25, 95% CI 1.56 to 400, low-quality evidence) and pain measured in labour (women reporting pain relief to be "good" or "fair" within one hour of administration: 116 women; 1 trial; RR 1.75, 95% CI 1.24 to 2.47, low-quality evidence) were both reduced in the pethidine group, and fewer women requested any additional analgesia (50 women; 1 trial; RR 0.71, 95% CI 0.54 to 0.94, low-quality evidence).There was limited information on adverse effects and harm to women and babies. There were few results that clearly showed that one opioid was more effective than another. Overall, findings indicated that parenteral opioids provided some pain relief and moderate satisfaction with analgesia in labour. Opioid drugs were associated with maternal nausea, vomiting and drowsiness, although different opioid drugs were associated with different adverse effects. There was no clear evidence of adverse effects of opioids on the newborn. We did not have sufficient evidence to assess which opioid drug provided the best pain relief with the least adverse effects.

AUTHORS' CONCLUSIONS

Though most evidence is of low- or very-low quality, for healthy women with an uncomplicated pregnancy who are giving birth at 37 to 42 weeks, parenteral opioids appear to provide some relief from pain in labour but are associated with drowsiness, nausea, and vomiting in the woman. Effects on the newborn are unclear. Maternal satisfaction with opioid analgesia was largely unreported. The review needs to be examined alongside related Cochrane reviews. More research is needed to determine which analgesic intervention is most effective, and provides greatest satisfaction to women with acceptable adverse effects for mothers and their newborn.

Pre-emptive ketorolac for prevention of intraoperative shoulder pain in patients undergoing cesarean section: A double blind randomized clinical trial

BACKGROUND

Shoulder pain is a commonly observed but mostly neglected consequence of cesarean section and little is known as well as explored about intraoperative shoulder pain. We conducted this randomized prospective double-blinded study to evaluate the efficacy of ketorolac in reducing the incidence and severity of intraoperative shoulder pain in patients undergoing cesarean section.

METHODS

Two hundred ASA I and II patients scheduled to undergo elective cesarean section under spinal anesthesia were randomized to receive either intravenous ketorolac 30 mg (ketorolac group) or normal saline (control group). The primary outcome was the incidence of intraoperative shoulder pain. Secondary outcomes were severity of intraoperative shoulder pain, amount of intraoperative blood loss, incidence of hypotension, bradycardia and request for intraoperative rescue analgesia.

RESULTS

The incidence of intraoperative shoulder pain in the control group was significantly higher than the ketorolac group (P = 0.003). Severity of shoulder pain and requests for intraoperative analgesia was significantly higher in the control group (P = 0.012, P = 0.006 respectively). Patients in the Ketorolac group experienced significantly higher incidences of bradycardia (P = 0.037).

CONCLUSION

30 mg ketorolac administered intravenously just before the operation could decrease incidence and severity of intraoperative shoulder pain in patients undergoing cesarean section.

CLINICAL TRIAL REGISTRATION

ClinicalTrial.gov (Registration number: NCT02380898, first registered in 01/03/2015).

Nonsteroidal anti-inflammatory drugs during pregnancy and the initiation of lactation

Nonsteroidal anti-inflammatory drugs (NSAIDs) and aspirin, which are available as "over-the counter" medications in most countries, are widely used by both pregnant and lactating women. They are popular non-opioid analgesics for the treatment of pain after vaginal and operative delivery. In addition, NSAIDs are used for tocolysis in premature labor, and low-dose aspirin has a role in the prevention of preeclampsia and recurrent miscarriage in antiphospholipid syndrome. NSAIDs and aspirin may affect fertility and increase the risk of early pregnancy loss. In the second trimester their use is considered reasonably safe, but has been associated with fetal cryptorchism. In the third trimester, NSAIDs and aspirin are usually avoided because of significant fetal risks such as renal injury, oligohydramnios, constriction of the ductus arteriosus (with potential for persistent pulmonary hypertension in the newborn), necrotizing enterocolitis, and intracranial hemorrhage. Maternal administration or ingestion of most NSAIDs results in low infant exposure via breastmilk, such that both cyclooxygenase-1 and cyclooxygenase-2 inhibitors are generally considered safe, and preferable to aspirin, when breastfeeding.

