A calcium channel blocker (CCB) is prescribed for a patient, and the nurse provides instructions to the patient about the medication. Which instruction is correct?

Correct Answer: D

Rationale: The correct answer is D: A high-fiber diet with plenty of fluids will help prevent the constipation that may occur. Rationale: 1. CCBs can cause constipation as a side effect due to their action on smooth muscle. 2. A high-fiber diet and adequate fluids help prevent constipation by promoting bowel regularity. 3. Increasing fiber intake can soften stool and facilitate passage, reducing the risk of constipation. 4. Adequate fluid intake is essential to maintain hydration and support digestive function, aiding in the prevention of constipation. Summary: A: Chewing the tablet may alter the drug's release mechanism and is not recommended for CCBs. B: Grapefruit juice can interact with CCBs, potentially increasing drug levels and side effects. C: Adverse effects like chest pain, fainting, or dyspnea may indicate a serious reaction, but immediate discontinuation should be done under medical guidance, not solely based on patient judgment.

Correct Answer: B

Rationale: The correct answer is B: Instruct the patient to take the medication through a plastic straw. This is because iron supplements can stain teeth, and using a straw can help minimize direct contact with teeth, reducing the risk of staining. A: Having the patient take the liquid iron with milk is incorrect as calcium in milk can interfere with iron absorption. C: Having the patient sip the medication slowly is not necessary for the administration of iron supplements. D: Having the patient drink the medication undiluted from the unit-dose cup increases the risk of teeth staining.

Correct Answer: C

Rationale: The correct answer is C because a receptor is a specific active macromolecular component of a cell or organism that a drug molecule must bind to in order to elicit a specific effect. This definition aligns with the concept of receptors in pharmacology. A is incorrect because ion channels are not necessarily receptors. B is incorrect because enzymes involved in oxidizing-reducing reactions are not typically considered receptors. D is incorrect because carriers are not the same as receptors in pharmacology. In summary, answer C is the most appropriate as it accurately defines the role of a receptor in pharmacology, while the other choices do not align with the definition of a receptor.

Correct Answer: D

Rationale: The correct answer is D because local anesthetics are usually made available as salts due to their greater water solubility and stability. Water-soluble salts are easier to dissolve and distribute in the body, enhancing their effectiveness. Additionally, the stability of salts ensures a longer shelf life and reduces the risk of degradation. Choices A, B, and C are incorrect because local anesthetics as salts do not necessarily lead to less toxicity, higher stability, greater lipid solubility, less local tissue damage, or more potency.

Correct Answer: C

Rationale: Physostigmine is the correct answer as it is a reversible cholinesterase inhibitor. This means it binds to the enzyme temporarily and can be easily displaced, allowing the enzyme to function normally after a while. Physostigmine is commonly used in the treatment of glaucoma and myasthenia gravis. A: Isoflurophate is an irreversible cholinesterase inhibitor, meaning it forms a permanent bond with the enzyme. B: Carbochol is a direct-acting cholinergic agonist, not a cholinesterase inhibitor. D: Parathion is an organophosphate insecticide that irreversibly inhibits cholinesterase enzymes.