The client has been prescribed an organic nitrate for angina. What affect does this class of drugs have on the heart?

Correct Answer: A

Rationale: The correct answer is A: Decreases preload. Organic nitrates dilate veins, reducing venous return to the heart and therefore decreasing preload. This helps to reduce the workload on the heart and improve oxygen supply to the myocardium. B: Increases afterload - Organic nitrates do not increase afterload. They actually reduce afterload by dilating arteries and reducing vascular resistance. C: Constricts arterioles - Organic nitrates mainly dilate both arteries and veins, causing vasodilation rather than arteriole constriction. D: Increases preload - Organic nitrates do the opposite by reducing preload through venous dilation.

Correct Answer: B

Rationale: The correct answer is B: It directly inhibits thrombin. Dabigatran (Pradaxa) is a direct thrombin inhibitor, preventing the conversion of fibrinogen to fibrin, thereby inhibiting the clotting cascade. This mechanism differs from antiplatelet drugs (A) that inhibit platelet aggregation, fibrinolytic medications (C) that dissolve existing clots, and drugs that interfere with clotting factors production (D) which is not the mechanism of action for dabigatran. By directly inhibiting thrombin, dabigatran has a more specific and targeted effect on the clotting process.

Correct Answer: C

Rationale: The correct answer is C: Antibody production against the streptokinase. Streptokinase is a foreign protein that the body may recognize as an antigen, leading to the production of antibodies. This can result in an allergic reaction or anaphylaxis. Pulmonary embolism (A) and acute myocardial infarction (B) are potential complications of a blood clot but not directly related to streptokinase use. Acute gastric irritation (D) is not a common adverse reaction to streptokinase.

Correct Answer: B

Rationale: The correct answer is B: It inhibits absorption of cholesterol in the small intestines. Zetia works by blocking the absorption of cholesterol in the small intestines, reducing the amount of cholesterol that enters the bloodstream. This mechanism helps lower LDL cholesterol levels. Choices A, C, and D are incorrect because Zetia does not affect cholesterol synthesis by the liver, increase LDL cholesterol production, or alter the ratio of HDL to LDL cholesterol.

Correct Answer: C

Rationale: The correct answer is C: Atrial depolarization. The P wave on an ECG represents the depolarization of the atria, indicating the contraction of the atria. This is the first electrical activity that occurs in the heart's conduction system. Ventricular depolarization (choice A) is represented by the QRS complex, while ventricular repolarization (choice B) is represented by the T wave. Atrial repolarization (choice D) is typically hidden within the QRS complex, making it difficult to identify on a standard ECG. Therefore, the P wave best represents atrial depolarization due to its timing and shape on the ECG waveform.