Exposure to potential drug interactions in primary health care.
OBJECTIVE
To analyse the prevalence of potential drug interactions, and to identify patients particularly prone to drug interaction.


METHODS
Database study (Odense University Pharmacoepidemiologic Database).


METHODS
Individuals exposed to polypharmacy in 1999 were examined for potential drug interactions.


METHODS
Inhabitants of the County of Funen (n = 471 732).


METHODS
Prevalence of potential drug interactions.


RESULTS
One-third of the population were exposed to polypharmacy and among these 15% were exposed to drugs carrying a risk of harmful interaction. Among the elderly with polypharmacy, 25% aged 60-79 years and 36% over 80 years received drugs carrying the risk of interaction. Among individuals exposed to potential drug interaction, 62% were exposed only to one drug interaction and 38% to two or more different drug interactions. The drugs accounting for the highest number of potential interactions were diuretics, NSAIDs, ACE-inhibitors, digoxin, oral antidiabetics, calcium channel blockers, anticoagulants and beta-blockers. When focusing only on major drug interactions, potassium-sparing diuretics and oral anticoagulants were the most frequently involved drugs.


CONCLUSIONS
Elderly patients exposed to polypharmacy should be kept under intensified monitoring as they are at increased risk of clinically significant drug interactions.
Bjerrum
Lars
L
Research Unit of General Practice, University of Southern Denmark, Odense. lbjerrum@health.sdu.dk
Andersen
Morten
M
Petersen
Gert
G
Kragstrup
Jakob
J
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003718:Denmark / Q000453:epidemiology; D004347:Drug Interactions; D005194:Family Practice / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D019338:Polypharmacy; D012307:Risk Factors