Author Question: What is the action of a drug antagonist? 1. It facilitates cell action. 2. It does not bind with ... (Read 78 times)

codyclark · **on:** Jul 24, 2018

What is the action of a drug antagonist?

1. It facilitates cell action.
2. It does not bind with receptors.
3. It blocks the actions of an agonist.
4. It has no therapeutic benefit.

Question 2

Codeine has a greater maximal ability to suppress cough when compared with dextromethorphan. What is the most appropriate description of codeine when compared to dextromethorphan?

1. Codeine is more efficacious.
2. Codeine is less potent.
3. Codeine is more potent.
4. Codeine is less efficacious.

zenzy · **Reply #1 on:** Jul 24, 2018

Answer to Question 1

Correct Answer: 3

Rationale 1: Agonists facilitate drug action; antagonists block the effects of agonists.
Rationale 2: Many therapeutically useful drugs act by blocking receptors (e.g., beta-adrenergic blockers, antihistamines).
Rationale 3: Blocks the actions of an agonist is the definition of an antagonist.
Rationale 4: Many therapeutically useful drugs act by blocking receptors (e.g., beta-adrenergic blockers, antihistamines).

Global Rationale: Blocks the actions of an agonist is the definition of an antagonist. An agonist facilitates drug action. Many therapeutically useful drugs act by blocking receptors (e.g., beta-adrenergic blockers, antihistamines); therefore, not biding with receptors and it has no therapeutic effect are both incorrect.

Answer to Question 2

Correct Answer: A

Rationale 1: Codeine has a greater maximal effect than dextromethorphan; it is more efficacious than is dextromethorphan.
Rationale 2: Less potent is incorrect because potency refers to the dosage of drug required to produce a certain magnitude of response, whereas efficacy is the magnitude of the maximum response to a drug.
Rationale 3: More potent is incorrect because potency refers to the dosage of drug required to produce a certain magnitude of response, whereas efficacy is the magnitude of the maximum response to a drug.
Rationale 4: Less efficacious is incorrect; because codeine has a greater maximal effect than does dextromethorphan, it is more efficacious than is dextromethorphan.

Global Rationale: Codeine has a greater maximal effect than dextromethorphan; it is more efficacious than is dextromethorphan. Less potent is incorrect because potency refers to the dosage of drug required to produce a certain magnitude of response, whereas efficacy is the magnitude of the maximum response to a drug. More potent is incorrect because potency refers to the dosage of drug required to produce a certain magnitude of response, whereas efficacy is the magnitude of the maximum response to a drug. Less efficacious is incorrect; because codeine has a greater maximal effect than does dextromethorphan, it is more efficacious than is dextromethorphan.