Which of the following statements is correct about buspirone?

Correct Answer: D

Rationale: Buspirone is a unique anxiolytic medication with distinct pharmacological properties. The correct answer is D: "It has anxiolytic but no anticonvulsant or muscle relaxant property." This statement is correct because buspirone primarily acts as a partial agonist at serotonin receptors, specifically targeting the 5-HT1A receptors to exert its anxiolytic effects. Unlike benzodiazepines, it does not bind to GABA receptors, hence lacks anticonvulsant or muscle relaxant properties. Option A is incorrect because buspirone does not interact with benzodiazepine receptors, nor does it act as an inverse agonist. This is crucial to differentiate buspirone from benzodiazepines in terms of mechanism of action and potential side effects. Option B is incorrect as buspirone is not a rapidly acting anxiolytic. It typically takes 1-2 weeks of regular dosing to achieve therapeutic effects, making it unsuitable for managing acute panic states. Option C is incorrect as buspirone does not produce physical dependence or suppress barbiturate withdrawal syndrome. This is another crucial distinction from benzodiazepines, which are known to cause dependence and withdrawal symptoms upon discontinuation. Educationally, understanding the pharmacological profile of buspirone is essential for healthcare professionals to make informed decisions when prescribing anxiolytic medications. This knowledge helps in selecting the most appropriate treatment for patients based on their individual needs, comorbidities, and potential drug interactions.

Correct Answer: C

Rationale: Digitalis is a medication commonly used in the treatment of heart conditions like heart failure and certain arrhythmias. One of its key effects is to increase the refractory period of myocardial fibers, which refers to the period of time during which the cardiac muscle cells are unable to respond to a new stimulus. In the context of this question, the correct answer is C) A-V node. The atrioventricular (A-V) node is a critical part of the heart's conduction system that helps coordinate the electrical signals between the atria and ventricles. Digitalis-induced increase in refractory period in the A-V node is significant because it slows down the conduction of electrical impulses from the atria to the ventricles, ultimately leading to a decreased heart rate. Option A) Atria is incorrect because while digitalis can affect the atrial refractory period, its impact on the A-V node is more pronounced due to the node's critical role in regulating heart rate. Option B) Ventricles is incorrect because digitalis primarily affects the atrioventricular conduction system rather than the ventricles directly. Option D) Purkinje fibers is incorrect because digitalis-induced changes in refractory period are more noticeable in the A-V node due to its specific function in controlling the conduction of electrical impulses between the atria and ventricles. Understanding the effects of medications on the heart's conduction system is crucial for healthcare professionals, especially those involved in managing patients with cardiac conditions. Recognizing how digitalis affects different parts of the heart can help optimize treatment strategies and prevent potential complications.

Correct Answer: A

Rationale: The most suitable antiarrhythmic drug for counteracting ventricular extrasystoles due to digoxin toxicity is Lidocaine (Option A). Lidocaine is a Class IB antiarrhythmic drug that specifically targets ventricular arrhythmias, making it an appropriate choice for ventricular extrasystoles seen in digoxin toxicity. Quinidine (Option B) is a Class IA antiarrhythmic drug that is more effective for supraventricular arrhythmias and may exacerbate digoxin toxicity due to its interaction with digoxin levels. Verapamil (Option C) is a calcium channel blocker that is not typically used for ventricular arrhythmias and would not be the first choice for digoxin toxicity-related ventricular extrasystoles. Amiodarone (Option D) is a Class III antiarrhythmic drug that is effective for both supraventricular and ventricular arrhythmias but is not the drug of choice for ventricular extrasystoles specifically related to digoxin toxicity. In an educational context, understanding the mechanisms of action and specific indications of antiarrhythmic drugs is crucial for safe and effective pharmacological management of arrhythmias. This scenario highlights the importance of selecting the most appropriate drug based on the underlying cause of the arrhythmia to optimize patient outcomes and minimize adverse effects.

Correct Answer: B

Rationale: In the treatment of hypertension, beta-adrenergic blockers like propranolol, metoprolol, and atenolol have a significant advantage in that they do not cause postural hypotension, which is a sudden drop in blood pressure upon standing up. This is because beta blockers primarily work by reducing the heart rate and cardiac output, rather than dilating blood vessels. Option A is incorrect because beta blockers can indeed have side effects that impact work capacity, sleep quality, and libido. They can cause fatigue, insomnia, and sexual dysfunction in some individuals. Option C is incorrect because beta blockers do not have a high-ceiling antihypertensive efficacy when used alone. Their effectiveness may plateau at higher doses, limiting their ability to lower blood pressure further. Option D is incorrect because beta blockers are not always suitable for combination therapy with any other antihypertensive drug. For example, combining beta blockers with calcium channel blockers can lead to additive effects on heart rate and cardiac function, necessitating caution and monitoring. In an educational context, understanding the advantages and limitations of beta blockers in hypertension treatment is crucial for healthcare professionals to make informed decisions when managing patients with high blood pressure. It is essential to consider individual patient factors, comorbidities, and potential drug interactions when selecting the most appropriate antihypertensive therapy.

Correct Answer: B

Rationale: In the case of a woman in the 28th week of pregnancy with pregnancy-induced hypertension (BP 150/95 mmHg), the most appropriate drug for her to receive is Methyldopa (Option B). Methyldopa is considered the first-line treatment for hypertension in pregnancy due to its proven safety profile for both the mother and the developing fetus. It is a centrally acting alpha-2 adrenergic agonist that helps lower blood pressure without negatively impacting the pregnancy. Furosemide (Option A) is a diuretic that is contraindicated in pregnancy as it can lead to electrolyte imbalances and reduced placental perfusion, potentially harming the fetus. Propranolol (Option C) is a beta-blocker that can cause fetal growth restriction, bradycardia, and hypoglycemia, making it unsuitable for use in pregnancy. Captopril (Option D) is an ACE inhibitor that is contraindicated in pregnancy due to its association with fetal renal damage, hypotension, and even fetal death. Educationally, this question highlights the importance of selecting appropriate medications for pregnant patients, considering not only the efficacy for the mother but also the safety for the developing fetus. It underscores the need for healthcare providers to have a solid understanding of pharmacology in pregnancy to make informed and safe treatment decisions.