Appropriate prescription of drugs in elderly patients is one of the biggest current challenges in clinical geriatrics. As is already known, the elderly often have multiple concomitant chronic conditions (multi-morbidities), which require the simultaneous use of multiple drugs (polypharmacy), which carries an increased risk of drug interactions and thus of adverse reactions.1
Polypharmacy is often a direct consequence of applying guidelines to the geriatric population. These guidelines are in fact often developed for a specific pathology, and do not take potential drug interactions into account. Recently published work by Dumbreck and colleagues2 shows how the drugs indicated in three guidelines from the National Institute for Health and Care Excellence (NICE) - those for heart failure, depression and type 2 diabetes mellitus - can result in numerous interactions that are potentially risky to health when combined with medications indicated in NICE guidelines for the treatment of other chronic diseases. There are in fact few guidelines that consider whether the patients may have concurrent diseases and, for this reason, might be taking other medications.
This arises from the fact that because of their complexity, older patients are poorly represented in major clinical trials and consequently, in the guidelines based on them. This therefore opens up an important gap between theory and practice, which today poses one of the major challenges in correct prescribing to the elderly.
Although there are specific regulatory pathways for the development and marketing of drugs, pharmacotherapy it is still far from comprehensively considered. Drugs have a network effect that goes far beyond a specific target, particularly in patients with multiple diseases. Many unexpected adverse effects, even serious ones, may only emerge during post-marketing surveillance, after many patients have used the drug and have already been exposed to the potential risks.
The Italian data
In this context, work published in 2013 assessed the prevalence and characteristics of adverse drug reactions in the elderly using pharmacovigilance data from an Italian hospital.3 The researchers sought to identify the contribution of specific drugs, therapeutic categories and drug-drug interactions in the development of adverse reactions. The main adverse reactions were bleeding, allergic reactions, excessive prolongation of the INR and neurological and neuropsychiatric symptoms. The drugs most frequently involved were warfarin, acenocoumarol and allopurinol, whilst the therapeutic categories most often involved were haematological agents and proton pump inhibitors. With regard to interactions potentially involved in ADRs, the most frequently found contraindicated association was that between warfarin and heparin. The most frequently found interactions were statin-warfarin, warfarin-allopurinol and warfarin-amiodarone, whilst amongst the moderate interactions were those between warfarin and proton pump inhibitors. In particular, the proton pump inhibitors emerged as the most frequently over-prescribed in cases where there was no real evidence-based indication, often in patients who were already taking several medications. Even allopurinol was often inappropriately prescribed for asymptomatic hyperuricaemia.
What is missing?
How can you avoid entering the cascade of problems that starts with inadequate guidelines, continues on to a polypharmacy and ends in an increased risk of adverse drug reactions?
Firstly, the necessity of adopting tools for the global assessment of the elderly, which makes it possible to consider all of the factors that could indirectly influence the effectiveness of a drug, and which gives priority to the diseases and their treatments, needs to be emphasized.
Moreover, the agencies and scientific societies responsible for developing guidelines should explore the possibility of using electronic systems that allow simultaneous access to multiple guidelines, and which assess the risks of drug interactions.
Finally, the periodic and systematic review of treatments should be encouraged, possibly using, in order to support prescribing, integrated and technologically advanced tools for assessing potentially inappropriate prescribing, and for establishing a personalized treatment regimen, that takes the conditions, priorities and not least the needs of the individual patient into account.
1 Centre for Ageing Medicine, Polyclinic A. Gemelli, Catholic University of the Sacred Heart, Rome
2 Geriatrics A, Azienda Ospedaliera Universitaria Integrata, Verona
- J Clin Pharm Ther 2009;34:377-86. CDI
- Brit Med J 2015;350:h949. CDI
- Eur J Intern Med.2014;25:843-6. CDI