Renal, Urology and Electrolytescommon
A 76-year-old woman taking perindopril for hypertension and regular ibuprofen for knee osteoarthritis presents after three days of vomiting and watery diarrhoea. She has dry mucous membranes, a pulse of 104/min, and her systolic blood pressure falls 22 mmHg on standing. Blood tests show creatinine 240 micromol/L (45-90; her baseline three months ago was 85), urea 22 mmol/L (2.5-8.0) and potassium 5.3 mmol/L (3.5-5.2). Urinalysis is bland and a bladder scan shows minimal residual volume. In addition to withholding perindopril and ibuprofen, which one of the following is the most appropriate initial management?