Which of the following drugs is a selective serotonin reuptake inhibitor (SSRI) used to treat depression?

Correct Answer: A

Rationale: The correct answer is A: Fluoxetine. Fluoxetine is a selective serotonin reuptake inhibitor (SSRI) commonly used to treat depression by increasing serotonin levels in the brain. This drug specifically targets the reuptake of serotonin, leading to higher levels available in the brain to improve mood. Choice B: Amitriptyline is a tricyclic antidepressant, not an SSRI, and works by affecting the balance of certain neurotransmitters in the brain. Choice C: Sertraline is another SSRI used for depression, but it is not the correct answer in this case. Choice D: Mirtazapine is a different class of antidepressant called a noradrenergic and specific serotonergic antidepressant (NaSSA), not an SSRI. Therefore, the correct choice is A, Fluoxetine, as it is the only SSRI listed among the options provided.

Correct Answer: A

Rationale: The correct answer is A: Blocking aldosterone receptors. Spironolactone is a potassium-sparing diuretic that works by blocking aldosterone receptors in the distal convoluted tubules of the kidneys. By inhibiting aldosterone, spironolactone reduces sodium and water retention, decreases potassium excretion, and helps reduce fluid overload in heart failure patients. Choices B, C, and D are incorrect because spironolactone does not directly increase sodium and water excretion in the kidneys, inhibit the action of angiotensin II, or block beta-1 adrenergic receptors in the heart.

Correct Answer: B

Rationale: The correct answer is B: Phosphodiesterase type 5 inhibitors (PDE5 inhibitors) are used for treating erectile dysfunction by increasing blood flow to the penis. Beta-blockers (A), ACE inhibitors (C), and diuretics (D) are not indicated for erectile dysfunction treatment as they do not target the underlying physiological mechanisms responsible for erectile function. PDE5 inhibitors specifically target the vasodilation process in the penis, leading to improved erectile function.

Correct Answer: A

Rationale: The correct answer is A: Osteoporosis. Proton pump inhibitors (PPIs) can inhibit calcium absorption, potentially leading to osteoporosis. PPIs reduce stomach acid production, increasing the risk of bone fractures. B: Gastritis is incorrect as PPIs are actually used to treat gastritis by reducing stomach acid. C: Weight loss is incorrect as PPIs are not associated with weight loss. D: Hypoglycemia is incorrect as PPIs do not affect blood sugar levels significantly.

Correct Answer: A

Rationale: The correct answer is A: Inhibiting the reabsorption of glucose in the kidneys. Canagliflozin is a sodium-glucose cotransporter-2 (SGLT2) inhibitor that works by blocking the reabsorption of glucose in the kidneys, leading to increased urinary glucose excretion and lowering blood glucose levels. This mechanism of action is unique to SGLT2 inhibitors and helps improve glycemic control in patients with type 2 diabetes. Choice B is incorrect because canagliflozin does not stimulate the pancreas to release more insulin. Choice C is incorrect as canagliflozin does not increase the release of glucagon from the pancreas. Choice D is incorrect because canagliflozin does not directly improve insulin sensitivity in peripheral tissues. The key mechanism of action of canagliflozin lies in its specific inhibition of glucose reabsorption in the kidneys, making choice A the correct answer.