Low drug doses may improve outcomes in chronic disease, medical researchers have argued.
Writing in today's Medical Journal of Australia, two medical professors from the University of Western Australia have claimed that many drugs are prescribed at or near maximum recommended doses for the treatment of chronic disease despite the lack of good evidence that this is necessary.
"Lowest recommended drug doses are often not considered, even in mild disease, probably because of concern about sub-therapeutic dosing," they wrote.
"Clinicians may prescribe high doses because clinical practice guidelines and specialist opinion often encourage aggressive treatment. Higher-than-necessary maintenance doses may also be used because of insufficient communication between hospital specialists and general practitioners regarding dose adjustment during long-term follow-up."
According to the authors, there is considerable evidence of good efficacy with much lower doses than in the past of a variety of established therapies — for example, aspirin for cardiovascular disease, thiazides for hypertension, and inhaled fluticasone for asthma.
The case for low-dose pharmacotherapy in older patients is particularly pertinent, they argue, with adverse drug reactions one of the leading causes of hospital admissions in older people.
"If low doses provide sufficient efficacy in chronic disease, the associated reduction in adverse effects should improve quality of life, particularly for drugs that affect the central nervous system, such as psychotropics and analgesics. The lowest effective dose is also likely to improve patient compliance with medication."
The professors called for more reliable research into optimal drug doses.
"The emerging evidence that low drug doses may be as effective as high doses in the management of chronic disease, with the advantages of reduced adverse effects and potentially improved quality of life, deserves systematic evaluation. Sufficiently powered studies are needed to address important outcomes at different doses, and research is required to establish the best measures for reliable clinical monitoring that can guide optimal dosage," they said.