open access: As-Needed Morphine: Yes, but at What Dose and at What Interval?

..........Given the above-illustrated opinion conflicts, with a 10-fold variation in dose and a six-fold variation in timing interval, a search through published sources was conducted, mirroring a wide range of combinations regarding recommendations for both the PRN narcotic doses and the appropriate intervals at which they should be repeated in the event of continued pain. Data from 22 review articles and texts that review guidelines for the treatment of cancer pain, presented in Table 3, ^1-22 provided a 20-fold variation in recommended narcotic doses (1% to 20% of daily doses) along with scattered opinions, or no direction, regarding appropriate dose intervals for potential repeat doses...............

.............Specific guidelines for prescribing opioids are needed to allow practitioners to feel comfortable in administering these medications. These guidelines must include how to determine the appropriate dose for breakthrough pain, and the appropriate and safe interval that will allow for rapid pain relief, but maintain patient safety. On completion of this project, the 2004 National Comprehensive Cancer Network guidelines for cancer pain were found.²⁷ These guidelines come to similar conclusions that recommend the use of intravenous narcotic doses of 10% to 20% of the daily intravenous morphine equivalent and the use of repeat doses at 15-minute intervals, if pain is still present. The information from this project might be used to facilitate continuous-improvement projects at individual institutions. Such a project is in process locally. The incorporation of this new information regarding PRN narcotic use should better serve the needs of patients.

U.S. FDA: About the Center for Drug Evaluation and Research > Carboplatin dosing

Carboplatin dosing

"This communication is to inform members of the oncology community of recent changes in the measurement of serum creatinine which may have an impact on carboplatin dosing. Based on preliminary communications with the National Cancer Institute/Cancer Therapy Evaluation Program, a potential safety issue with carboplatin dosing has been identified. By the end of 2010, all clinical laboratories in the US will use the new standardized Isotope Dilution Mass Spectrometry (IDMS) method to measure serum creatinine. The IDMS method appears to underestimate serum creatinine values compared to older methods when the serum creatinine values are relatively low (e.g., ~0.7 mg/dL). Measurement of serum creatinine by the IDMS-method could result in an overestimation of the Glomerular Filtration Rate (GFR) in some patients with normal renal function. If the total carboplatin dose is calculated based on IDMS-measured serum creatinine using the Calvert formula, carboplatin dosing could be higher than desired and could result in increased drug-related toxicity...."cont'd