Review of: Safdar B, Degutis LC, Landry K, et al: “Intravenous morphine plus ketorolac is superior to either drug alone for treatment of acute renal colic.” Annals of Emergency Medicine. 48:173-181, 2006.
The authors compared the pain relief of intravenous morphine to intravenous ketorolac (Toradol ) and to a combination of the two. One-hundred-fifty-eight patients with signs and symptoms consistent with renal colic were randomized to receive either 5 mg of morphine, 15 mg of ketoroac, or a combination of 5 mg morphine and 15 mg ketorolac. After 20 minutes, their pain level was reassessed and they received a repeat dose of the same drug. After 40 minutes, their pain was assessed and they were provided additional doses of morphine to get their pain level below 3 on a visual analog score.
They found that there was no significant difference between morphine alone and ketorolac alone in pain relief as gauged by the need to administer additional (rescue) doses of morphine. However, the combination of morphine and ketorolac resulted in significantly greater pain relief than either drug alone. Furthermore, the combination of morphine and ketorolac resulted in fewer adverse side effects, primarily nausea and vomiting.
The issue of pain management both in and out of the hospital has become a major indicator for quality of patient care. There is nothing more frustrating than transporting a patient suffering agonizing pain in the ambulance and having nothing to give them to ease their misery. There continues to be controversy regarding the liberalization of the use of prehospital analgesia and hopefully studies such as this can be used to show the benefit of its use.
With proper training and education, it is reasonable to expect paramedics to recognize a patient with renal colic. This study showed that the combination of both an opiate analgesic with a non-steroidal anti-inflammatory resulted in significantly greater pain reduction as well as few adverse side effects. For medical directors who continue to be hesitant about the use of morphine by EMS in these circumstances, this paper supports the administration of ketorolac alone owing to its equivalency in providing pain relief for renal colic.
However, as the authors point out in this paper, the doses of both morphine and ketorolac were not optimal. Initial dosages of morphine should be 0.1 mg/kg and therefore adjusted based on weight. In this study, some patients may have received too much or too little since the dose was not weight based. This may have contributed to the incidence of adverse effects, though this was not analyzed by the authors. Additionally, while the PDR recommends an initial dose of 15 mg of ketorolac, 30 mg is the customary dose in most emergency departments. Had the patients been given weight-based doses of morphine and the higher dose of ketorolac, the results may have been different.
Finally, the authors did not report the frequency of anti-emetic medication administration. Nausea is a frequent symptom of renal colic and is commonly treated with medication along with analgesics. Some studies have reported that anti-emetics alone can produce significant analgesia and therefore their effect in this study is unknown.
Regardless, studies such as this continue to highlight the importance of treating our patients pain with the most appropriate combination of medications to produce the highest degree of pain relief with the least amount of adverse side effects.