- Relevant drug guides provide data about dosing for the elderly and debilitated clients; also see the Geriatric Tab as well as Geriatric and Dose Considerations in the Drugs A-Z Tab.
- Elderly or debilitated clients are started at lower doses, often half the recommended adult dose. This is due to:
- Decreases in GI absorption
- Decrease in total body water (decreased plasma volume)
- Decreased lean muscle and increased adipose tissue
- Reduced first-pass effect in the liver and cardiac output
- Decreased serum albumin
- Decreased glomerular filtration and renal tubular secretion
- Time to steady state is prolonged
Because of decrease in lean muscle mass and increase in fat (retains lipophilic drugs [fat-storing]), reduced first-pass metabolism, and decreased renal function, drugs may remain in the body longer and produce an additive effect.
ALERT: With the elderly, start doses low and titrate slowly. Drugs that result in postural hypotension, confusion, or sedation should be used cautiously or not at all.
- Poor Drug Choices for the Elderly – Drugs that cause postural hypotension or anticholinergic side effects (sedation).
- TCAs – anticholinergic (confusion, constipation, visual blurring); cardiac (conduction delay; tachycardia); alpha-1 adrenergic (orthostatic hypotension [falls])
- Benzodiazepines – the longer the half-life, the greater the risk of falls. Choose a shorter half-life. Lorazepam (T½ 12–15 h) is a better choice than diazepam (T½ 20–70 h; metabolites up to 200 h).
- Lithium – use cautiously in elderly, especially if debilitated.
- Consider age, weight, mental state, and medical disorders and compare with side-effect profile in selecting medications.
- Antipsychotics – increased mortality in elderly with dementia-related psychosis.