Chapter 3: Inhibitors that Increase Substrate Drugs

Question 1

CYP3A4 inhibitors + CYP3A4 substrates

Answer 1

Decreased CYP3A4 substrates (i.e drugs) metabolism will cause increased drug levels, ADR, and toxicity

Question 2

Valproate + Lamotrigine

Answer 2

Valproate is an inhibitor of lamotrigine metabolism, increases lamotrigine levels and increasing risk for skin rxns (SJS/TEN)

Question 3

MAO inhibitors + drugs/food that increase Epi. NE, DA +drugs that increase 5-HT

Answer 3

MAO enzyme metabolizes Epi, NE, Da, tyramine, and 5-HT.
Blocking MAO with an inhibitor will increase Epi, NE, and DA and can cause hypertensive crisis.
High 5-HT can causes serotonin syndrome
Do not use together!! 2 weeks washout period

Question 4

CYP2D6 inhibitors +CYP2D6 substrates

Answer 4

Inhibitors: amiodarone, fluoxetine, paroxetine, fluvoxamine

Decrease drug metabolism, increased ADRs/toxicity

Question 5

CYP3A4, P-gp inhibitors + Calcineuron inhibitors (CIs) or mTOR inhibitors

Answer 5

Decreased drug metabolism, increased ADRs/toxicity, including: increased BP, nephrotoxicity, metabolic syndrome, and other)