The unwanted effect of dihydrotachysterol is:

Correct Answer: B

Rationale: Step-by-step rationale: 1. Dihydrotachysterol is a form of vitamin D used to treat hypoparathyroidism. 2. Anorexia is a common unwanted effect due to increased calcium absorption causing decreased appetite. 3. Tetany is incorrect as vitamin D helps maintain calcium levels to prevent tetany. 4. CNS toxicity is incorrect as dihydrotachysterol does not typically affect the central nervous system. 5. Lymphocytopenia is incorrect as it is not a known side effect of dihydrotachysterol. Summary: The correct answer is B because anorexia is a common unwanted effect of dihydrotachysterol due to increased calcium absorption, while the other choices are incorrect as they do not align with the mechanism of action or known side effects of this medication.

Correct Answer: B

Rationale: The correct answer is B: Rifampin. Rifampin inhibits bacterial RNA synthesis by binding to the bacterial RNA polymerase enzyme. This prevents transcription of bacterial RNA, leading to inhibition of bacterial growth. Erythromycin (A) inhibits protein synthesis, Chloramphenicol (C) inhibits the peptidyl transferase activity during protein synthesis, and Imipinem (D) is a β-lactam antibiotic that inhibits bacterial cell wall synthesis. Thus, only Rifampin specifically targets bacterial RNA synthesis among the given choices.

Correct Answer: B

Rationale: The correct answer is B: Hepatotoxicity, peripheral neuropathy. Isoniazid is a commonly used medication for tuberculosis treatment. Hepatotoxicity is a well-known side effect, which can manifest as hepatitis or liver damage. Peripheral neuropathy is another common side effect, characterized by numbness, tingling, or burning sensations in the extremities. These effects are due to the drug's metabolism in the liver and its interference with nerve function. Choice A is incorrect as cardiotoxicity is not a known side effect of isoniazid. Choice C, loss of hair, is not a commonly reported side effect of isoniazid. Choice D, immunotoxicity, is not a major side effect associated with isoniazid use.

Correct Answer: B

Rationale: Step 1: Identify the conditions - ascaridosis and enterobiosis are caused by roundworms and pinworms, respectively. Step 2: Understand mechanism - Pyrantel works by paralyzing the worms, leading to expulsion from the body. Step 3: Specificity - Pyrantel is effective against both roundworms and pinworms. Step 4: Safety - Pyrantel is considered safe for use in treating these infections. Summary: A: Bithionol - used for tapeworm infections, not effective for roundworms or pinworms. C: Praziquantel - effective against tapeworms and flukes, not roundworms or pinworms. D: Suramin - used for African sleeping sickness, not indicated for ascaridosis or enterobiosis.

Correct Answer: D

Rationale: The correct answer is D: Decreased reabsorption of Ca2+ in the loop of Henle. Furosemide is a loop diuretic that inhibits the Na+/K+/2Cl- co-transporter in the thick ascending limb of the loop of Henle, leading to decreased reabsorption of Na+ and Ca2+. This leads to an increase in the excretion of Ca2+ in the urine, resulting in metabolic alkalosis due to loss of H+ ions in exchange for Na+ and Ca2+. A: Increased reabsorption of uric acid is not directly related to furosemide-induced metabolic alkalosis. B: Increased delivery of Na+ to the distal tubule would lead to increased reabsorption of Na+ and water, which would not result in metabolic alkalosis. C: Mild inhibition of carbonic anhydrase would not directly cause furosemide-induced metabolic alkalosis.