Tick the antimalarial drug influencing tissue schisonts:

Correct Answer: D

Rationale: In this question, the correct answer is option D) Primaquine. Primaquine is an antimalarial drug that influences tissue schizonts, which are the replicating forms of the malaria parasite found in the liver. Primaquine is particularly effective against the liver stages of malaria parasites, including Plasmodium vivax and Plasmodium ovale. Option A) Mefloquine is primarily used for the treatment and prevention of malaria caused by Plasmodium falciparum and Plasmodium vivax but does not target tissue schizonts specifically. Option B) Chloroquine is effective against the erythrocytic stages of malaria parasites but does not target tissue schizonts in the liver. Option C) Quinidine is used in the treatment of severe malaria caused by Plasmodium falciparum but does not have a specific action on tissue schizonts. Understanding the mechanisms of action and specific targets of antimalarial drugs is crucial in pharmacology to ensure appropriate treatment selection and efficacy. By grasping the unique characteristics of each drug, healthcare professionals can make informed decisions in managing malaria cases effectively.

Correct Answer: A

Rationale: The correct answer is A) Thiazides enhance the antihypertensive effect of losartan. This combination therapy is commonly used in the management of hypertension due to their complementary mechanisms of action. Hydrochlorothiazide, a thiazide diuretic, works by reducing blood volume and cardiac output, leading to decreased blood pressure. Losartan, an angiotensin II receptor blocker, acts by dilating blood vessels, reducing blood pressure, and protecting the heart from the harmful effects of angiotensin II. When used together, thiazides like hydrochlorothiazide can enhance the antihypertensive effect of losartan by reducing fluid volume and decreasing peripheral resistance, thus improving blood pressure control. This synergy allows for lower doses of each drug to be used, minimizing side effects and improving overall efficacy. Option B is incorrect because losartan does not counteract thiazide-induced hypercalcemia; in fact, thiazides can lead to hypocalcemia, not hypercalcemia. Option C is incorrect as thiazides do not inhibit the appearance of tolerance to losartan, but rather, they can enhance its effectiveness. Option D is incorrect as age alone does not determine the response to losartan, and many individuals over 65 can benefit from this medication, especially when used in combination with other antihypertensive agents. Understanding the rationale behind combination therapy in hypertension management is crucial for healthcare professionals to make informed decisions when selecting the most appropriate treatment for patients. It highlights the importance of considering the mechanisms of action of different drug classes and how they can work synergistically to achieve optimal therapeutic outcomes while minimizing adverse effects.

Correct Answer: A

Rationale: Severe postural hypotension is a common adverse effect of drugs that decrease central sympathetic outflow, such as alpha blockers like Hydralazine. This can lead to a sudden drop in blood pressure when standing up, causing symptoms like dizziness and fainting. Megaloblastic anemia is associated with folate deficiency, Palpitations are irregular heartbeats, and Pronounced sedation is excessive drowsiness, none of which are typically associated with this mechanism of action.

Correct Answer: C

Rationale: In this scenario, the correct thrombolytic agent to use is option C) Recombinant tissue-type plasminogen activator (t-PA). Tissue plasminogen activators like t-PA are preferred over streptokinase-based agents due to their higher specificity for fibrin-bound plasminogen, which leads to localized clot lysis and reduced systemic activation of plasmin. This specificity reduces the risk of bleeding complications associated with non-fibrin-specific agents like streptokinase. Option A) Anisoylated plasminogen streptokinase activator complex (APSAC) is not commonly used anymore due to its association with increased allergic reactions. Option B) Streptokinase (SK) is less specific than t-PA and can lead to more systemic plasmin activation, increasing the risk of bleeding complications. Educationally, understanding the differences in thrombolytic agents is crucial for healthcare providers to make informed decisions in managing patients with thrombotic disorders. By knowing the mechanism of action, indications, contraindications, and potential side effects of each agent, healthcare professionals can tailor treatment to individual patients, optimizing outcomes while minimizing risks.

Correct Answer: D

Rationale: In the treatment of angina pectoris, the concurrent use of nitrates and calcium channel blockers is beneficial due to their complementary mechanisms of action. Nitrates primarily reduce preload by dilating veins, which decreases the amount of blood returning to the heart and subsequently reduces the workload on the heart. On the other hand, calcium channel blockers predominantly reduce afterload by dilating arterioles, which decreases systemic vascular resistance and the workload on the heart. By combining these two classes of drugs, both preload and afterload are reduced, resulting in a more comprehensive relief of angina symptoms. Option A is incorrect because nitrates and calcium channel blockers do not antagonize each other's side effects but rather work synergistically to improve angina symptoms. Option C is incorrect as nitrates primarily increase coronary flow by dilating coronary arteries, while calcium channel blockers do not have a direct effect on coronary flow. Educationally, understanding the rationale behind combining nitrates and calcium channel blockers in angina treatment is crucial for healthcare professionals to optimize patient care. By comprehensively addressing both preload and afterload, this combination therapy provides more effective symptom relief and can improve the quality of life for patients with angina. This knowledge is essential for pharmacology students and healthcare providers to make informed decisions in managing cardiovascular conditions.