Geriatric psychopharmacology is shaped by aging changes in pharmacokinetics, accumulated polypharmacy, anticholinergic burden, and fall risk. The general principle is "start low, go slow" — but the specifics matter, and getting them right is what makes the difference between helping the elderly patient and harming them.
- Class
- Geriatric prescribing framework
- Mechanism
- Aging changes: reduced renal function (lower clearance), reduced hepatic metabolism (slower CYP activity for some drugs), altered body composition (more fat, less lean mass), CNS more sensitive, polypharmacy (drug-drug interactions)
- FDA indications
- All psychiatric disorders — adjusted for age-specific considerations
- Key adverse effects
- Class concerns in elderly: anticholinergic burden (cognitive impairment, falls, urinary retention), benzodiazepines (falls, confusion), antipsychotics (mortality black box in dementia-related psychosis), TCAs (anticholinergic, cardiac), lithium (renal clearance changes)
Beers Criteria and STOPP/START identify potentially inappropriate medications in elderly. General principles: start at 25-50% adult dose, titrate slowly, minimize anticholinergic burden, careful drug-drug interaction screening, fall risk awareness, screen for cognitive changes, address polypharmacy. Specific agents preferred: sertraline, escitalopram (vs. paroxetine — anticholinergic). Mirtazapine for depression with insomnia/anorexia. Avoid TCAs when possible.
Aging changes pharmacokinetics in predictable ways. Renal clearance declines (renally cleared drugs accumulate — lithium, gabapentin, paliperidone). Hepatic CYP activity decreases for some drugs. Body composition shifts toward more fat (lipophilic drugs distribute differently and accumulate). The CNS becomes more sensitive to most psychotropics — the same dose that worked at 50 may be too much at 80.
Geriatric psychopharmacology follows one governing principle — 'start low, go slow' — because aging changes pharmacokinetics, pharmacodynamics, and vulnerability to harm.
Mechanism note: Geriatric prescribing is governed by reduced clearance, heightened CNS sensitivity, and polypharmacy — making low doses, slow titration, anticholinergic/benzodiazepine avoidance, and deprescribing the core disciplines.
Start at 25-50 percent of adult doses for most psychotropics in elderly patients. Titrate slowly. Reassess regularly. The "right dose" in geriatrics is often half what it would be in a younger adult.
Anticholinergic burden is one of the most underrecognized causes of cognitive decline in elderly polypharmacy. Multiple anticholinergic medications combining produce dry mouth, constipation, blurred vision, urinary retention, AND cognitive impairment that may look like dementia. Common offenders: paroxetine, TCAs, diphenhydramine, hydroxyzine, oxybutynin, many "PM" sleep formulations. Sertraline and escitalopram are the preferred SSRIs in elderly patients partly because of their low anticholinergic profile.
Beers Criteria identify medications that are potentially inappropriate in older adults. Useful reference for prescribing review. STOPP/START criteria similar. Periodic medication review identifying medications that could be discontinued is part of geriatric psychiatric care.
Fall risk rises with psychotropics through multiple mechanisms — sedation, orthostasis, anticholinergic effects, EPS. Falls in elderly cause fractures, head injuries, hospitalizations, deaths. Risk-benefit must include fall risk explicitly.
Benzodiazepines are particularly problematic in elderly — heightened cognitive impairment, fall risk, dependence. When unavoidable, use LOT (lorazepam, oxazepam, temazepam) glucuronidation-only agents, short-term, lowest dose.
For the elderly patient, the right prescription is often less medication, more carefully chosen, more carefully dosed.