Medicines and the older adult (Changes that affect the action of medicines…
Medicines and the older adult
Pharmacokinetics is how drugs are absorbed, distributed, metabolised and excreted.
Pharmacodynamics is how the body is affected by the drugs at the cellular level in relation to the target organ.
Changes that affect the action of medicines within the body
Decline in glomerular filtration rate which may affect medication concentration within the body, particularly those that are cleared through the kidneys.
Decline in hepatic blood flow affects serum concentration and volume of distribution of substances that are metabolised by the liver.
Slows down the delivery of medications that are normally rapidly absorbed.
Delayed clearance of substances that rely on the cytochrome P-450 system.
Decrease in total body water and increased in body fat proportion to lean body mass can alter medication actions.
Medicines that are distributed primarily in body water or lean body mass may reach higher serum concentrations and their effects may be more intense.
Fat soluble substances may have a prolonged duration of action, be more erratic in their effects and have less intense immediate effects.
Changes in receptor sensitivity causing older adults to be more or less sensitive to medicines.
Changes in homeostatic mechanisms such as thermoregulation, fluid regulation and baroreceptor control can affect pharmacodynamics.
Changes in body size affects both the therapeutic and adverse effects of substances, requiring adjusted doses.
Changes that affect behaviours related to taking medications
Knowledge about the purpose of the substance
ability to distinguish the correct container
ability to read and comprehend directions
ability to hear and remember verbal instructions
Ability to swallow oral preparations
Risk Factors that Affect Medicines
Pathological processes can exacerbate age-related changes such as malnutrition further decreases serum albumin, thereby increasing both the therapeutic and adverse effects of highly protein-bound medications.
Heart failure decreases both the metabolism and the excretion of most medications.
Inappropriate Prescribing Practices
Polypharamacy or the use of more medications than have been clinically indicated.
Can be the result of consultations with multiple providers who usually do not communicate with each other about the patients.
Medical Practitioners lack of information about the medications obtained from a variety of sources such as herbs and about a persons lack of treatment adherence.
Patients fear of disclosing information about home remedies or medications from other sources and about self-directed changes to their medication regimen.
Nursing Assessment of Medication Use and Effects
Determine the effectiveness of the medication regimen
Identify any factors that interfere with the correct regimen
Ascertain risks for adverse effects or altered therapeutic actions
Detect adverse medication effects
Identify teaching needs with regard to medications
Nursing Interventions to Promote Safe and Effective Medication Management
Requires coordinated efforts from nurses, pharmacists and prescribing practitioners.
Nurses have a major role in preventing and identifying adverse effects
Medication reconciliation is the process of identifying a persons medication errors.
Teaching about medication and herbs
Addressing factors that affect adherence
Decreasing the number of medications