Questions Raised About Around-the-Clock Analgesic Use

PONTE VEDRA BEACH, Florida—Cancer patients with bone metastases who received around-the-clock (ATC) analgesics took substantially more medication but did not have better pain relief than patients on as-needed (pro re nata, PRN) dosing regimens in a study reported by Christine Miaskowski, RN, PhD.

Dr. Miaskowski, chair, Department of Physiological Nursing, University of California, San Francisco, presented the results at the Oncology Nursing Society’s Sixth National Conference on Cancer Nursing Research

The researchers tracked the two groups for 5 weeks and found no differences in pain intensity measures. Yet patients in the ATC group had been prescribed an opioid analgesic dose five times higher on average than the dose given to the PRN group. The dose actually taken by the ATC patients was 12 times higher, she reported.

Describing ATC dosing of analgesics as a fundamental tenet of managing cancer-related pain, Dr. Miaskowski said that the surprising findings have significant clinical implications that merit further investigation.

"The variances were really big," she told ONI in a postconference interview. "We know very little about how providers make decisions about how to give analgesics to patients. We need to look at how patients take drugs, too. How do they report pain? We know virtually nothing about the decision-making process."

The researchers evaluated 74 ATC patients and 62 PRN patients, who were drawn from seven different cancer centers in Northern California. Patients had to have an ATC opioid prescription and take 80% or more of the ATC dose for 5 weeks to be classified in the ATC group.

The patients in the ATC group had lower Karnofsky Performance Scale scores than those in the PRN group, but otherwise showed no differences in demographic or disease characteristics.

The study is one of the longest to track cancer pain, according to Dr. Miaskowski. Four separate analyses found no divergence in pain intensity measures such as average, least, or worst pain scores, and number of hours a day in pain.

The researchers offered a number of potential explanations for future investigation, including the possibility that the current pain medication regimen is not effective for bone metastasis. A new kind of drug might be needed, she said. Also questioned was whether pain intensity scores are appropriate for analyzing analgesic regimens and whether analgesics are being titrated in response to the level of pain being reported by the patient.

Clinicians need to think more about assessing pain, titrating doses, and anticipating side effects, she suggested, calling side effects "the major reason patients don’t take their analgesics."