Defining inappropriate practices in prescribing for elderly people: a national consensus panel

OBJECTIVE

To develop a consensus-based list of inappropriate practices in prescribing for elderly people.

DESIGN

Mail survey of a 32-member national panel.

SETTING

Academic medical centres across Canada.

PARTICIPANTS

Thirty-two specialists selected arbitrarily, including 7 clinical pharmacologists, 9 geriatricians, 8 family practitioners and 8 pharmacists.

OUTCOME MEASURES

Consensus that the practice would introduce a substantial and significant increase in the risk of serious adverse effect and is common enough that its curtailment would decrease morbidity among elderly people, ranking of clinical importance of the risk, and availability of equally or more effective and less risky alternative therapy.

RESULTS

The 32-member national panel developed a list of 71 practices in prescribing for elderly people and rated the clinical significance of each on a scale of 1 (not significant) to 4 (highly significant). The practices in prescribing identified fell into 3 categories: drugs generally contraindicated for elderly people, drug-disease interactions and drug-drug interactions. The mean significance rating was greater than 3 for 39 practices. For each practice, alternative therapies were recommended. There was surprising congruence among the specialists on the significance rating and the suggested alternative therapies.

CONCLUSION

The authors have developed a valid, relevant list of inappropriate practices in prescribing for elderly people, to be used in a practice-based intervention study.

Questionable prescribing for elderly patients in Quebec

OBJECTIVE

To estimate the prevalence of questionable and rational high-risk prescribing among elderly people of the three drug groups most commonly implicated in drug-related illness: cardiovascular drugs, psychotropic drugs and nonsteroidal anti-inflammatory drugs (NSAIDs).

DESIGN

Retrospective prevalence study; all prescription and billing records for the period Jan. 1 to Dec. 31, 1990, for the study sample were retrieved from the relevant provincial databases of the Régie de l'assurance-maladie du Québec.

SETTING

Quebec.

PARTICIPANTS

Regionally stratified random sample of 63,268 elderly medicare registrants who made at least one visit to physician in 1990 and were not living in a health care institution for the entire year.

MAIN OUTCOME MEASURE

Prescription information was examined for three types of high-risk prescribing: rational and questionable drug combinations, excessive treatment duration and drugs relatively contraindicated for use in elderly people.

RESULTS

Overall, 52.6% of the patients experienced one or more events of high-risk prescribing, and 45.6% experienced at least one that was questionable. High-risk prescribing was most prevalent for psychotropic drugs, and questionable prescribing was more frequent than rational prescribing in this drug group. An estimated 30.8% of the total elderly population in Quebec received benzodiazepines for more than 30 consecutive days, 12.9% received a long-acting benzodiazepine, and 13.0% received a questionable high-risk psychotropic drug combination. The prevalence of high-risk prescribing was higher among the women than among the men and increased with age until 75 to 84 years. There were significant unexplained differences between regions in the regional prevalence of high-risk prescribing, particularly of psychotropic drugs.

CONCLUSION

The prevalence of questionable high-risk prescribing, especially of psychotropic drugs, is substantial among elderly people. This may be a potentially important and avoidable risk factor for drug-related illness in elderly people.

A study of the mechanism of action of pyridoxal isonicotinoyl hydrazone at the cellular level using reticulocytes loaded with non-heme 59Fe

Pyridoxal isonicotinoyl hydrazone (PIH) has recently been identified as a new iron chelating agent with a high degree of iron mobilizing activity in vitro and in vivo which makes this compound a candidate drug in the treatment of iron overload. This study was undertaken to elucidate the mechanism of action of the iron mobilizing activity of PIH at the cellular level. An in vitro system of rabbit reticulocytes with a high level of non-heme 59Fe was used as a model of iron overload. The effects of various biochemical and physiological maneuvers on the mobilization of 59Fe by PIH from the cells were studied. The fate of [14C]-PIH in the in vitro system was also studied. Studies were also carried out using a crude mitochondrial fraction. The results indicate three phases in the iron mobilizing activity of PIH: (1) the entry of PIH into erythroid cells seems to be by passive diffusion; (2) chelation occurs mainly from mitochondria and may depend on the availability of iron in a low molecular weight, non-heme pool. Chelation seems to be enhanced by reduction of Fe (III) to Fe (II); (3) the exit of the PIH2-Fe complex is an energy-dependent process. Iron mobilization by PIH is not dependent on (Na+ + K+)-ATPase activity, external ionic composition, or external hydrogen ion concentration. Membrane fluidity does not seem to play a role in PIH-Fe mobilization. The exit of the PIH2-Fe complex is inhibited by anti-microtubule agents (vinca alkaloids but not colchicine) suggesting that the PIH2-Fe complex is actively extruded from the cell by a microtubule-dependent event.