Non-opioid drugs for pain management in labour

BACKGROUND

Labour is a normal physiological process, but is usually associated with pain and discomfort. Numerous methods are used to relieve labour pain. These include pharmacological (e.g. epidural, opioids, inhaled analgesia) and non-pharmacological (e.g. hypnosis, acupuncture) methods of pain management. Non-opioid drugs are a pharmacological method used to control mild to moderate pain.

OBJECTIVES

To summarise the evidence regarding the effects and safety of the use of non-opioid drugs to relieve pain in labour.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (15 February 2012).

SELECTION CRITERIA

Randomised controlled trials (RCTs) using non-opioid drugs (non-steroidal anti-inflammatory drugs (NSAIDs); paracetamol; antispasmodics; sedatives and antihistamines) in comparison with placebo or standard care; different forms of non-opioid drugs (e.g. sedatives versus antihistamines); or different interventions (e.g. non-opioids versus opioids) for women in labour. Quasi-RCTs and trials using a cross-over design were not included. Cluster-randomised RCTs were eligible for inclusion but none were identified for inclusion.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed for inclusion all studies identified by the search strategy, carried out data extraction and assessed risk of bias. We resolved any disagreement through discussion with a third author. Data were checked for accuracy.

MAIN RESULTS

Nineteen studies randomising a total of 2863 women were included in this review. There were three main comparison groups: 15 studies compared non-opioid drugs with placebo or no treatment (2133 women); three studies compared non-opioid drugs with opioids (563 women); and three studies compared one type of non-opioid drug with a different type or dose of non-opioid drug (590 women). Some of the studies included three or more groups and so have been put in more than one comparison. Overall, there was little difference between groups for most of the comparisons. Any differences observed for outcomes were mainly limited to one or two studies. Non-opioid drugs (sedatives) were found to offer better pain relief (mean difference (MD) -22.00; 95% confidence interval (CI) -35.86 to -8.14, one trial, 50 women), better satisfaction with pain relief (sedatives and antihistamines) (risk ratio (RR) 1.59; 95% CI 1.15 to 2.21, two trials, 204 women; RR 1.80; 95% CI 1.16 to 2.79, one trial, 223 women) and better satisfaction with the childbirth experience (RR 2.16; 95% CI 1.34 to 3.47, one trial, 40 women) when compared with placebo or no treatment. However, women having non-opioid drugs (NSAIDs or antihistamines) were less likely to be satisfied with pain relief compared with women having opioids (RR 0.50; 95% CI 0.27 to 0.94, one trial, 76 women; RR 0.73; 95% CI 0.54 to 0.98, one trial, 223 women). Women receiving the antihistamine hydroxyzine were more likely to express satisfaction with pain relief compared with the antihistamine promethazine (RR 1.21; 95% CI 1.02 to 1.43, one trial, 289 women). Women receiving sedatives were more likely to express satisfaction with pain relief compared with antihistamines (RR 1.52; 95% CI 1.06 to 2.17, one study, 157 women). The majority of studies were conducted over 30 years ago. The studies were at unclear risk of bias for most of the quality domains.Opioids appear to be superior to non-opioids in satisfaction with pain relief, while non-opioids appear to be superior to placebo for pain relief and satisfaction with the childbirth experience. There were little data and no evidence of a significant difference for any of the comparisons of non-opioids for safety outcomes. 

AUTHORS' CONCLUSIONS

Overall, the findings of this review demonstrated insufficient evidence to support a role for non-opioid drugs on their own to manage pain during labour.

Parenteral opioids for maternal pain relief in labour

BACKGROUND

Parenteral opioids are used for pain relief in labour in many countries throughout the world.

OBJECTIVES

To assess the acceptability, effectiveness and safety of different types, doses and modes of administration of parenteral opioids given to women in labour.

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (January 2010) and reference lists of retrieved studies.

SELECTION CRITERIA

We included randomised controlled trials examining the use of intramuscular or intravenous opioids (including patient controlled analgesia) for women in labour. We looked at studies comparing an opioid with placebo or another opioid.

