Elderly Pharm

Question 1

does amount absorbed (bioavailability) change with age?

Answer 1

no!

Question 2

how does peak serum concentration change with age

Answer 2

may be lower and delayed

Question 3

how do drugs with extensive first-pass effect change with age?

Answer 3

bioavailability may increase because less drug is extracted by the liver, which is smaller with reduced blood flow

Question 4

factors that affect absorption

Answer 4

route of administration, what is taken with the drug, and comorbid illnesses. divalent cations can affect absorption of fluoroquinolones, enteral feedings interfere with absorption of some drugs, drugs that affect GI motility can affect absorption

Question 5

what happens to gastric pH when you age?

Answer 5

less gastric acid causing higher pH in the stomach. may impact absorption of drugs such as cations.

Question 6

effects of aging on volume of distribution

Answer 6

decreased body water = lower VoD for hydrophillic drugs
lower lead body mass = lower VD for drugs that bind muscle
increased fat stores = higher VD for lipophilic drugs
lower plasma protein = higher percentage of drug that is unbound

Question 7

why might metabolic clearance of a drug by the liver be reduced?

Answer 7

aging decreases liver blood flow, size, and mass. liver is most common site of drug metabolism

Question 8

phase I and phase II pathways

Answer 8

phase I convert drugs to metabolites with greater, lesser, or the same effect as the parent compound. Phase II pathways convert drugs to inactive metabolites that do not accumulate

Question 9

what phase of metabolism is preferred for old patients

Answer 9

phase II

Question 10

other factors that affect drug metabolism

Answer 10

gender, hepatic congestion from heart failure, smoking

Question 11

effects of aging on the kidney

Answer 11

decreased kidney size, renal blood flow, number of functioning nephrons, and renal tubular secretion. results in lower GFR

Question 12

creatinine clearance and aging

Answer 12

decreased creatinine production and lower GFR leads to serum creatinine staying in the normal range, masking change in creatinine clearance!

Question 13

2 ways to measure creatinine clearance

Answer 13

24 hour urine collection. Crockroft and Gault equation

Question 14

successful pharmacotherapy

Answer 14

uses correct drug, prescribes correct dosage, targets the correct condition, is appropriate for the patient

Question 15

most common drugs involved in ADE

Answer 15

cardiovascular, CNS, and musculoskeletal meds. meds with a narrow margin of safety

Question 16

factors that increase risk of drug-drug interactions

Answer 16

increased number of meds consumed, multiple prescribers, multiple pharmacies, physiologic and pharmacokinetic changes

Question 17

most common adverse effects of drug-drug interactions

Answer 17

confusion, cognitive impairment, arterial hypotension, acute renal failure

Question 18

principles of prescribing for older patients

Answer 18

start at low dose, titrate upward slowly. avoid starting two drugs at the same time