Minimal duration of antibacterial treatment usually is:

Correct Answer: C

Rationale: In pharmacology, determining the duration of antibacterial treatment is crucial to ensure effective therapy and prevent antibiotic resistance. The correct answer, option C (Not less than 10-14 days), is typically associated with treating bacterial infections adequately. The rationale behind this lies in the principles of pharmacokinetics and pharmacodynamics. Antibiotics need to be present in the body at a sufficient concentration for a certain duration to effectively kill bacteria and prevent the development of resistance. For most bacterial infections, a treatment duration of 10-14 days ensures that all bacteria are eradicated, reducing the risk of relapse or resistance. Options A, B, and D are incorrect because they do not provide a duration long enough to completely eradicate the bacterial infection. Antibiotics require a certain duration to act on bacteria, and premature discontinuation can lead to treatment failure, recurrent infections, and the development of antibiotic-resistant strains. Educationally, understanding the appropriate duration of antibiotic treatment is crucial for healthcare professionals to make informed decisions in clinical practice. It highlights the importance of following evidence-based guidelines to optimize patient outcomes and minimize the growing concern of antibiotic resistance. By grasping these concepts, students and practitioners can contribute to effective antibiotic stewardship and combat the global issue of antimicrobial resistance.

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: In the context of pharmacology, understanding the mechanisms of action of different drugs is crucial for safe and effective patient care. In this question about cardiovascular drugs, the correct answer is A) Fluorouracil, which is an anticancer drug and a pyrimidine antagonist. Fluorouracil works by inhibiting thymidylate synthase, an enzyme involved in DNA synthesis, thereby interfering with cancer cell growth. Option B) Mercaptopurine and Option C) Thioguanine are both purine analogs used in the treatment of leukemia. They work by interfering with the synthesis of DNA and RNA, not by acting as pyrimidine antagonists. Option D) Methotrexate is a folate antagonist commonly used in the treatment of cancer, autoimmune diseases, and ectopic pregnancies. Methotrexate inhibits dihydrofolate reductase, a key enzyme in the synthesis of purines and pyrimidines, but it is not specifically a pyrimidine antagonist like Fluorouracil. Understanding the specific mechanisms of action of different drugs is essential for pharmacology students and healthcare professionals to make informed decisions regarding drug therapy and patient care. By knowing the actions and indications of various drugs, healthcare providers can optimize treatment outcomes and minimize potential adverse effects.

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.