In the UK, older people make up a fifth of the population, but receive almost half of prescription items, the majority of which are repeats. Of those aged over 75 years, 36 per cent take four or more medicines.
The NSF for older people, published in 2001, outlines health and social care standards for older people, focusing heavily on the use of medicines by this group. Prescribing for older people requires consideration of their specific needs.
Pharmacology changes as we age. There is an age-related reduction in renal drug clearance and hepatic metabolism. This potentially increases the plasma concentration of drugs exclusively renally excreted (for example, digoxin), as well as those with extensive first-pass metabolism (for example, propranolol and opioids). There are changes in the responsiveness of target organs. Initial dosages should be low and titrated up only as necessary.
In general, older people have an increased sensitivity to drugs, particularly those acting on the CNS. The use of psychotropic drugs is a particular concern because some can increase the incidence of confusion and falls in the elderly.
Older people are also particularly susceptible to the anticholinergic effects of drugs such as tricyclic antidepressants, including blurred vision, constipation, confusion and urinary retention.
Adverse drug reactions
Polypharmacy and age-related changes in pharmacology put older people at increased risk of adverse drug reactions (ADRs). ADRs often go undiagnosed because they can present in a non-specific way, for example as confusion, constipation or unsteadiness. It is important to consider the possibility of an ADR in any older patient whose general condition has deteriorated.
The incidence of drug interactions in older people increases with age, the number of drugs being taken and the number of prescribers involved. ADRs and drug interactions are more likely after medicine changes. These changes might be intentional, but unintentional discrepancies may occur due to communication problems. Reasons for these include delayed communication from secondary care and inaccurate updating of patient records in primary care.
Pharmacist involvement, either in the community or in the practice, has been shown to reduce such unintentional discrepancies.
Patients who are confused, depressed or have poor memories might have difficulty in taking medicines, and in accommodating drug or dosage changes.
Drug regimens for older people should be kept as simple as possible. Multi-compartment compliance aids or medicines reminder charts may be useful. Patients with disabilities such as arthritis may have problems accessing medicines.
People living in nursing and residential homes are at particular risk of polypharmacy and inappropriate prescribing. Nursing home residents in the UK take an average of six to seven drugs. National minimum standards for care homes include policies around medicine use and training of care staff in basic medicines knowledge.
When prescribing for older people it is important to have clear therapeutic goals, monitor progress and ensure that drug treatment remains appropriate. A full medicines review is an important opportunity to rationalise drug therapy and check for problems.
This is especially important for patients with repeat prescriptions because these can reduce contact between doctors and patients.
Suitably trained health professionals, such as pharmacists, can carry out these reviews in clinics, pharmacies or the patient's home. The NSF recommends that all patients over 75 years should have their medicines reviewed annually. For those taking four or more medicines, it recommends every six months.
The NSF recommends that every PCT has schemes in place so older people get more help from pharmacists in using their medicines. There are also quality framework incentive points for medicine reviews for patients on four or more medications and patients with repeat prescriptions.
Another way of achieving therapeutic goals for older people is to consider non-pharmacological alternatives to treatment such as physiotherapy for osteoarthritis.
Dr Whitburn is a GP registrar in Dursley, Gloucestershire
This topic falls under section 9 of the GP curriculum (www.rcgp-curriculum.org.uk/PDF/curr_9_care_of_older_adults.pdf)
Learning pointsUnderstanding the medicine needs of older people
- Pharmacology changes with age.
- Older people are more susceptible to adverse drug reactions and interactions.
- Good communication with patients and between staff is important in simplifying drug regimens.
- Consider compliance aids and non-pharmacological treatments for older people.
- Older people should have medication reviews each 6-12 months depending on the number of medicines taken.
- DoH. NSF for older people, 2001. www.dh.gov.uk/en/Policyandguidance/Healthandsocialcaretopics/Olderpeople sservices/index.htm
- Commission for Social Care Inspection. Care Homes for Older People: National Minimum Standards, 2001. www.csci.gov.uk/PDF/care_homes_older_people.pdf.