Includes adults >65 years old

1
Includes adults gt65 years old
Geriatric Pharmacology Relevance Clarissa
Zaoirov (2009)

• Fastest growing population in US and in the
  majority of developed nations.
• 20 of hospitalizations for those gt65 are due to
  medications theyre taking Adverse Drug
  Events/Interactions are very common in the
  elderly.

2
What is different about geriatric pharmacotherapy?

• Absorption Not usually significantly altered
  with age. Reduced motility and gastric emptying
  constipation
• Distribution Change in total body composition,
  vascular changes, lower albumin production (not
  always)
• Metabolism Reduced hepatic blood flow mass,
  low CYP-450, slow biotransformation (Phase I
  metabolic pathways)
• Excretion Renal blood flow by age 80, can be
  reduced by as much as ½. Reduction in tubular
  function size.

3
Pharmacodynamic Changes

• Disturbed homeostatic mechanisms
• - Reduced compensatory tachycardia,
  baroreceptor and vasomotor response.
• - Poor thermoregulatory mechanisms
• - Cardiac Beta receptor sensitivity reduced
• - Hepatic Beta receptor sensitivity increased
• - Greater sensitivity to medications affecting
  the CNS (benzodiazepines and opioids)
• - Pre-existing depletion of dopamine
  Parkinsonism when using anti-psychotic
  medications.

4
Total Result

• These age-related changes result in greater
  therapeutic effect and increased risk of
  accumulation toxicity. (Longer ½ life)
• Complicated by alterations in metabolism,
  distribution and clearance.
• Example Benzodiazepines may cause more sedation
  and poorer psychomotor performance in older
  adults. Likely cause reduced clearance of the
  drug and resultant higher plasma levels, wider
  volume of distribution of lipophylic drug and
  active metabolites.

5
Other factors that complicate pharmacotherapy

• Polypharmacy including naturaceuticals. (Ginko
  biloba)
• Non-Compliance Issues
• Drug-Disease Interactions
• - Anticholinergics Benign. Prostatic
  Hypertrophy (BPH), constipation, dementia
• Antiarrhythmics (Type 1A) CHF (systolic
  dysfunction)
• Amphetamines Hypertension (HTN), insomnia
• Aspirin Peptic Ulcer disease (PUD)
• Atypical antipsychotics DM (Diabetes Mellitus)
• Barbiturates Depression
• Benzodiazepines COPD,dementia, falls
• Beta-blockers COPD, DM, syncope
• CCB 1st generation CHF (systolic dysfunction)
• Chlorpromazine Postural hypotension, seizures
• Clozapine Seizures
• Corticosteroids DM, PUD, COPD
• Decongestants Insomnia

6
Recommendations

• Start low and advance dosage slowly. Avoid the
  prescription cascade!
• Cockcroft-Gualt Formula (Creatinine Clearance)
  
• Beers Criteria or MAI
• ANY new symptom or disease in an elderly patient
  should be treated as Adverse Drug Event unless
  proven otherwise. (i.e.. Dementia) Constantly
  review medications for appropriateness.