Determination of ED50 of hydromorphone for postoperative analgesia following cesarean delivery

The 50% effective dose of hydromorphone and morphine for epidural analgesia in the hemorrhoidectomy: a double-blind, sequential dose-finding study

BACKGROUND

Although previous studies have showed that epidural morphine can be used as a complement to local anesthetics for analgesia after postcesarean delivery under spinal anesthesia, there is little known about the analgesic dosage of epidural morphine and hydromorphone for hemorrhoidectomy. Therefore, we conducted this study to examine the potency ratio of hydromorphone to epidural morphine as well as effective analgesic dose for 50% patients (ED50) undergoing elective hemorrhoidectomy.

METHODS

80 patients under elective hemorrhoidectomy with combined spinal and epidural anesthesia(CSEA) in department of anesthesia, Dongguan Tungwah hospital. To assess the ED50, patients were treated with epidural morphine or epidural hydromorphone randomly using a biased coin method-determined dose with a sequential allocation procedure. Following surgery, standardized multimodal analgesia was administered to all patients. A pain response score of ≤ 3 (on a scale of 0-10) was determined to be the effective dose after 24 h following CSEA. The ED50 in both groups were determined using the probit regression and isotonic regression method. We also measured pain intensity by patient interview using a 10 point verbal numeric rating scale prospectively at 6, 12 and 24 h after CSEA, and adverse effects were also noted.

RESULTS

The ED50 was 0.350 mg (95% CI, 0.259-0.376 mg) in hydromorphone group and 1.129 mg (95% CI, 0.903-1.187 mg) in morphine group, respectively, estimated by isotonic regression method. Regression analysis with the probit, the ED50 of epidural hydromorphone was 0.366 mg (95% CI, 0.276-0.388 mg) and epidural morphine was 1.138 mg (95% CI, 0.910-1.201 mg). Exploratory findings showed that there was no difference between the most frequent dosages of epidural hydromorphone or epidural morphine in the occurrence of nausea, vomiting and pruritus. When administered with epidural opioids at ED50 doses or higher, 97.5% (39/40) of epidural morphine patients and 97.5% (39/40) epidural hydromorphone of patients were satisfied with their analgesia.

CONCLUSION

Effective hemorrhoidectomy analgesia requires a 3:1 ratio of epidural morphine to epidural hydromorphone. Both drugs provide excellent patient satisfaction.

Intrathecal Morphine versus Intrathecal Hydromorphone for Analgesia after Cesarean Delivery: A Randomized Clinical Trial

BACKGROUND

Intrathecal opioids are routinely administered during spinal anesthesia for postcesarean analgesia. The effectiveness of intrathecal morphine for postcesarean analgesia is well established, and the use of intrathecal hydromorphone is growing. No prospective studies have compared the effectiveness of equipotent doses of intrathecal morphine versus intrathecal hydromorphone as part of a multimodal analgesic regimen for postcesarean analgesia. The authors hypothesized that intrathecal morphine would result in superior analgesia compared with intrathecal hydromorphone 24 h after delivery.

METHODS

In this single-center, double-blinded, randomized trial, 138 parturients undergoing scheduled cesarean delivery were randomized to receive 150 µg of intrathecal morphine or 75 µg of intrathecal hydromorphone as part of a primary spinal anesthetic and multimodal analgesic regimen; 134 parturients were included in the analysis. The primary outcome was the numerical rating scale score for pain with movement 24 h after delivery. Static and dynamic pain scores, nausea, pruritus, degree of sedation, and patient satisfaction were assessed every 6 h for 36 h postpartum. Total opioid consumption was recorded.

RESULTS

There was no significant difference in pain scores with movement at 24 h (intrathecal hydromorphone median [25th, 75th] 4 [3, 5] and intrathecal morphine 3 [2, 4.5]) or at any time point (estimated difference, 0.5; 95% CI, 0 to 1; P = 0.139). Opioid received in the first 24 h did not differ between groups (median [25th, 75th] oral morphine milligram equivalents for intrathecal hydromorphone 30 [7.5, 45.06] vs. intrathecal morphine 22.5 [14.0, 37.5], P = 0.769). From Kaplan-Meier analysis, the median time to first opioid request was 5.4 h for hydromorphone and 12.1 h for morphine (log-rank test P = 0.200).

CONCLUSIONS

Although the hypothesis was that intrathecal morphine would provide superior analgesia to intrathecal hydromorphone, the results did not confirm this. At the doses studied, both intrathecal morphine and intrathecal hydromorphone provide effective postcesarean analgesia when combined with a multimodal analgesia regimen.

