Chapter 3: Inducers Decrease Substrate Drugs

Question 1

Antiepileptic drug (AED) CYP inducers + other drugs metabolized by CYP enzymes

Answer 1

Increased substrate (drug) metabolism will cause decreased drug levels and decreased drug effects. With AED loss of seizure control

Question 2

Rifampin + CYP and P-gp substrates

Answer 2

Concentration of substrate drugs will greatly decrease

Question 3

CYP3A4 inducers + opioids that are CYP3A4 substrates (fentanyl, hydro, oxy, methadone)

Answer 3

Increased metabolism results in decreased opioid concentration; analgesia will decrease

Question 4

CYP2D6 UMs + prodrugs that are CYP2D6 substrates (tramadol and codeine)

Answer 4

No CYP2D6 inducers, but UMs produce twice as many enzymes the prodrug will be converted more rapidly to active drug.
Increase in active concentration= toxicity/risk of fatality

Question 5

CYP3A4, P-gp inducers + CNIs + mTOR kinase inhibitors

Answer 5

Increased drug metabolism results in decreased transplant drug level and increase risk of rejection

Question 6

Smoking (induces CYP1A2) + some antipsychotics, antidepressants, hypnotics, anxiolytics, caffeine, theophylline, warfarin

Answer 6

Smokers who quit will have increased drug concentrations causing toxicity

Current smokers will have decreased substrate levels