Increased Sensitivity to Many Drugs: The problems of decreased body size, altered body composition (more fat, less water), and decreased liver and kidney function cause many drugs to accumulate in older people’s bodies at dangerously higher levels and for longer times than in younger people.
Age-related changes in physiology and pharmacokinetics (how drugs are used in the body) lead to increased drug sensitivity and potentially harmful drug effects. This report addresses the heightened sensitivity to drug effects seen in older adults.
The elderly are particularly at increased risk of adverse drug reactions (ADR)  attributed in the main to polypharmacy and physiological changes affecting the pharmacokinetics and pharmacodynamics of many drugs or poor compliance due to cognitive impairment or depression.
Elderly individuals have the potential to exhibit sensitivity to a broad range of substances. This is due to internal biological changes associated with the aging body, present state of health, and genetic predisposition.
As we get older, our bodies react to drugs differently than when we were younger. The aging process, along with medical conditions, often impacts the benefits and side effects of medications.
Warfarin is one of the most common causes of medication-related hospitalizations in older adults. To reduce the risk of serious problems, one may need to apply extra care in monitoring warfarin effect (via the prothrombin blood test) and extra care in checking for interactions when a new drug is prescribed.
Older adults tend to have less muscle than younger people and generally have a higher percentage of body fat. For this reason, many older adults require lower doses of medications that have an affinity for muscle and are at increased risk for toxicity if taking medications that accumulate within adipose tissue.
The prevalence of adverse drug reactions (ADRs) increases with age, with twice as many patients aged 65 years and older being hospitalized because of ADR-related problems than their younger counterparts [Beijer de Blaey, 2002].
Reducing the risk of adverse drug events in older adults requires close monitoring of functional status, early identification of symptoms, and recognition of the impact a medication can have on multiple organ systems.
Polypharmacy and physiological changes inherent to the aging process can cause significant modifications in the pharmacokinetic and dynamic regimens of drugs, making the elderly more susceptible to adverse drug effects. Most common ADR in this population are dose-related and predictable.
Through their study, the researchers also drilled down on the way emotion sensitivity develops during adolescence. “These findings fit well with other research showing that older adults tend to have more positive emotions and a positive outlook.”
That being said it is well documented that sensitivity in sensory systems decreases with advancing age for hearing, taste, smell, vision and touch due in part to diminished numbers of specialized peripheral receptors combined with a deterioration of supporting tissues (5).
“What we observed is that older individuals don’t adapt as well to their sound environment.” This means that as we age, or ears and brain become more sensitive to sound, and years of wear and tear start to chip away at our ability to hear clearly.
As we age, changes in our body can affect the way medications are absorbed and utilized. We become more sensitive to medications, and we are more likely to experience increased side effects, drug interactions, and other adverse drug reactions.
What Older Adults Can Do to Manage Medications