Risk of drug-related problems for various antibiotics in hospital: assessment by use of a novel method

To investigate the use of antibiotics in hospitals, to explore drug-related problems (DRPs) linked to antibiotics and to introduce a novel way of expressing the risks accompanying use of various antibiotics.

Patients from internal medicine departments in four Norwegian hospitals were prospectively included in 2002. Demographics, drugs used, medical history, laboratory data and clinical/pharmacological risk factors were recorded. DRPs were identified by clinical pharmacists and assessed in multidisciplinary hospital teams. A new term, the drug risk ratio, was established and defined as the number of times the antibiotic was associated with DRPs in relation to the number of times it was used.

Out of the 668 patients included, 283 patients (42%) used antibiotics (AB users). AB users were older (76.2 vs. 73.9), used more drugs on admission (5.1 vs. 4.4) and had more DRPs (3.0 vs. 2.2) than non-users. The DRP categories no further need for drug, non-optimal drug and non-optimal dose were most frequently observed. The drug risk ratio, calculated for 12 antibiotic groups, was highest for aminoglycosides (0.77), beta-lactamase-resistant penicillins (0.56), macrolides (0.54) and quinolones (0.48) and lowest for first- and third-generation cephalosporins, 0.17 and 0.13, respectively.

Nearly half of the hospitalised patients were prescribed antibiotics and antibiotic associated DRPs occurred frequently. The drug risk ratio for the different antibiotic groups varied with a factor of six from the lowest to the highest. A high drug risk ratio would alert of antibiotics which require heightened awareness when going to be used in clinical practice.