A two-dose epidural morphine regimen for cesarean section patients: therapeutic efficacy

Dexamethasone for preventing nausea and vomiting associated with epidural morphine: a dose-ranging study

We conducted a dose-ranging study of dexamethasone for preventing nausea and vomiting within the first 24 h after the administration of epidural morphine. Two hundred twenty-five women (n = 45 in each of the five groups) undergoing simple abdominal total hysterectomy under epidural anesthesia were enrolled in this randomized, double-blind, placebo-controlled study. When the incision closure was completed, patients received IV dexamethasone, 10 mg, 5 mg, or 2.5 mg; IV droperidol 1.25 mg; or saline 2 mL. All patients received epidural morphine 3 mg for postoperative analgesia. We found that patients who received dexamethasone 5 mg or 10 mg or droperidol 1.25 mg were significantly different from those who received saline alone in the following variables: the total incidence of nausea and vomiting, the incidence of more than four vomiting episodes, the number of patients requiring rescue antiemetics, the total number of patients with no vomiting and/or no antiemetic medication (P < 0.05 to P < 0.01). The differences among dexamethasone 10 mg and 5 mg and droperidol 1.25 mg were not significant. Dexamethasone 2.5 mg was ineffective. In conclusion, because dexamethasone 5 mg was as effective as 10 mg as an antiemetic, we recommend the smaller dose for preventing nausea and vomiting associated with epidural morphine.

IMPLICATIONS

We conducted a dose-ranging study of dexamethasone for preventing nausea and vomiting within the first 24 h after the administration of epidural morphine. We found that dexamethasone 5 mg was as effective as 10 mg. We recommend the smaller dose for this purpose.

Dexamethasone for prophylaxis of nausea and vomiting after epidural morphine for post-Caesarean section analgesia: comparison of droperidol and saline

We have evaluated the prophylactic effect of i.v. dexamethasone 8 mg in preventing nausea and vomiting during epidural morphine for post-Caesarean section analgesia. Droperidol 1.25 mg and saline served as the control. We studied 120 parturients (n=40 in each group) receiving epidural morphine for post-Caesarean section analgesia, in a randomized, double-blind, placebo-controlled study. All parturients received epidural morphine 3 mg. Both dexamethasone and droperidol significantly decreased the total incidence of nausea and vomiting compared with saline, with incidences of 18, 21 and 51% for the three treatments respectively (P<0.01 and P<0.05 respectively). Parturients who received droperidol reported a more frequent incidence of restlessness (16%) than those who received dexamethasone (P<0.05).

Droperidol and the side effects of epidural morphine after cesarean section

Epidural morphine produces analgesia with a high incidence of side effects that include pruritus, nausea, and vomiting. This study investigated whether epidural or i.v. droperidol could alleviate these symptoms. In a prospective, double-blind, randomized, controlled trial, 97 pregnant women undergoing cesarean section were randomly assigned to three groups. All received standard continuous epidural anesthesia. After delivery, each received 5 mg of epidural morphine with either no droperidol injection, 2.5 mg of epidural droperidol, or 2.5 mg of i.v. droperidol. The incidence, onset, duration, and severity of pruritus; the onset and severity of pain; and satisfaction were similar for each group, but the incidence and severity of nausea and vomiting was lower in the group that received i.v. droperidol (P < 0.01). Sedation was minimal throughout the study. Thus, epidural droperidol failed to alleviate the side effects caused by epidural morphine, but i.v.droperidol reduced both the incidence and severity of nausea and vomiting. These results suggest that droperidol acts systemically to counter the effects of epidural morphine but that it is not entirely effective.

IMPLICATIONS

A single dose of epidural morphine provides long-lasting pain relief for women who have undergone cesarean section, but it has some troublesome side effects (itching, nausea, vomiting). We performed a prospective, randomized, controlled trial in 97 such women to study whether droperidol could reduce these side effects. We found that i.v. droperidol reduced nausea and vomiting but did not prevent itching, and that epidural droperidol failed to prevent all side effects.

2-Chloroprocaine antagonism of epidural morphine analgesia

BACKGROUND

2-Chloroprocaine (2-CP) used for lumbar epidural anesthesia (LEA) reportedly decreases the efficacy of epidural morphine (EM) administered for post-cesarean section (CS) analgesia. The amount of supplemental i.v. morphine self-administered by the patient via the patient-controlled analgesia device (PCA) is used to study the interaction between EM and 2-CP.

