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Laurence A Goldberg
The theme of this year’s ESCP Spring Conference was “Clinical pharmacy and the ageing patient”. Topics discussed included pharmaceutical care research in the community, compliance, polypharmacy and pharmacodynamics in the elderly. Some of the highlights are presented here.
Pharmaceutical care research in the community pharmacy setting
Research involving disease-specific interventions is easier to manage than that involving generic interventions and the outpatient setting is easier to manage than in the communi
ty pharmacy setting, according to Professor James McElnay (Queen’s University, Belfast). These conclusions were drawn from his experience with three types of studies of interventions in pharmaceutical care.
The multicentre PEER study was concerned with the effects of a generic intervention in community pharmacy setting, on patients with multiple disease states. This randomised, controlled, longitudinal study was designed to investigate the impact of pharmaceutical care and the views of patients. Eligible patients were aged 65 years or older, were taking four or more prescribed medications and were living in the community. At the intervention sites, pharmacists were trained in the delivery of pharmaceutical care and a reference manual was provided, while those at the control sites were trained in data collection only. The key interventions were assessing actual or potential drug-related problems, taking action to educate patients, improving compliance and rationalising treatment regimens. The outcome measures were health-related quality of life, costs of healthcare and intermediate measures such as patient knowledge and compliance. The results showed better control of medical conditions and high levels of satisfaction among intervention patients. In addition, pharmacists and GPs had a positive opinion of the approach. There were also cost-saving and quality-of-life improvements in some countries. While there were some significant trends in the data the study suffered from a high drop-out rate as patients and some pharmacies withdrew for a variety of reasons, concluded Professor McElnay.
The second study concerned only patients with asthma. The results of this randomised, controlled study showed a marked improvement in health-related quality of life, improvements in peak expiratory flow rate, and a decrease in the number of hospitalisations over a 12-month period. Moreover, self-reported symptoms were improved. The overall drop-out rate was 20% compared with 40% for the PEER study.
The third study concerned outpatients with congestive heart failure. A list of pharmaceutical care interventions was defined. Participating patients were asked to keep a diary card on which they recorded physical activity, tiredness, shortness of breath, ankle swelling, body weight, nocturia and compliance with medication over a period of 12 months. The results showed improvements in exercise tolerance, quality of life and a variety of clinical measurements. In addition, there were improvements in compliance with both medication and lifestyle adjustments. Very few patients had withdrawn from the study or died and the results convincingly indicated a significant positive impact of pharmaceutical care.
Turning to risk factors for drug-related problems, Professor McElnay said that it was important to have ways of identifying which patients would benefit most from pharmaceutical care. A study carried out in 522 elderly patients to assess the risk of multiple unplanned hospital admissions had identified a list of psychosocial factors associated with decreased compliance:
Especially important were the patients’ beliefs about their diseases. “Many elderly people have completely wrong ideas about their diseases and medicines – we must get over these hurdles before we can achieve anything with pharmaceutical care”, he advised.
The implications of his experience for future research involving community-dwelling elderly patients could be summarised under three headings; structure, process and outcome. Single disease states are easier to study than generic programmes and pharmacists and patients should participate in designing the interventions. Statisticians and economists should be involved at the design stage and the study should not last for more than 12 months. The outpatient setting is easier to manage but, if community pharmacies are used, regular training and support must be provided. Professor McElnay recommended that patients with the greatest need for pharmaceutical care should be targeted using published data on risk factors. Patient beliefs and psychosocial factors should also be taken into account.
Outcome measures should include clinical, humanistic and economic measures. It is critical not to include too many outcomes in order to avoid patient and pharmacist fatigue.
Compliance, information and medication surveillance
Systematic pharmaceutical care to detect and resolve drug-related problems (DRPs) is the key to successful management of the multiple drug therapy that is often seen in elderly patients, said Dr Foppe van Mil, Pharmacy Practice Consultant from Zuidlaren, The Netherlands.
