english.prescrire.org > Spotlight > Archives : 2009 > Renal colic in adults: NSAIDs and morphine are effective for pain relief

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Abstract

Renal colic is an acute syndrome involving unilateral flank pain, linked to an obstruction in the upper urinary tract. The pain is often intense. After having considered other diagnoses and checked for signs of complication (fever, oligoanuria), the first step is to control the pain.

Which non-invasive treatments have a positive risk-benefit balance in relieving this type of pain? To answer this question, we reviewed the available evidence, based on the standard Prescrire methodology.

According to a meta-analysis of 20 trials, nonsteroidal anti-inflammatory drugs (NSAIDs) and strong opioid analgesics have comparable efficacy. The most widely studied NSAID is diclofenac, given intramuscularly at a dose of 50 mg or 75 mg. Pethidine is the best-assessed strong opioid, given intramuscularly at a dose of 50 mg to 100 mg, which corresponds to about 5 mg to 10 mg of morphine. Morphine is given intravenously; subcutaneous administration is an alternative although it has not been evaluated in renal colic.

In clinical trials, NSAIDs were associated with fewer adverse effects than opioids, which cause vomiting in about 20% of patients (versus about 6% with an NSAID).

NSAIDs expose patients to a risk of functional renal impairment, especially patients with heart failure, renal artery stenosis, dehydration, renal impairment or ongoing treatment with a nephrotoxic drug, and the very elderly. NSAIDs should never be used during pregnancy.

According to one trial in 130 patients, the analgesic effect of the morphine and NSAID combination was greater than either agent used alone, in about 10% of patients.

Paracetamol has not been evaluated in comparative trials of renal colic, even for moderate pain.

Scopolamine is the only antispasmodic to have been evaluated in a comparative trial. Adding scopolamine to morphine did not seem to provide additional efficacy.

Other drugs, which have not been adequately tested as of early 2009, have no documented benefit in the treatment of the pain associated with renal colic: tamsulosin, nifedipine, desmopressin.

Among the non-drug measures tested, local active warming, taking care to avoid burns, was effective against pain according to one trial: pain was reduced by at least 50% using a device delivering 42°C to the abdomen or lower back.

In pregnant women, morphine carries a lower risk of adverse effects than NSAIDs.

In practice, the treatment of renal colic is mainly based on taking an NSAID, or morphine when the NSAID does not adequately control the pain or when it is better to avoid using NSAIDs.

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