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360 Renal colic
scores. 3 The Cochrane review also reported that those receiving NSAIDs are
less likely to require rescue medication and less likely to vomit than those
receiving opioids. However, the review did not address GI bleeding or renal
impairment, which constitute the two most serious NSAID-associated
adverse events. Furthermore, since meperidine was the opioid used in
most of the reviewed studies, it is possible that some of the effects attributed
to opioids might, in fact, be less likely in patients receiving morphine or
hydromorphone.
An RCT published after that Cochrane review adds important data to the
consideration of RC treatment in the ED. A comparison of morphine (5 mg
IV, repeated after 20 min), ketorolac (15 mg IV, repeated after 20 min), and a
combination of both, found that dual therapy provides significantly better
pain relief than either drug alone. The combination of morphine plus ketorolac
was also associated with a decreased requirement for rescue analgesia. 4
In North America, the major advantage of ketorolac is its availability for
parenteral delivery. This advantage is important, since many patients with
RC have associated nausea and vomiting and cannot tolerate oral medication.
There is also a role for ketorolac monotherapy for patients in whom
opioids are contraindicated. The NSAID metamizole is found in Cochrane
review to be effective when given IV, but this agent’s association with blood
dyscrasias renders it unavailable in some countries (e.g. USA, UK) and its use
is not recommended. 5
Currently developing evidence suggests that the most effective pain medications
for RC might prove to be neither NSAIDs nor opioids. Instead, the
optimal approach to RC relief may entail administration of medications that
relieve symptoms by inducing rapid stone passage. A systematic review of
RCTs evaluating calcium channel blockers or alpha-adrenergic blockers for
RC found both effectively relieved pain and facilitated stone passage in patients
amenable to conservative management. 6 Although the results are promising
for ED patients, acute care use of this therapeutic approach requires tailoring
therapy to stone size and location. In the future, ED provider understanding of
this information may broaden acute care therapeutic options for RC.
The fact that ureteral smooth muscle spasm is a primary mediator of RC
pain has prompted investigations of antispasmodic (antimuscarinic) agents