Background The elderly are very different from normal adults in terms of physiology, pharmacokinetics and pharmacology. In particular, the pharmacological function of the side events of a drug due to inhibition of receptor reactivity decreases and homeostasis reaction appears to be better.

Purpose The aim of this study was to evaluate the side events and associated risk factors in the elderly when taking oral opioids.

Material and methods In the VHS Medical Centre from January 2012 to December 2012, male adults >65 years of age were examined by selecting three types of drugs (codeine phosphate, morphine sulfate and oxycodone HCL) among patients prescribed an oral narcotic analgesic. Basic information on patients was collected for further details: underlying diseases, previous experience, taking drugs, period and daily prescription. Side effects were investigated in patients.

Results Side effects from 66 of 329 patients (20%) were reported. The most frequently reported symptoms were 16 cases of constipation (24.2%), nausea in 14 cases (21.2%), oedema in 12 cases (18.2%), pruritus in 8 cases (12.1%) and headache in 5 cases (7.6%). Variables that showed significant adverse drug events were weight, BMI, underlying disease and previous drug experiences. Following multivariate analysis, cancer disease (OR=0.060, 95% CI=0.007 to 0.512) and previous drug experience (OR=14.782, 95% CI=1.904 to 114.762) were statistically significant. Among the 66 cases, adverse gastrointestinal side effects were reported in 30 cases (45.5%). Statistically significant variables were body weight, underlying disease, previous drug experience and drug use period. In multivariate analysis, independent variables for gastrointestinal adverse events from narcotic analgesic were observed for body weight (OR=1.044, 95% CI=1.001 to 1.088) and cancer disease (OR=0.056, 95% CI=0.004 to 0.756).

Conclusion Previous experience of drugs in elderly patients was considered a prognostic factor that can predict side effects and gastrointestinal side effects after oral opioid therapy.

References and/or Acknowledgements

1. Cepeda MS, Farrar JT, Baumgarten M, et al. Side effects of opioids during short-term administration: Effect of age, gender, and race. Clin Pharmacol Ther 2013;74:102–12.

References and/or AcknowledgementsNo conflict of interest.