Drug interactions Flashcards
when drugs interact, how can drugs influence the works of another
- alter the bioavailability of the drug or alter interactions with receptors
- loose enhancement or cause toxic effects
Which of the following best describes the primary purpose of a drug monograph?
A. To provide promotional material and marketing claims for health professionals
B. To present scientific and regulatory information essential for the safe and effective use of a drug
C. To summarize clinical opinions and off-label uses of a drug for public consumption
D. To outline historical drug development and manufacturer patents for regulatory submission
To present scientific and regulatory information essential for the safe and effective use of a drug
Why are drugs with a narrow therapeutic index more prone to dangerous drug interactions?
A. They are metabolized exclusively by the kidneys, making them unpredictable
B. They are only effective when co-administered with CYP enzyme inhibitors
C. Small changes in drug availability can lead to loss of effect or toxic side effects
D. Their absorption depends on food intake, which is highly variable
. Small changes in drug availability can lead to loss of effect or toxic side effects
Which of the following scenarios is most likely to result in enhanced warfarin-induced bleeding risk?
A. Co-administration of a CYP3A4 inducer
B. Co-administration of a vitamin K supplement
C. Use of broad-spectrum antibiotics that alter gut flora
D. Consumption of a high-protein, low-fat diet
Use of broad-spectrum antibiotics that alter gut flora
what is the mechanism of Warfarin?
- inhibits vitamin K epoxide reductase
- enzyme recycles oxidized vitamin K (KO) to reduce vitamin (KH2)
- KH2 is used to produce anti-clotting factors
what is a tool used for measuring the time required for blood to clot under a set of standard lab conditions
Prothrombin time (PT)
what does a high INR indicate?
indicates that your blood takes a looong time to clot
Which of the following best explains how vitamin K levels influence the effectiveness of warfarin therapy?
A. High vitamin K levels inhibit warfarin metabolism, increasing its potency
B. High vitamin K levels bypass warfarin’s mechanism by replenishing clotting factor production
C. Low vitamin K levels decrease warfarin absorption, reducing its anticoagulant effect
D. Low vitamin K levels activate CYP3A4, leading to faster warfarin clearance
B. High vitamin K levels bypass warfarin’s mechanism by replenishing clotting factor production
Which of the following would most likely increase the anticoagulant effect of warfarin by diminishing vitamin K availability?
A. Consuming spinach and other leafy greens
B. Taking CYP3A4-inducing anticonvulsants
C. Using broad-spectrum antibiotics that alter gut microbiota
D. Taking proton pump inhibitors to reduce stomach acid
C. Using broad-spectrum antibiotics that alter gut microbiota help increase the affects of warfarin
what is the difference btween synergism and additive interactions
synergism: when effects are GREATER than the individual effects of two drugs
additive: when effects are about the sum of the individual effects of the drugs
A patient taking benzodiazepines also consumes barbiturates and alcohol. What is the most likely mechanism underlying the potentially fatal interaction?
A. Synergistic inhibition of serotonin reuptake
B. Antagonism at GABA-A receptors
C. Additive positive modulation of GABA-A receptor activity
D. Competitive inhibition of CYP3A4 metabolism
Additive positive modulation of GABA-A receptor activity, which leads to serious effects
benzos, barbiturates and alcohol
what is serotonin syndrome?
comes from the combination of drugs that increase serotonin receptors
theses drugs activate the same signalling pathway but not the same receptor
how does drug combinations alter drug flow
They decrease bioavailbility
A patient is prescribed a new anticonvulsant known to induce CYP3A4. Which of the following effects on concurrently administered warfarin is most likely?
A. Increased anticoagulant effect and higher INR
B.Reduced anticoagulant effect and lower INR
C. No effect due to pharmacodynamic independence
D. Rapid onset of serotonin syndrome
Reduced anticoagulant effect and lower INR
A patient drinking grapefruit juice daily while taking a CYP3A4 substrate is at risk for which of the following?
A. Reduced drug efficacy due to enzyme induction
B. Enhanced drug clearance through biliary excretion
C. Increased drug toxicity due to reduced metabolism
D. Enhanced first-pass metabolism and drug inactivation
Increased drug toxicity due to reduced metabolism
what enhances the affects of warfarin?
a. low vitamin K
b. CYP3A4 ensyme
c. grapefruit juice
low vitamin K and grapefruit juice (grapefruit juice decreases cyp3a4 functions, increasing warfarin effects)
what inhibits the function of CYP3A4?
grapefruit juicy
why is
