NSAID alleviates pain of PNL in select patients

Cleveland-Intravenous ketorolac tromethamine is safe and appears to be effective at alleviating pain following percutaneous nephrolithotomy (PNL) procedures in properly selected patients, according to a study from the Methodist Hospital Institute for Kidney Stone Disease and Indiana University School of Medicine, Indianapolis.

"The ideal postoperative pain protocol for patients undergoing percutaneous nephrolithotomy has not yet been designed," said Nicole L. Miller, MD, a fellow in endourology at the hospital working with James E. Lingeman, MD, and colleagues. "Our thoughts were to investigate this in percutaneous nephrolithotomy patients because it has been shown to work well in patients with acute renal colic. IV ketorolac has been well studied in a variety of procedures. It has been shown to be very effective in cancer patients as an adjunct to standard pain medication regimens."

She noted that one of the advantages of establishing ketorolac, a nonsteroidal anti-inflammatory drug, as an analgesic agent in PNL is that it allows the cognitive impairments seen with opioids to be avoided. This can be a significant consideration in older patients.

The ketorolac patients were given a bolus of the agent postoperatively (30 mg) followed by continuous IV infusion (3.6 mg/hour). The investigators were primarily concerned with biologic responses. They compared the changes in creatinine and hemoglobin in the ketorolac patients with those receiving the narcotics alone.

The ketorolac patients had a lower preoperative creatinine compared with patients who received the narcotic alone (1.03 mg/dL vs. 1.33 mg/dL). This reflected a selection bias in those patients excluded from ketorolac owing to contraindications, said Dr. Miller. Both groups showed a rise in postoperative creatinine. The ketorolac patients showed a 0.19 mg/dL rise compared with the narcotic group, which showed a 0.12 mg/dL rise. The groups also showed a drop in hemoglobin. Hemoglobin for the ketorolac group fell 2.3 gm/dL, and the group receiving narcotics saw a 2.0 gm/dL drop.

Careful patient selection

"The drug has been shown in the literature to be safe in the treatment of a number of medical conditions. The next step is to see if this is a superior pain regimen compared to what is being used. We have no data to support observations [on comparative pain relief] right now," Dr. Miller told Urology Times.

"However, patients must be properly selected," she added. "The company says the drug should be used with caution in patients with impaired renal function, but it is not truly contraindicated. When they did post-marketing surveillance, they found that complications increased as the dose increased and as age increased or when treatment extended beyond 5 days."

The agent was used routinely at Methodist Hospital in all patients with normal renal function, according to Dr. Miller. Only the elderly, patients with poor renal function, and those with an allergy to NSAIDs were excluded. These patients were usually treated with narcotics.

The researchers noted that ketorolac has been on the market for a number of years (parenteral use was approved in 1989), but that there was relatively scant information on its use in this particular setting.

"I started to use the drug [for PNL] about 3 years ago. I think the first report of its application was in the late 1990s or early 2000, and that was a case report. There are studies of the agent, but the majority are in anesthesia journals," Dr. Miller said.