Tick the drug, inhibiting viral DNA synthesis:

Correct Answer: D

Rationale: The correct answer is D: Acyclovir. Acyclovir is a nucleoside analogue that inhibits viral DNA synthesis by acting as a chain terminator when incorporated into the viral DNA. Interferon (A) boosts the immune response, Saquinavir (B) inhibits HIV protease, and Amantadine (C) blocks viral entry. Therefore, only Acyclovir directly targets viral DNA synthesis.

Correct Answer: A

Rationale: The correct answer is A: Isosorbide mononitrate and nifedipine. Isosorbide mononitrate dilates coronary arteries, reducing myocardial oxygen demand. Nifedipine is a calcium channel blocker that helps reduce cardiac workload. Together, they can help manage symptoms of hypertrophic cardiomyopathy. Choice B (Nitroglycerin and captopril) is incorrect because captopril is an ACE inhibitor used for heart failure, not hypertrophic cardiomyopathy. Choice C (Nitroglycerin and verapamil) is incorrect because verapamil can worsen symptoms due to its negative inotropic effects. Choice D (Verapamil and metoprolol) is incorrect because metoprolol is a beta-blocker, which can worsen symptoms in hypertrophic cardiomyopathy by reducing heart rate and contractility.

Correct Answer: B

Rationale: In this question, the correct answer is B) Metoprolol. Metoprolol is a beta-blocker that is useful in angina by reducing the heart rate and blood pressure, thus decreasing the workload of the heart. It does not possess vasodilator properties but works by improving the oxygen supply-demand balance of the heart. Option A) Isosorbide dinitrate and option D) Nitroglycerin are both vasodilators commonly used in angina to dilate blood vessels, reduce the workload on the heart, and improve blood flow to the heart muscle. Option C) Nifedipine is a calcium channel blocker that also works by dilating blood vessels and reducing the workload on the heart. In an educational context, understanding the mechanisms of action of different cardiovascular medications is crucial for healthcare professionals to make informed decisions in patient care. Knowing which drugs have vasodilator properties and which do not is essential in selecting the most appropriate treatment for patients with angina. This knowledge helps in optimizing therapy, managing drug interactions, and preventing potential adverse effects.

Correct Answer: A

Rationale: Levonordefrin is primarily used to treat shock due to its potent vasoconstrictive properties, making it effective in increasing blood pressure and restoring perfusion to vital organs in cases of severe hypotension. In the context of shock, levoarterenol acts by stimulating alpha-1 adrenergic receptors, leading to peripheral vasoconstriction and subsequent elevation of blood pressure. Diabetes (Option B) is not a primary indication for levoarterenol use. In fact, caution is warranted in diabetic patients due to the potential for worsening hyperglycemia as a result of its adrenergic effects. Hypertension (Option C) is not a typical indication for levoarterenol use as it can exacerbate hypertension due to its vasoconstrictive properties. Cardiac arrhythmias (Option D) are not treated with levoarterenol as it can potentially worsen arrhythmias due to its adrenergic effects on the heart. Educationally, understanding the specific indications for cardiovascular drugs like levoarterenol is crucial for healthcare professionals to ensure safe and effective patient care. Knowledge of drug interactions, contraindications, and appropriate use is fundamental in the management of cardiovascular conditions and emergencies.

Correct Answer: D

Rationale: The correct answer is D) Its half-life is more dependent on the adequacy of renal function. Digoxin and digitoxin are both cardiac glycosides used in the treatment of heart conditions like heart failure and atrial fibrillation. Digoxin differs from digitoxin in terms of its pharmacokinetic properties. Digoxin has a shorter half-life compared to digitoxin, and its elimination is highly dependent on renal function. This means that in patients with impaired renal function, the half-life of digoxin can be significantly prolonged, leading to potential toxicity if not properly monitored and adjusted. Now let's analyze why the other options are incorrect: A) Has a longer half-life - This is incorrect as digoxin actually has a shorter half-life compared to digitoxin. B) Is completely absorbed from the GI tract - This is incorrect as digoxin is not completely absorbed from the GI tract, and its absorption can be affected by various factors. C) Is bound extensively to plasma proteins - While digoxin is bound to plasma proteins, this is not the key difference between digoxin and digitoxin. Understanding the differences between digoxin and digitoxin in terms of pharmacokinetics is crucial for healthcare professionals managing patients on these medications. It highlights the importance of monitoring renal function and adjusting dosages accordingly to prevent toxicity and ensure therapeutic effectiveness. This knowledge is essential for safe and effective medication management in patients with cardiac conditions.