Chapter 6: Drug Interactions

Question 1

drug interactions occur when

Answer 1

a patient takes more than one drug

Question 2

consequences of drug drug interactions

Answer 2

• intensification of effects (potentiates)
• reduction of effects (inhibits)
• creation of a unique response

Question 3

intensification of effects

Answer 3

increased therapeutic or adverse effects

Question 4

reduction of effects

Answer 4

reduced therapeutic or adverse effects

Question 5

creation of a uniqur response

Answer 5

combined affect does not occur when drugs are used alone; only when used together

Question 6

drugs interact through what 4 basic principles

Answer 6

• direct chemical or physical interaction
• pharmacokinetic interaction
• pharmacodynamic interaction
• combined toxiciity

Question 7

drug interaction are most common is

Answer 7

intravenous solution

Question 8

pharmacokinetic interactions

Answer 8

• altered absorption
• altered distribution
• altered renal excretion
• altered metabolism
• cytochrome P450 group of enzymes

Question 9

altered absorption

Answer 9

• elevated gastric pH
• laxatives
• drugs and depress peristalsis
• drugs that induce vomiting
• absorbent drugs
• drugs that reduce regional blood flow

Question 10

altered distribution

Answer 10

• competition for protein binding
• alteration of extracellular pH

Question 11

altered renal excretion

Answer 11

• filtration
• reabsortion
• active secretion
  via changes in blood flow, competition, or changes in pH

Question 12

which is the most important and complex mechanism in which drugs interact

Answer 12

altered metabolism

Question 13

intestinal epithelium

Answer 13

affects absorption

Question 14

placenta

Answer 14

affects drug export from placental cells to maternal blood

Question 15

blood brain barrier

Answer 15

affects drug export from cells of brain capillaries into the blood

Question 16

liver

Answer 16

affects drug export from liver into bile

Question 17

kidney tubules

Answer 17

affects drug export from renal tubular cells into the urine

Question 18

pharmacodynamic interactions at the same receptor

Answer 18

almost always inhibitory (antagonist /agonist)

Question 19

pharmacodynamic interactions at separate sites

Answer 19

may be potentitative or inhibitory

Question 20

how to minimize adverse drug drug interactions

Answer 20

• minimize number of drugs a patient recieves
• take a thorough drug history
• be aware of the possibility of illicit drug use
• adjust dosage when metabolizing inducers are added or deleted
• adjust timing of administration
• monitor patient for early signs of toxicity
• be especially vigilant when a patient is taking a drug with a low therapeutic index

Question 21

food effect on drug absorption

Answer 21

decreased absortion

Question 22

the grapefruit juice effect

Answer 22

• inhibits the metabolism of certain drugs
• raises the drugs blood levels