Tick the antibacterial drug – a nitroimidazole derivative:

Correct Answer: B

Rationale: The correct answer is B: Metronidazole. Metronidazole is a nitroimidazole derivative commonly used as an antibacterial and antiprotozoal drug. It works by disrupting the DNA structure of bacteria and parasites, leading to their death. Clavulanic acid (A) is a beta-lactamase inhibitor, not an antibacterial drug. Nitrofurantoin (C) is a nitrofuran derivative used for urinary tract infections, not a nitroimidazole derivative. Doxycycline (D) is a tetracycline antibiotic, not a nitroimidazole derivative. Therefore, the correct choice is B as it is the only nitroimidazole derivative among the options provided.

Correct Answer: B

Rationale: The correct answer is B: Postural hypotension. Nitroglycerin and isosorbide mononitrate are vasodilators that can cause a sudden drop in blood pressure when standing up, leading to postural hypotension. This is especially risky in patients with exertional angina, as it can exacerbate symptoms. A: Cough and wheezing are not common side effects of nitroglycerin or isosorbide mononitrate. C: Reflex bradycardia is unlikely as these medications primarily affect blood vessels, not the heart rate. D: Methemoglobinemia is a rare side effect associated with certain medications but is not commonly seen with nitroglycerin or isosorbide mononitrate.

Correct Answer: B

Rationale: The correct answer is B: Reduction of angiotensin-mediated vasoconstriction in the kidney. Captopril is an ACE inhibitor that works by blocking the conversion of angiotensin I to angiotensin II. In this patient with systolic heart failure, reducing angiotensin II levels will lead to vasodilation and decreased vasoconstriction in the kidney, improving renal blood flow and reducing fluid retention. This helps to alleviate symptoms of heart failure and improve overall cardiac function. Incorrect choices: A: Increased cardiac contractility - Captopril does not directly increase cardiac contractility. C: Reduction of preload and afterload - While ACE inhibitors can reduce preload and afterload, the primary mechanism of captopril is through the renin-angiotensin-aldosterone system. D: Stimulation of epinephrine release from adrenergic nerves - Captopril does not stimulate epinephrine release; it actually inhibits the

Correct Answer: A

Rationale: The correct answer is A) Alprostadil. Alprostadil is a medication used in the treatment of male impotence (erectile dysfunction) by directly activating prostaglandin E1 receptors, leading to vasodilation and increased blood flow to the penis, thereby facilitating an erection. Option B) Fluoxetine is a selective serotonin reuptake inhibitor (SSRI) used primarily as an antidepressant and is not indicated for the treatment of male impotence. Option C) Mifepristone is a medication used for medical abortion in combination with misoprostol and is not used for male impotence. Option D) Sildenafil is a phosphodiesterase type 5 (PDE5) inhibitor used for the treatment of erectile dysfunction by enhancing the effects of nitric oxide, leading to vasodilation and improved blood flow to the penis. While both Alprostadil and Sildenafil are used in erectile dysfunction, the specific mechanism of action described in the question points to Alprostadil as the correct answer. Understanding the mechanisms of action of different drugs used in the treatment of male impotence is crucial for healthcare professionals to make informed decisions regarding the selection of appropriate medications for patients. This knowledge helps in providing effective and tailored treatment options based on individual patient needs and medical history.

Correct Answer: C

Rationale: Quinidine is a Class I antiarrhythmic drug that primarily works by blocking sodium channels in cardiac tissues. The correct answer to the question is C) Auricular fibrillation. Quinidine can cause paradoxical tachycardia in a patient with auricular fibrillation because it can lead to an increase in the ventricular rate by blocking the atrioventricular node, thereby allowing more rapid conduction of atrial impulses to the ventricles. Option A) Sick sinus syndrome is incorrect because quinidine is more likely to exacerbate bradycardia in patients with this condition rather than cause paradoxical tachycardia. Option B) Auricular extrasystoles is incorrect because quinidine is used to treat this condition rather than cause paradoxical tachycardia in patients with it. Option D) Ventricular extrasystoles is incorrect because quinidine typically does not cause paradoxical tachycardia in patients with this condition. Understanding the effects of quinidine on different cardiac conditions is crucial for healthcare professionals, especially pharmacists and physicians, to ensure safe and effective treatment of patients with arrhythmias. It is essential to recognize the potential paradoxical responses to antiarrhythmic drugs to avoid worsening the patient's condition.