Factors Modifying Drug Activity

Question 1

What are the factors in modifying drug activity?

Answer 1

Age
Weight
Sex
Pharmacogenetic
Drug Interactions
Effect of disease

Question 2

What are some factors that specifically effect the elderly?

Answer 2

May absorb drugs less completely or more slowly because of dec splanchnic blood flow or delayed gastric emptying
Reduced gastic acidity
Hypoalbuminemia
Reduction in muscle mass
Qualitative changes in drug-binding sites
Reduced renal blood flow
Dec cardiac output

Question 3

Which drug responses change with aging?

Answer 3

Changes in receptors
Changes in postreceptor signaling mechanism
Changes in homeostatic control
Disease-induced changes

Question 4

What are some impaired homeostatic mechanism in the elderly?

Answer 4

Dec activity of arotic/carotid chemoreceptors
Reduced baroreceptor reflex
Impaired thermoregulation
Inappropriate response to blood glucose and insulin
Altered neurological control of bowel and bladder

Question 5

What are some drug dispositions in peds?

Answer 5

Preterm infants
Term infants in 1 mo of life
1 mo to 2 yrs
2 ys to 12yrs 
12 yrs to 18 yrs

Question 6

What are limited in preterms that have drug issues?

Answer 6

Gfr's 1/10 of newborn
Limitation on tubular reabsoption
Glucuronidation pathway limited
Gastric acids not found or limited 
Metabolism and elimination not active
Skin not totally protective
Dec plasma albumin and total plasma protein conc
Dec drug binding ability

Question 7

Issue with drugs for term infants to 1 mo

Answer 7

Inc body water, dec body fat
Dec exocrine pancreatic function
Dec albumin conc and binding 
CYP450 slow functioning 
Phase 1 oxidation rxn reduced 
High sulfate conjugation

Question 8

Issues with drugs for 1 mo to 2 yrs

Answer 8

Rapid growth, things work pretty well

Question 9

Issues with drugs for 2 yrs to 12 yrs

Answer 9

Drug clearance inc and exceeds adult levels

Shorter half-lives and dosing requirements are frequently greater

Question 10

Issues with drugs for 12 yrs t 18 yrs

Answer 10

Sex changes
Dec drug absorption and elimination in female
Females less gastric acidity and inc gastric emptying
Estrogen dec CYP450 - dec phase I pathway

Question 11

What should be done for children with chronic illness for drugs?

Answer 11

Possible inc of drug dosages like is CF who have inc hepatic metabolism (inc drug clearance)

Question 12

Are most drugs given the peds used for the same things as adults?

Answer 12

Yes

Question 13

What is example of a drug used for adults that is different for children?

Answer 13

Caffeine - used to treat apnea

Question 14

What does tetracycline do in children it doesn’t do in adults?

Answer 14

Discolors teeth

Question 15

What are the factors used to calculate pediatric dose?

Answer 15

Age, weight, surface area

Should never exceed adult dose

Question 16

What is the standard for therapeutic dose in humans?

Answer 16

70 kg adult

Question 17

How does sex influence drug administration?

Answer 17

Hormonal difference

No real significant differences

Question 18

Pharmacogenetics

Answer 18

Abnormal biotransformation or reaction to a drug due to a genetic difference (not defect)

Question 19

Concomitant of drug therapy

Answer 19

Effect of one drug may be altered significantly by the administration of another drug
Can enhance or reduce therapeutic effects or toxicity

Question 20

What is most likely the effects of time administration?

Answer 20

Inc enzyme activity during the day probably

Question 21

What are some reason the pt does not comply?

Answer 21

Self-conscious
Reminded of disease
Does not feel sick
Adverse drug reactions (ADRs)

Question 22

How can you inc compliance to take drugs?

Answer 22

What they are taking
Why its prescribed
Which ADRs might develop
What will occur if drugs aren’t taken