Drug therapy in haemodialysis patients. Special considerations in the elderly

End-stage renal disease (ESRD) is the stage of renal failure at which an individual requires dialysis therapy or a renal transplant to survive. The prevalence of ESRD is disproportionately higher among patients aged > 65 years, and the average age of new ESRD patients is continually rising in the US Medicare population. Medication management in this population is challenging because of the combination of multiple comorbid disease states, a plethora of medications and the added dimension of dialysis therapy, as well as pharmacokinetic and pharmacodynamic changes attributable to the aging process. Cardiovascular disorders such as hypertension, coronary artery disease, congestive heart failure and arrhythmias are common in elderly patients with ESRD, and account for most of the deaths in this population. Constipation is common in patients aged > 65 years, and its incidence is even higher among those receiving dialysis. Pain management is of particular concern because elderly dialysis patients are frequently prescribed inappropriate pain relief regimens. Many healthcare practitioners do not realise that patients with uraemia are at a higher risk of bleeding caused by nonsteroidal anti-inflammatory drugs than are patients with normal renal function. In addition, most practitioners do not appreciate that virtually all opioids (narcotics) and their active metabolites accumulate in patients with renal failure, leading to an increased risk of narcosis. Infectious complications are frequent in the ESRD population, with dialysis access infections and pneumonia being the 2 most common infections seen in hospitalized patients receiving dialysis treatment. The establishment of vaccination programmes for the prevention of hepatitis B, influenza and pneumococcal infections is important because of the increased risk of these disease in this population. Unfortunately, these high-risk patients display, in general, a decreased immunogenic response to vaccinations. This article addresses some of the practical issues that surround the medication management or prevention of these particular diseases in elderly patients undergoing haemodialysis. Specifically, we discuss the pharmacokinetic and pharmacodynamic changes that occur with specific medications in such patients. Drug dialysability is also discussed.