“Elderly” is often defined as the over-65 age group but this definition embraces a wide range of individuals from active professionals to frail elderly people with dementia. Dr van Mil suggested that it is better to consider a number of risk factors for DRPs rather than using age alone to identify those patients who would benefit most from pharmaceutical care.
Elderly patients tend to suffer from more chronic conditions than younger patients and some pathologies are exclusive to the elderly. In addition, more physicians are involved and often it is not clear which physician takes overall responsibility. Dr van Mil noted that in the USA 40% of over 65s are reported to receive more than five medications and, in addition, many were also taking dietary supplements. Predictors of multiple drug use have been identified as:
However, overall polypharmacy is very badly researched and the results of many studies have to be interpreted with care, he said.
It is important to have a systematic approach to the delivery of pharmaceutical care, according to Dr van Mil. The first step, fundamental to all pharmaceutical care, is to build good relationships with the patient and the physician. Next, the patient should be assessed – this involves assessment of hearing, sight, orientation and whether or not they can read and do actually read. Once these fundamentals are in place, an inventory of medicines used and conditions is compiled. DRPs are identified and prioritised and the most important ones dealt with first. Ongoing pharmaceutical care involves multiple counselling sessions supported by written material, contact with doctors and nurses, and monitoring.
Pharmacodynamics in the elderly
It is impossible to assess pharmacodynamic changes in the elderly without considering pharmacokinetic changes because the clinical effect is the result of the interaction between the two effects, explained Professor Hartmut Derendorf (University of Florida, USA). Changes in pharmacokinetics govern exposure to a drug while changes in pharmacodynamics govern sensitivity. Viewed in this way, it is easy to see that pharmacodynamic and pharmacokinetic changes could reinforce or neutralise each other or one effect might predominate. He described examples of a number of situations where an understanding of these phenomena is helpful.
The pharmacokinetics of midazolam do not change with age and yet elderly patients require considerably smaller doses for induction of anaesthesia than young patients. This is because the sensitivity of the CNS changes with age and a smaller dose is required to achieve the same effect. Similar patterns are seen with prazosin and atracurium. An example of the opposite effect is propranolol. In this case, sensitivity is decreased in the elderly, but the pharmacokinetics do not change, so a higher dose is required to produce the same effect.
An example of reinforcement of effects is diazepam. In the elderly the half life of the drug is prolonged and sensitivity is increased. As a result very small doses are needed to achieve a clinical effect. Smaller doses of triazolam are also required in the elderly but for a different reason. In this case there is no change in sensitivity but the pharmacokinetic changes are such that elderly patients are exposed to a higher level for a given dose than younger patients. A different effect again is seen with morphine. This drug is metabolised more rapidly by the elderly, but sensitivity is increased and this effect predominates.
Professor Derendorf concluded that more studies are needed to find out if and when dosing adjustments are needed in the elderly. An understanding of the physiological changes of ageing and the mechanisms of drug action will allow a rational approach to these questions, he added.
Pharmacodynamic changes are difficult to interpret and scarce information is available, said Professor Amilcar Falcao (University of Coimbra). In reviewing age-related changes in drug handling he pointed out that pharmacodynamic changes occur at a variety of sites at the drug–receptor interface. They are dependent on receptor numbers and affinity, signal transduction mechanisms, cellular mechanism and homeostatic regulation. A further complicating factor is the way in which age is defined in research studies. Although chronological age is often used for patient selection it might be more important to find markers for biological age, he said.
In the discussion that followed Professor Falcao said that much drug therapy in the elderly is compromised by poor compliance. He suggested that clinical pharmacists should focus their efforts on outpatients and clinics and should provide both written and oral information to patients. They should also offer family support, in particular to patients with obvious problems. Other key functions should be simplification of dosing regimens, and follow-up and monitoring of patients. Professor Derendorf added that there is a desperate need for more data as this area has been overlooked.
Asked about the possibility of pharmacist prescribing, Professor Derendorf replied that it did not matter who did the prescribing provided that they were adequately trained. Professor Falcao said that they would have to know the diagnosis and work in partnership with the other members of the healthcare team.