Determination of the ED50 and ED95 of intravenous bolus of norepinephrine for the treatment of hypotension during spinal anesthesia for cesarean delivery

Norepinephrine is considered as a potential alternative for blood pressure stabilization during spinal anesthesia for cesarean delivery, as it maintains a better maternal heart rate and cardiac output compared with phenylephrine. However, its use as a bolus dose for hypotension treatment remains largely unexplored. Therefore, the present study investigated the ED50 and ED95 of norepinephrine as a bolus for maternal hypotension during cesarean delivery. In the present prospective trial, 42 patients were enrolled for elective delivery under spinal anesthesia. The dose of norepinephrine was decided by the up-and-down sequential allocation method (UDM) with an initial dose of 0.075 µg/kg and a 0.025 µg/kg increment. The 42 patients received a bolus of norepinephrine when systolic blood pressure fell to <80% of baseline. The ED50 was calculated by the sequential method and the probit regression model. The ED95 was then calculated using the probit regression model. The ED50 of norepinephrine, which was determined by the UDM, was 0.067 µg/kg (95% CI, 0.056-0.081). The probit regression model calculated an ED50 of 0.072 µg/kg (95% CI, 0.056-0.088) and an ED95 of 0.121 µg/kg (95% CI, 0.1-0.207). In summary, the present results suggested the ED50 of a bolus norepinephrine for preventing hypotension in elective CD is 0.067 µg/kg (95% CI, 0.056-0.081), with an ED95 of 0.121 µg/kg (95% CI, 0.1-0.207).

Postoperative Analgesic Effects of Different Doses of Epidural Hydromorphone Coadministered with Ropivacaine after Cesarean Section: A Randomized Controlled Trial

Purpose

Single dose of epidural hydromorphone has been introduced to serve as an alternative method for postcesarean section analgesia. However, optimal dose of epidural hydromorphone remains unknown. Hence, we evaluated and compared the analgesic and adverse effects of postoperative different doses of epidural hydromorphone coadministered with ropivacaine after cesarean section.

Methods

Eighty term parturients with elective cesarean section under epidural anesthesia were allocated into four groups. Epidural analgesia was administered with an epidural bolus of either 0 mg (group H0), or 0.2 mg (group H1), or 0.4 mg (group H2), or 0.6 mg (group H3) hydromorphone coadministered with ropivacaine. The primary outcome was the visual analogue pain scores (VAPSs) and rescue opioid consumption (PCIA with sulfentanil) in 24 hours. Adverse effects such as respiratory depression, pruritus, nausea, and vomiting were recorded.

Results

The VAPSs of group H1 at 2, 4, 6, 12 h and 24 h after surgery was similar to group H0. The VAPSs of group H2 at 4 and 6 h postoperatively were significantly decreased when compared to group H0. But, the VAPSs of group H2 at 2, 12, and 24 h postoperatively were similar to those of group H0. The VAPSs of group H3 at 4, 6, 12 h, and 24 h after surgery were significantly decreased when compared to those of group H0. The total sulfentanil consumption in 24 hours was 90 ± 26 μg in group H0, 75 ± 29 μg in group H1, 54 ± 32 μg in group H2, and 15 ± 16 μg in group H0. Adverse effects were comparable in the four groups.

Conclusions

Epidural administration of 0.6 mg hydromorphone coadministered with ropivacaine after cesarean section provided satisfactory pain relief with less sulfentanil consumption. This trial is registered with ChiCTR-IPR-16010026.

Determination of ED50 and time to effectiveness for intrathecal hydromorphone in laboring patients using Dixon's up-and-down sequential allocation method

Background

With the increasing occurrence of drug shortages, understanding the pharmacokinetics of alternative intrathecal opioid administration has gained importance. In particular, additional data are needed to comprehensively evaluate the analgesic properties of intrathecal hydromorphone in the laboring patient. In a phase 2 clinical trial, we set out to determine the median effective dose (ED₅₀) and time to effectiveness for this drug in this population.

Methods

Using Dixon’s up-and-down sequential allocation method, twenty women presenting for labor analgesia were prospectively enrolled. A combined spinal-epidural technique was used to deliver the determined dose of intrathecal hydromorphone. Visual analog pain scores were obtained assessing peak pain scores during serial uterine contractions. Effective pain relief was defined as achieving a pain score of less than or equal to 3 out of 10. The dose was deemed to be ineffective if the patient failed to achieve this level of relief after 30 min.

Results

The ED₅₀ of hydromorphone in our population was 10.9 μg (95% confidence interval 5.6–16.2 μg). Amongst patients for whom the dose was effective, the median time to pain relief was 24 min. One patient experienced both nausea and pruritus. No other complications were noted.

Conclusion

Due to the prolonged time to onset, hydromorphone cannot be recommended in favor of substantively better alternatives such as sufentanil and fentanyl.

Trial registration

Clinicaltrials.gov registration number: NCT01598506.