Which of the following is not a side effect associated with Prednisone toxicity?

Correct Answer: B

Rationale: The correct answer is B: Hypotension. Prednisone toxicity typically causes hypertension, not hypotension. Prednisone can lead to increased blood pressure due to its sodium-retaining effects. Cataracts (A), Psychosis (C), and Acne (D) are all known side effects of Prednisone toxicity. Cataracts can form due to long-term steroid use, psychosis can occur especially at higher doses, and acne is a common skin side effect. Therefore, hypotension is the odd one out among the choices given.

Correct Answer: D

Rationale: The correct answer is D: Procainamide. Procainamide is a class IA antiarrhythmic drug that blocks sodium channels, prolonging the action potential duration. This helps to stabilize the heart's rhythm. Mexiletine (A) is a class IB antiarrhythmic drug that blocks sodium channels with fast recovery kinetics. Amiodarone (B) is a class III antiarrhythmic drug that prolongs repolarization by blocking potassium channels. Quinidine (C) is a class IA antiarrhythmic drug that also blocks sodium channels, but it is not a class IB sodium channel blocker like Procainamide.

Correct Answer: A

Rationale: The correct answer is A: Quinidine. Quinidine is a class IA antiarrhythmic drug that blocks sodium channels in a use-dependent manner, which means it preferentially blocks channels that are open or have a rapid firing rate during depolarization. This action results in a decrease in conduction velocity and refractory period. Disopyramide is a class IA antiarrhythmic but does not specifically block sodium channels. Amiodarone is a class III antiarrhythmic that primarily affects potassium channels. Propafenone is a class IC antiarrhythmic that has minimal effects on sodium channel blockade. Therefore, Quinidine is the correct choice as a class IA sodium channel blocker.

Correct Answer: D

Rationale: The correct answer is D: Distal convoluted tubule. Potassium-sparing diuretics, such as spironolactone, act on the distal convoluted tubule by blocking the aldosterone receptor, which leads to decreased sodium reabsorption and potassium retention. This mechanism helps to promote diuresis while preventing potassium loss. Choices A, B, and C are incorrect because potassium-sparing diuretics do not primarily affect the proximal convoluted tubule, loop of Henle, or collecting duct in the kidney.

Correct Answer: D

Rationale: The correct answer is D: Projectile vomiting. Nitroglycerin is not directly associated with causing projectile vomiting. Nitroglycerin commonly causes headaches due to vasodilation, tachycardia due to decreased preload, and dizziness due to hypotension. Projectile vomiting is not a typical side effect of Nitroglycerin toxicity.