In a prospective, randomized, double-blind study, Stanley et al. (A-30) examined the relative efficacy and side effects of morphine and pethidine, drugs commonly used for patient-controlled analgesia

(PCA). Subjects were 40 women, between the ages of 20 and 65 years, undergoing total abdominal hysterectomy. Patients were allocated randomly to receive morphine or pethidine by PCA. At the end of the study, subjects described their appreciation of nausea and vomiting, pain, and satisfaction by means of a three-point verbal scale. The results were as follows:

Satisfaction Drug Unhappy/

Miserable Moderately Happy Happy/

Delighted Total Pethidine 5 9 6 20 Morphine 9 9 2 20 Total 14 18 8 40 Pain Drug Unbearable/

Severe Moderate Slight/

None Total Pethidine 2 10 8 20 Morphine 2 8 10 20 Total 4 18 18 40 Nausea Drug Unbearable/

Severe Moderate Slight/

None Total Pethidine 5 9 6 20 Morphine 7 8 5 20 Total 12 17 11 40 Source: Data provided courtesy of Dr. Balraj L. Appadu.