Tick the drug used for HIV infection treatment, a derivative of nucleosides:

Correct Answer: B

Rationale: The correct answer is B: Zidovudine. Zidovudine is a nucleoside analog reverse transcriptase inhibitor used in the treatment of HIV infection. It works by inhibiting the reverse transcriptase enzyme, crucial for viral replication. Acyclovir (A) is used for herpes infections, Gancyclovir (C) for cytomegalovirus, and Trifluridine (D) for ocular herpes. They are not derivatives of nucleosides and are not used for HIV treatment.

Correct Answer: B

Rationale: The correct answer is B: Amiodarone. Amiodarone is the most appropriate choice because it is a Class III antiarrhythmic drug that is effective in treating various types of arrhythmias, including ventricular and atrial arrhythmias. It works by prolonging the action potential duration and refractory period of cardiac tissue, helping to stabilize the heart's rhythm. Quinidine (A) is a Class I antiarrhythmic drug with potential side effects and limited efficacy. Verapamil (C) is a calcium channel blocker that is more suitable for treating certain types of supraventricular arrhythmias but not as effective for other types. Propranolol (D) is a beta-blocker that may be used for certain arrhythmias, but it is not as effective or versatile as amiodarone for treating various types of arrhythmias.

Correct Answer: C

Rationale: In this question, the correct answer is C) Spironolactone. Spironolactone is a potassium-sparing diuretic that works by inhibiting the action of aldosterone, a hormone that regulates sodium and potassium balance in the body. By blocking aldosterone, spironolactone helps the kidneys retain potassium and excrete sodium and water, leading to diuresis while preventing potassium loss. Option A) Amiloride and option B) Triamterene are also potassium-sparing diuretics, but they work by directly blocking sodium channels in the distal tubule rather than inhibiting aldosterone. Therefore, they do not specifically target aldosterone action like spironolactone does. The educational context here is crucial for understanding the mechanisms of action of different diuretics and their specific targets in the body. Understanding how each drug works helps healthcare professionals make informed decisions when prescribing medications for patients with cardiovascular conditions or hypertension. It is essential for healthcare providers to have a solid grasp of pharmacology to ensure safe and effective patient care.

Correct Answer: D

Rationale: In the context of drugs affecting the cardiovascular system, the correct answer for the termination of paroxysmal supraventricular tachycardia is Verapamil (Option D). Verapamil is a calcium channel blocker that acts on the AV node to slow conduction, making it effective in terminating re-entrant supraventricular tachycardias like paroxysmal supraventricular tachycardia (PSVT). Digoxin (Option A) is primarily used for heart failure and atrial fibrillation but is not the drug of choice for terminating PSVT. Quinidine (Option B) is a class I antiarrhythmic agent that can be proarrhythmic and is not commonly used for PSVT termination. Propranolol (Option C) is a beta-blocker that can slow heart rate but is not as effective as Verapamil in terminating PSVT due to its mechanism of action. In an educational context, understanding the mechanism of action of different drugs is crucial in selecting the most appropriate treatment for specific cardiovascular conditions. Verapamil's specific action on the AV node and its efficacy in terminating PSVT make it the preferred choice in this scenario, highlighting the importance of drug selection based on mechanism of action and desired outcomes in clinical practice.

Correct Answer: B

Rationale: Verapamil is a calcium channel blocker used in the treatment of various cardiovascular conditions like hypertension, angina, and arrhythmias. The correct dose of verapamil is 40 to 80 mg thrice daily. Explanation of why B is the correct answer: Verapamil is typically prescribed in doses ranging from 40 to 80 mg taken three times a day. This dosing regimen helps maintain a consistent level of the medication in the bloodstream to effectively manage cardiovascular conditions like hypertension and angina. Taking verapamil three times a day ensures that the drug's therapeutic effects are sustained throughout the day. Explanation of why the other options are wrong: A) 4 to 6 gms per day: This dose is excessively high and could lead to serious overdose symptoms and adverse effects. C) 1 to 10 mg thrice daily: This dose range is too low to achieve the desired therapeutic effect of verapamil in managing cardiovascular conditions. D) 250 mg once daily: This dose is insufficient to provide adequate coverage throughout the day for conditions requiring multiple daily doses of verapamil. Educational context: Understanding the correct dosage of medications is crucial for healthcare professionals to ensure patient safety and optimal treatment outcomes. In the case of verapamil, knowing the appropriate dose range and dosing frequency is essential to effectively manage cardiovascular conditions. Healthcare providers must be knowledgeable about medication dosages to prevent errors that could harm patients.