A comparison of papaveretum-promethazine with morphine-ondansetron for patient-controlled analgesia

Patient-controlled analgesia (PCA) with intravenous morphine is commonplace. Antiemetics are often added to reduce side-effects. In our institution an unusual combination of papaveretum-promethazine is in use.

We set out to compare this combination with a more commonly used one (morphine-ondansetron) by auditing the records of our pain-control team assessing analgesia and control of side-effects.

The records of two groups of 100 consecutive patients were studied. Pain scores were recorded 24 hours post-operatively on a scale of zero to ten. Also recorded were sedation scores, pruritus, emesis, and usage of breakthrough analgesia. The groups contained the work of a variety of anaesthetists and surgeons, though the majority were orthopaedic cases. All results were recorded by one pain-control nurse, using the same question, over a nine-month period.

Sedation scores were identical, while side-effects were few and similar in both groups. The use of breakthrough analgesia was also similar. However, the median pain-score of zero in the papaveretum group was significantly lower than that of two in the morphine group, (p < 0.001, Mann-Whitney U).

Papaveretum-promethazine appeared to be effective for PCA. This combination is also much less expensive than morphine-ondansetron. A previously described synergistic interaction between promethazine and opiates may be a factor in its success. Further evaluation of these drugs in PCA is warranted.