Drug to Drug Interactions

Question 1

What are drug interactions?

Answer 1

a situation in which a substance affects the activity of a drug.

Question 2

What type of effects can drug interactions lead to?

Answer 2

Question 3

What percent of hospital admissions are caused by drug interactions?

Answer 3

2.8%

Question 4

What age groups uses alot of drugs?

Answer 4

Above age 65(Frail elderly, hospitalized patients, and nursing home residents)

Question 5

What is a interaction between two drugs called and what is one example?

Answer 5

Drug-Drug Interaction (DDI)

Example: Between two drugs metabolized by the same CYP isoform - Estrogen, Rifampin

Question 6

What is an interaction with a drug and food called and what is one example?

Answer 6

Drug - Food Interactions

Example: Drugs metabolized by CYP enzymes and grapefruit juice.

Question 7

What is an interaction between a drug and a herb called and what is one example?

Answer 7

Drug-Herb Interactions

Example: Drugs metabolized by CYP and st Johns Wort

Question 8

What do diuretic drugs excrete?

Answer 8

Electrolytes

Question 9

What is a Pharmacodynamic Drug Interaction?

Answer 9

Two drugs affecting the same system.

Question 10

What is a Pharmakinetic Drug Interaction?

Answer 10

One drug changes the absorption, distribution, metabolism, excretion.

Question 11

What are some examples of DDI in Absorption?

Answer 11

• antacids reduce absorptions of tetracycline(Antibiotic)
• Calcium supplements reduce absorption of thyroxine(hormone)

Question 12

What are some examples of DDI in Distribution?

Answer 12

Competition for plasma protein binding by non-steroidal anti-inflammatory drugs(NSAIDS) and warfarin (anticoagulant) - Increase free concentration of the other drug.

Question 13

What are some examples of DDI of Excretion?

Answer 13

Probenecid reduces excretion of penicillin by competition for the kidney tubule transport system?

Question 14

What are some examples of DDI?

Answer 14

Two drugs metabolized by the same enzyme can compete for the enzyme CYP3A4

Question 15

What happens in liver and kidney disease?

Answer 15

Metabolism, Excretion, and Plasma levels of many drugs.

Question 16

What is the clinical significance of Drug - Drug interactions?

Answer 16

• When a patient is taking 2 or more drugs - consider drug interaction from metabolism
• When taking 1 drug metabolized by CYP - interactions with food and herbs should be considered.
• In cases of drug toxicicity or failure, consider gene morphisms or metabolizing enzymes