DATA COLLECTION AND ANALYSIS

At least two review authors independently assessed study eligibility, collected data and assessed risk of bias.

MAIN RESULTS

We included 54 studies involving more than 7000 women that compared an opioid with placebo or another opioid administered intramuscularly or intravenously. The 54 studies reported on 27 different comparisons, and for many outcomes only one study contributed data. Overall the evidence was of poor quality regarding the analgesic effect of opioids, satisfaction with analgesia, adverse effects and harm to women and babies. There were few statistically significant results. Many of the studies had small sample sizes, and low statistical power. Overall, findings indicated that parenteral opioids provided some pain relief and moderate satisfaction with analgesia in labour, although up to two-thirds of women who received opioids reported moderate or severe pain and/or poor or moderate pain relief one or two hours after administration. Opioid drugs were associated with maternal nausea, vomiting and drowsiness, although different opioid drugs were associated with different adverse effects. There was no clear evidence of adverse effects of opioids on the newborn. We did not have sufficient evidence to assess which opioid drug provided the best pain relief with the least adverse effects.

AUTHORS' CONCLUSIONS

Parenteral opioids provide some relief from pain in labour but are associated with adverse effects. Maternal satisfaction with opioid analgesia was largely unreported but appeared moderate at best. We did not examine the effectiveness and safety of parenteral opioids compared with other methods of pain relief in labour and this review needs to be examined alongside related Cochrane reviews. More research is needed to determine which analgesic intervention is most effective, and provides greatest satisfaction to women with acceptable adverse events for mothers and their newborns.

WITHDRAWN: Types of intra-muscular opioids for maternal pain relief in labour

BACKGROUND

Pethidine is the most widely used intra-muscular opioid for the relief of labour pain. However concerns have been raised about its effectiveness and the possibility of depressing respiration in newborns.

OBJECTIVES

The objective of this review was to assess the effects of different opioids (and different doses of the same opioid) administered intra-muscularly in labour.

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group trials register, the Cochrane Controlled Trials Register (Cochrane Library, issue 4, 1997) and reference lists of articles.

SELECTION CRITERIA

Randomised trials comparing the effects of different currently used opioids (and different doses of the same opioid) administered intramuscularly in labour for women who request systemic analgesia.

DATA COLLECTION AND ANALYSIS

Two reviewers assessed trial quality and extracted data. Analysis was based on the groups as randomly allocated.

MAIN RESULTS

Sixteen trials were included. There were problems with methodological quality of some of the trials, and lack of consistency in the way various outcomes were reported. There was no evidence of a difference between pethidine and tramadol in terms of pain relief, interval to delivery, or instrumental or operative delivery. There appeared to be more adverse effects such as nausea and vomiting and drowsiness with pethidine. Maternal pain relief seemed almost identical between the meptazinol and pethidine groups, whether assessed as maternal satisfaction with pain relief, visual analogue scales, or use of other pain relief, but meptazinol gave rise to slightly more side effects. Maternal satisfaction with pain relief appeared similar for pentazocine and pethidine, with more frequent nausea and vomiting with pethidine.

AUTHORS' CONCLUSIONS

There is not enough evidence to evaluate the comparative efficacy and safety of the various opioids used for analgesia in labour.

Types of intra-muscular opioids for maternal pain relief in labour

BACKGROUND

Pethidine is the most widely used intra-muscular opioid for the relief of labour pain. However concerns have been raised about its effectiveness and the possibility of depressing respiration in newborns.

OBJECTIVES

The objective of this review was to assess the effects of different opioids (and different doses of the same opioid) administered intra-muscularly in labour.

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group trials register, the Cochrane Controlled Trials Register (Cochrane Library, issue 4, 1997) and reference lists of articles.

SELECTION CRITERIA

Randomised trials comparing the effects of different currently used opioids (and different doses of the same opioid) administered intramuscularly in labour for women who request systemic analgesia.

DATA COLLECTION AND ANALYSIS

Two reviewers assessed trial quality and extracted data. Analysis was based on the groups as randomly allocated.

