Which of the following classes of medication decreases heart rate, contractility, and blood pressure, and is used to increase survival rates in post-myocardial infarction patients?

Explanation:

A. This is because lithium levels can be affected by changes in sodium balance and hydration levels in the body. Excessive sweating can lead to dehydration, which can increase lithium levels and potentially lead to toxicity. Therefore, it is important for clients to be aware of the need to maintain hydration and to communicate with their healthcare provider if there are any significant changes in their fluid balance, such as those caused by excessive sweating.

B. Stopping lithium abruptly, especially when moods are stable, can lead to relapse of bipolar disorder symptoms and is not recommended.

C. Regular monitoring of blood levels of lithium is essential to ensure therapeutic levels and prevent toxicity; therefore, the statement indicating the client no longer needs blood checks is incorrect.

D. Restricting salt intake lowers the sodium levels which can decrease lithium elimination, hence increasing the risk of toxicity.

Explanation:

A. Adequate hydration is important to prevent lithium toxicity; decreasing fluid intake is not recommended.

B. Constipation can slow the excretion of lithium and may increase the risk of toxicity, but it is not the most appropriate preventive measure.

C. Sudden changes in sodium intake can affect lithium levels, so restricting sodium-rich foods without medical advice is not advisable.

D. Clients should be cautious with physical activity in hot weather, as excessive sweating can lead to dehydration, increasing the risk of lithium toxicity.