Polypharmacy in a general surgical unit and consequences of drug withdrawal

Aims To identify drug usage/withdrawal in surgical patients and the relativ e risk this imposes on postoperative surgical complications. Methods A prospective survey of patients' medicines, oral intake (food/flui ds/ medicines) and postoperative complications was carried out in the Gener al Surgical Unit, Dunedin Hospital, Dunedin, New Zealand. Results One thousand and twenty-five general surgical patients aged greater than or equal to 16 years, were entered into the study. Half of the patien ts were taking medicines unrelated to surgery. On average these patients re ceived 9 different drugs (range 1-47) from a selection of 251, of which 21% were released in the last 10 years. The mean number of these drugs taken i ncreased with age, vascular surgery and other major procedures. The majorit y of patients (53%) were taking drugs for cardiovascular problems. Only 8% of admissions were on the drugs more traditionally recognized to be of impo rtance to the surgery, i.e. steroids and diabetic therapy. With respect to risk, taking a drug unrelated to surgery was associated with an increased r elative risk of a postoperative complication by 2.7 (95% C.I. 1.76-4.04) co mpared with those who were not taking any drug. Cardiovascular drugs contri buted significantly to this risk; when they were excluded from analysis, th e risk dropped to 1.8 (95% C.I. 1.14-2.93). Death may be more common in tho se taking ACE inhibitors. Drug withdrawal and complications were analysed a nd as the time without medicines increased (range 1-42 days) so did the com plication rate (chi(2) = 14.7, DF = 2, P = 0.007). Of those patients who we re taking a cardiovascular medicine and were without their normal medicines for a period of time postoperatively, 12% suffered a cardiac complication. Conclusions Many patients admitted to a general surgical ward, are taking m edicines unrelated to surgery. Drug therapy unrelated to surgery is a usefu l predictor for increased postoperative complications and one for which pre ventive action can be taken. This study provides evidence that withdrawal o f regular medicines may add significant risk to the surgery and further com plicate outcome. The longer patients were without their regular medicines t he more nonsurgical complications they suffered. Reintroduction of patients ' regular medicines early in their postoperative course may decrease morbid ity and mortality in-patients.