METHODS

Forty-two patients scheduled for elective CS were randomly divided into 3 equal groups, and received 2-CP, 2-CP + epinephrine (Epi, 5 micrograms.ml-1) or 2% lidocaine (Lido) with Epi for LEA. All patients received 5 mg EM and i.v. PCA morphine for postoperative pain. Cumulative amount of i.v. morphine used in the first 24 hours as well as the amount of the drug used during each 2-h period were noted. Nonparametric analysis of variance and Chi-squared analysis were used for statistical comparisons.

RESULTS

The mean cumulative 24-h i.v. PCA morphine requirement in the 2-CP, 2-CP+Epi and Lido+Epi groups respectively was 20.5 +/- 24, 33.1.5 +/- 27 and 4.07 +/- (mean +/- SD). The Lido + Epi group used significantly less morphine (P = 0.01) compared to either of the 2-CP groups with no significant difference between the 2-CP groups. The maximum i.v. PCA morphine use occurred in the first 4 hours following surgery in all three groups.

CONCLUSION

Analgesic efficacy of EM is decreased when 2-CP is used for LEA compared to when Lido + Epi is used.

Epidural analgesia with 4 mg of morphine following caesarean section: effect of injected volume

The efficacy and side effects of epidural bolus injection of 4 mg of morphine in a volume of 2 ml, 10 ml, or 20 ml (groups I, II and III) for postoperative analgesia after caesarean section (60 patients) were evaluated. All patients had epidural anaesthesia established up to T4 level with 0.5% bupivacaine 18-20 ml, supplemented with 2% lidocaine with adrenaline, when necessary. Morphine 4 mg in either of the three volumes was injected through the epidural catheter in random order after delivery of the baby. Six patients in each group reported no pain during the 24-h follow-up period. No additional pain medication during the 24 h after surgery was required in 11, 14 and 10 patients in groups I, II and III, respectively. Most of the others managed with the addition of a single dose of rectal ketoprofen. There were no differences in analgesic therapy between the groups. Pruritus was the most common adverse effect (18/20, 19/20 and 18/20 in groups I, II and III, respectively). 10/20, 12/20 and 14/20 (N.S.) patients had nausea and vomiting in groups I, II and III, respectively. Metoclopramide, prescribed for persistent nausea, was given to 4/20 patients in group I, 6/20 patients in group II and 9/20 patients in group III (N.S.). After removal of the urinary catheter 7/20 patient in group III required carbachol for urinary retention compared to 3/20 and 4/20 patients in groups I and II (N.S.).(ABSTRACT TRUNCATED AT 250 WORDS)

A two-dose epidural morphine regimen in cesarean section patients: pharmacokinetic profile

The maternal pharmacokinetics, metabolism of, and possible neonatal transmission of epidural morphine in cesarean section patients were investigated. Maternal plasma, breast milk, and maternal and neonatal urine concentrations of unconjugated and conjugated (UM and CM) morphine were measured in patients given two 5-mg doses of epidural morphine for post-cesarean section analgesia. The first dose was administered after delivery and the second dose 24 h later. Maternal venous blood samples (n = 10) were collected at times 0, 0.25, 0.5, 1, 2, 3, 4, 6, 12, and 24 h after each dose, and maternal urine was collected for three consecutive 24-h periods (n = 30). Maternal breast milk (n = 30), and neonatal urine samples (n = 20) were also collected. Serum, urine, and breast milk UM and CM levels were measured using radioimmunoassay. Pharmacokinetic values were calculated using noncompartmental analysis. The results were expressed as mean +/- 1 s.e. mean and analyzed using repeated measures analysis of variance and the paired t-test. Maternal serum UM remained 40-50% higher, and CM 50-100% higher in the first hour following dose 2 than the respective values after dose 1 (P < 0.05). Values for AUC, AUMC, T1/2, and MRT increased 28%, 83%, 35% and 36%, respectively, with the second dose (P < 0.05), while CI decreased 19% (P < 0.05) with no significant difference in Vss. Total urinary excretion of morphine decreased significantly from 1.98 +/- 0.15 mg on day 1 to 1.6 +/- 0.2 mg and 0.19 +/- 0.002 mg on days 2 and 3, respectively (P < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)