Ch.36: Drug Interactions (Vickroy)

Question 1

what is a drug interaction?

Answer 1

change in the pharmacological profile of a drug that is caused by concurrent administration of one or more other drugs

Question 2

possible consequences of drug interaction

Answer 2

altered therapeutic efficacy
altered duration of action
altered intensity of side effects
unveil novel effects

Question 3

Drug interaction facts

Answer 3

• can occur w/ all classes of drugs
• some predictable, but many are not
• often not species dependent
• frequency increases geometrically with the number of drugs that are co-administered to a patient**

Question 4

Types of direct physical-chemical interactions

Answer 4

• drugs in acidic/alkaline media
• direct binding
• solid surface binding

Question 5

Common types of drug interactions

Answer 5

direct physical-chemical interactions
PK interactions
PD interactions
physiological interactions

Question 6

types of PK interactions

Answer 6

can occur during absorption (i.e. anesthetics w/ EPI, oral drugs with antacids), distribution, bioactivation, inactivation, or elimination

Question 7

examples of interactions that affect drug elimination

Answer 7

• competition among drugs atrenal tubular acid transporters

- gaseous anesthetics and respiratory depressants

Question 8

examples of interactions that affect drug metabolism**

Answer 8

• metabolic inducers dec. duration/potency of other drugs
• metabolic inhibitors inc. duration/potency of other drugs
• prodrugs
• drugs w/ active metabolites

Question 9

Name 3 prodrugs

Answer 9

enalapril
benazepril
cyclophosphamide

Question 10

NSAIDs + corticosteroids –>

Answer 10

increased GI damage

Question 11

aminoglycosides + amphotericin B –>

Answer 11

increased nephrotoxicity

Question 12

diuretics + digitalis, antiarrhythmics, or muscle relaxants –>

Answer 12

toxicity, dec. efficacy