Geriatric Pharmacology Flashcards
How does body composition change in the geriatric
population?
Adipose tissue increases while there is a decrease in skeletal
muscle mass and total body water.
Barash PG, Cullen BF, Stoelting RK, Cahalan MK, Stock MC,
Ortega R. Clinical Anesthesia. 7th ed. Philadelphia, PA:
Lippincott Williams and Wilkins; 2013: 893.
How do hepatic mass and blood flow change with
age?
Hepatic mass decreases, and is responsible for a significant
portion of the decrease in hepatic blood flow.
Barash PG, Cullen BF, Stoelting RK, Cahalan MK, Stock MC,
Ortega R. Clinical Anesthesia. 7th ed. Philadelphia, PA:
Lippincott Williams and Wilkins; 2013: 893.
How do the changes in body composition associated
with aging affect the volume of distribution for watersoluble
and fat-soluble drugs?
In the elderly patient, total body water decreases while total
body fat increases. Thus, the volume of distribution for watersoluble
drugs such as glycopyrrolate, succinylcholine, and
gentamicin decreases while the volume of distribution for lipidsoluble
drugs such as barbiturates, benzodiazepines, and
volatile anesthetics increases.
Barash PG, Cullen BF, Stoelting RK, Cahalan MK, Stock MC,
Ortega R. Clinical Anesthesia. 7th ed. Philadelphia, PA:
Lippincott Williams and Wilkins; 2013: 893-896.
What are the two major physiologic factors that can
result in a greater initial response to a drug in elderly
patients?
They have a decreased vascular volume, which results in a high
initial plasma concentration of the drug. They also have
decreased plasma protein levels which produces an increased
concentration of the free form of the drug that exerts
pharmacologic action.
Nagelhout JJ, Zaglaniczny KL. Nurse Anesthesia. 4th ed.
Philadelphia, PA: WB Saunders Company; 2010: 1214.
How is plasma protein-binding of drugs affected by
age?
Overall, plasma protein-binding is decreased. This is due to a
decrease in the circulating albumin levels. Alpha-1 acid
glycoprotein levels, however are unchanged.
Barash PG, Cullen BF, Stoelting RK, Cahalan MK, Stock MC,
Ortega R. Clinical Anesthesia. 7th ed. Philadelphia, PA:
Lippincott Williams and Wilkins; 2013: 459.
How is the elimination half-life of pancuronium
affected by aging? What is the cause of this change?
The elimination of pancuronium is prolonged in the elderly, but
since it is eliminated primarily via the renal route, it is the
decrease in renal clearance, not hepatic clearance that
prolongs pancuronium.
Butterworth JF, Mackey DC, Wasnick JD. Morgan & Mikhail’s
Clinical Anesthesiology. 5th ed. New York, NY: McGraw-Hill;
2013: 915.
How are the elimination half-lives of atracurium and
cisatracurium affected by aging?
The elimination half-lives of atracurium and cisatracurium are
not affected substantially by age.
Butterworth JF, Mackey DC, Wasnick JD. Morgan & Mikhail’s
Clinical Anesthesiology. 5th ed. New York, NY: McGraw-Hill;
2013: 915.
How is the onset of action of nondepolarizing muscle
relaxants affected by aging?
Because of a longer circulatory time and decrease in skeletal
muscle blood flow, the onset of all muscle relaxants is up to
twice as long in elderly patients.
Butterworth JF, Mackey DC, Wasnick JD. Morgan & Mikhail’s
Clinical Anesthesiology. 5th ed. New York, NY: McGraw-Hill;
2013: 915.
How are the durations of action of diazepam,
lorazepam, and midazolam affected by aging?
Because of diazepam’s tendency to accumulate in lipid stores
and the increased fat content in elderly patients, the elimination
half-life of diazepam is increased from 30 hours to over 36
hours which can result in disorientation that may last for days
after the surgery is complete. Midazolam’s effects are
increased in the elderly, but not nearly to the same extent as
diazepam. Because lorazepam is less lipid soluble, its half-life
remains relatively unchanged in the elderly.
Butterworth JF, Mackey DC, Wasnick JD. Morgan & Mikhail’s
Clinical Anesthesiology. 5th ed. New York, NY: McGraw-Hill;
2013: 914-915.
How is bile secretion altered by aging?
Bile secretion decreases which may prolong the duration of
action of drugs eliminated in the bile.
Barash PG, Cullen BF, Stoelting RK, Cahalan MK, Stock MC,
Ortega R. Clinical Anesthesia. 7th ed. Philadelphia, PA:
Lippincott Williams and Wilkins; 2013: 893.
How is phase I drug metabolism affected by aging?
Phase I drug metabolism is decreased in the elderly.
Barash PG, Cullen BF, Stoelting RK, Cahalan MK, Stock MC,
Ortega R. Clinical Anesthesia. 7th ed. Philadelphia, PA:
Lippincott Williams and Wilkins; 2013: 893.
