Correct Answer: A

Rationale: Furosemide, a loop diuretic, can cause potassium loss. Clients should increase their intake of potassium-rich foods to prevent hypokalemia.

Correct Answer: D

Rationale: Activated partial thromboplastin time (aPTT) is the correct laboratory test to monitor while a client is receiving Heparin. This test is used to assess the therapeutic levels of heparin in the blood, ensuring that the dose is within the safe and effective range. Monitoring aPTT helps healthcare providers adjust the dosage of Heparin to prevent complications such as bleeding or clotting.

Correct Answer: C

Rationale: Metformin is commonly prescribed to manage and control blood glucose levels in individuals with diabetes. It helps in reducing the amount of glucose produced by the liver and improves the body's response to insulin, thereby aiding in the regulation of blood sugar levels. It is not used to lower blood pressure, diminish seizure activity, increase heart rate, or decrease gastrointestinal secretions.

Correct Answer: C

Rationale: Phenytoin is primarily used to diminish seizure activity and is effective in terminating ventricular arrhythmias. It works by stabilizing neuronal membranes, reducing repetitive neuronal firing, and limiting the spread of seizure activity in the brain. While phenytoin does not have a direct role in preventing thrombus formation or extending existing thrombi, it is crucial in managing seizures and certain arrhythmias.

Correct Answer: B

Rationale: The correct instruction for a client prescribed Trimethoprim-Sulfamethoxazole is to increase fluid intake. This helps prevent crystalluria and kidney stones, which are potential adverse effects of this medication. Adequate hydration is essential to reduce the risk of these complications.