Week 3: Efficacy and Potency

Question 1

What is efficacy of a drug?

Answer 1

How good the drug is at their job

Question 2

What is potency of a drug?

Answer 2

strength, how strong the drug is

Question 3

What is the relationship between drugs and receptors?

Answer 3

• drugs are chemicals that can only produce effects that are physiologic activities normally regulated by the body’s receptors
• they essentially mimic or stop what our bodies are doing

Question 4

What are agonists? (3)

Answer 4

• Mimic the action of endogenous (inside body) regulatory hormones
• partial agonists
  ex. Beta agonists (gas exchange drugs)

Question 5

What are antagonists?

Answer 5

• block/prevent the action of endogenous regulatory molecules
• non-competitive vs competitive
  ex. Beta blockers (perfusion drugs0

Question 6

What do non-competitive antagonist drugs do? (3)

Answer 6

• “plug the keyhole” irreversibly
• prevent drug from attaching
• ex. KETAMINE

Question 7

What do competitive antagonist drugs do? (2)

Answer 7

• compete with drugs at the keyhole and whichever has the highest concentration will attach
• reversible

Question 8

How is naloxone a competitive antagonist drug?

Answer 8

It blocks opioids until plasma concentration levels drop below opioid blood level
- repeat dose

Question 9

What are the four primary receptor families?

Answer 9

1. Cell membrane-embedded enzymes
2. Ligand-gated ion channels
3. G Protein-Coupled receptor systems
4. transcription factors

Question 10

What is the therapeutic INDEX?

Answer 10

• measure of a drug’s safety

Question 11

What does it mean if a drug has a small or narrow therapeutic index?

Answer 11

• unsafe or high risk for toxicity
• the smaller the number, the more dangerous
  ex. Phenytoin (dilantin) has a TI of 2

Question 12

Why is the therapeutic index important?

Answer 12

• we use this information to help predict drug interactions
• low TI are often monitored with lab tests

Question 13

What are inducers?

Answer 13

drugs that increase metabolism of other drugs

Question 14

What are inhibitors?

Answer 14

• drugs that decrease metabolism of other drugs

Question 15

Are OTC herbal supplements okay to use? (4)

Answer 15

• know benefits and risks
• safety
• medication review
• patient education

Question 16

What is altered absorption when it comes to drug and supplement interactions? (3)

Answer 16

• calcium containing foods can reduce absorption (milk products or calcium supplements)
• high fiber foods can reduce absorption
• High calorie meals can double absorption rate (HIV drugs)

Question 17

What is altered metabolism? (3)

Answer 17

• grapefruit juice inhibits metabolism by raising serum drug levels
• supplements
• herbal medicine

Question 18

When should you take drugs on an empty stomach? (3)

Answer 18

• if absorption is decreased
• 1 hour before meal
• or 2 hours after

Question 19

When should you take drugs with food? (2)

Answer 19

• if absorption increased
• if causes GI upset