Correct Answer: A

Rationale: In this scenario, the client is experiencing severe hypotension due to Verapamil administration. The appropriate medication to counteract the vasodilation caused by Verapamil and reverse severe hypotension is Calcium gluconate, which should be administered slowly IV. Therefore, the correct choice is Calcium gluconate (Choice A).

Correct Answer: B

Rationale: Furosemide is a diuretic that commonly causes hyponatremia (low sodium levels) due to its effect on sodium and water excretion. The nurse must closely monitor the client for signs of hyponatremia, such as weakness, confusion, and muscle cramps, and promptly intervene to prevent complications.

Correct Answer: A

Rationale: St. John's wort should be avoided by clients taking Warfarin as it can reduce the medication's effectiveness. The nurse should also advise the client to avoid other supplements that may interact with Warfarin, such as garlic and ginseng.

Correct Answer: C

Rationale: Sucralfate can interfere with the absorption of phenytoin. To prevent this interaction, the client should allow a 2-hour interval between taking sucralfate and phenytoin. This interval helps ensure that each medication is absorbed effectively without affecting the other's absorption.

Correct Answer: B

Rationale: Coarse tremors are a common sign of Lithium toxicity. It is important for healthcare providers to monitor for this symptom as it indicates a potential overdose of the medication. Severe hypertension, constipation, and muscle spasms are not typically associated with Lithium toxicity.