MAIN RESULTS

Sixteen trials were included. There were problems with methodological quality of some of the trials, and lack of consistency in the way various outcomes were reported. There was no evidence of a difference between pethidine and tramadol in terms of pain relief, interval to delivery, or instrumental or operative delivery. There appeared to be more adverse effects such as nausea and vomiting and drowsiness with pethidine. Maternal pain relief seemed almost identical between the meptazinol and pethidine groups, whether assessed as maternal satisfaction with pain relief, visual analogue scales, or use of other pain relief, but meptazinol gave rise to slightly more side effects. Maternal satisfaction with pain relief appeared similar for pentazocine and pethidine, with more frequent nausea and vomiting with pethidine.

REVIEWER'S CONCLUSIONS

There is not enough evidence to evaluate the comparative efficacy and safety of the various opioids used for analgesia in labour.

Efficacy of ketorolac tromethamine versus meperidine in the ED treatment of acute renal colic

To compare the efficacy of intramuscular ketorolac and meperidine in the emergency department (ED) treatment of renal colic, a prospective, controlled, randomized, double-blind trial was conducted in an academic ED with 76,000 annual visits. Participants were volunteer ED patients with a diagnosis of ureterolithiasis confirmed by intravenous pyelogram. Subjects were randomized 1:1 to receive a single intramuscular injection of either 60 mg ketorolac or 100 to 150 mg meperidine, based on weight. Of the 70 patients completing the trial, 33 received ketorolac and 37 received meperidine. Demographic characteristics and baseline pain scores of both groups were comparable (P = NS, Mann Whitney U). Ketorolac was significantly (P < .05) more effective than meperidine in reducing renal colic at 40, 60, and 90 minutes as measured on a 10-cm visual analogue scale. Similar proportions of patients in each group were given rescue analgesia and admitted. Of patients who were discharged home without rescue, those treated with ketorolac left the ED significantly earlier than those treated with meperidine (3.46 v 4.33 h, P < .05). These results show that intramuscular ketorolac as a single agent for renal colic is more effective than meperidine and promotes earlier discharge of renal colic patients from the ED.

Parturients' assessment of water blocks, pethidine, nitrous oxide, paracervical and epidural blocks in labour

This prospective study evaluated the extent to which the analgesic procedures available resulted in efficient pain relief in 833 Finnish parturients. Their pain ratings were recorded according to their own assessment of pain intensity during labour before and after pain management and according to their total pain experience recalled on the third day after delivery. Only regional blocks significantly diminished pain scores during labour and a striking decrease in pain level (P < 0.0001) was maintained until the second stage by epidural analgesia (EDA) alone. The EDA-group consisted mainly of the primiparous (71%) with induced (17%) and most painful deliveries. After delivery 60% of parturients in this group recalled labour pain as being very severe or intolerable. This was partly due to delays in receiving epidural blockade and partly due to the parturient's reticence in requesting analgesia. Pain relief was rated as excellent or good by 94% of the EDA group but by only 50% of the remaining patients.

Analgesia after caesarean section with intramuscular ketorolac or pethidine

We compared, in a double-blind randomised study, intramuscular ketorolac 30 mg (n = 49) and intramuscular pethidine 75 mg (n = 51) for analgesia after elective caesarean section under general anaesthesia. Anaesthesia was induced with thiopentone and suxamethonium and maintained with atracurium, nitrous oxide and isoflurane. Intravenous fentanyl 100 micrograms was given after delivery of the neonate. In the recovery ward, patients who requested analgesia were allocated randomly to receive ketorolac 30 mg or pethidine 75 mg intramuscularly. Analgesia was assessed at intervals up to six hours, using a visual analogue scale and a four-point verbal scale, while duration of analgesia was taken as the time until the patient requested additional analgesia. There was no difference in the duration of analgesia between groups (Mann-Whitney test P = 0.27, Mantel-Haentszel test P = 0.17). Twenty-six patients in the ketorolac group and 17 patients in the pethidine group requested further analgesia by 90 minutes. However, four patients in the ketorolac group and six patients in the pethidine group requested no further analgesia within 24 hours. Pain VAS and overall assessment of analgesia was similar between groups, although more side-effects (nausea, dizziness) were noted in the pethidine group. Ketorolac 30 mg and pethidine 75 mg provided similar but variable quality of analgesia after caesarean section.