Potassium-sparing diuretics primarily affect which part of the kidney?

Correct Answer: D

Rationale: The correct answer is D: Distal convoluted tubule. Potassium-sparing diuretics, such as spironolactone, act on the distal convoluted tubule by blocking the aldosterone receptor, which leads to decreased sodium reabsorption and potassium retention. This mechanism helps to promote diuresis while preventing potassium loss. Choices A, B, and C are incorrect because potassium-sparing diuretics do not primarily affect the proximal convoluted tubule, loop of Henle, or collecting duct in the kidney.

Correct Answer: B

Rationale: The correct answer is B: ACE inhibitor. Drugs ending in the suffix (-pril) typically refer to ACE inhibitors, which are commonly used to treat hypertension and heart failure by inhibiting the angiotensin-converting enzyme. ACE inhibitors do not belong to the categories mentioned in the other choices. Choice A (H) is vague and does not provide any relevant information. Choice C (Antifungal) is incorrect as drugs ending in (-pril) are not typically used to treat fungal infections. Choice D (Beta agonist) is also incorrect as drugs ending in (-pril) do not belong to the class of beta agonists, which are used to treat conditions like asthma and COPD.

Correct Answer: D

Rationale: The correct answer is D: Penicillamine. Penicillamine is a chelating agent that binds to copper and forms a complex that can be excreted from the body, making it an effective antidote for copper toxicity. Glucagon (A) is used for treating hypoglycemia, aminocaproic acid (B) is used to treat excessive bleeding, and atropine (C) is used to treat bradycardia and organophosphate poisoning, none of which are related to copper toxicity.

Correct Answer: B

Rationale: The correct answer is B: Liver. Warfarin is primarily metabolized in the liver by the cytochrome P450 enzyme system. The liver is responsible for breaking down and activating many drugs, including Warfarin. It is where the drug's metabolism and effects are most significant. The other choices are incorrect because Warfarin's main site of activity is in the liver, not the kidney, blood, or heart. The kidney mainly excretes the drug, while the blood carries it throughout the body, and the heart is not directly involved in Warfarin's metabolism.

Correct Answer: D

Rationale: The correct answer is D: Hyperactivity. Clozapine is an antipsychotic drug used for schizophrenia treatment. Agranulocytosis is a known severe side effect of Clozapine. Hyperactivity is not a known effect of Clozapine, as it actually has a sedative effect due to its mechanism of action in the brain. Therefore, option D is the correct answer. Options A, B, and C are incorrect as agranulocytosis is a known side effect, Clozapine is an antipsychotic drug, and it is commonly used for schizophrenia treatment.

Correct Answer: B

Rationale: The correct answer is B: Tachycardia. Atenolol is a beta-blocker that works by slowing down the heart rate, so tachycardia is not related to its toxicity. A: CHF can be exacerbated by Atenolol due to its negative inotropic effects. C: AV block can occur as Atenolol can further slow down the heart's conduction system. D: Sedative appearance can be a side effect of Atenolol due to its action on the central nervous system. In summary, tachycardia is not related to Atenolol toxicity because it decreases heart rate.

Correct Answer: A

Rationale: The correct answer is A: COPD. Ephedrine is a sympathomimetic drug that acts on alpha and beta adrenergic receptors, leading to vasoconstriction and increased heart rate. It is used to treat hypotension and congestion by increasing blood pressure and dilating airways, respectively. Incontinence is not typically treated with Ephedrine. However, COPD involves bronchoconstriction, which can worsen with Ephedrine due to its vasoconstrictive effects. Therefore, Ephedrine is not used to treat COPD.

Correct Answer: A

Rationale: Protamine is the antidote for Heparin toxicity because it binds to Heparin and forms a stable complex, neutralizing its anticoagulant effects. Protamine sulfate is positively charged, while Heparin is negatively charged, allowing them to bind effectively. Methylene blue is used to treat methemoglobinemia, not Heparin toxicity. N-acetylcysteine is used for acetaminophen overdose, and Glucagon is used for beta-blocker overdose.

Correct Answer: C

Rationale: Correct Answer: C (Isoniazid) Rationale: 1. Isoniazid is known to cause drug-induced hepatitis due to its hepatotoxic effects. 2. It can lead to liver inflammation, causing hepatitis as a reaction. 3. Regular monitoring of liver function tests is essential when using isoniazid. Summary of other choices: A. Valproic acid: Can cause hepatotoxicity but not specifically linked to hepatitis. B. Quinidine: Mainly known for cardiac side effects, not commonly associated with hepatitis. D. Ethosuximide: Primarily used for treating absence seizures, not typically associated with hepatitis.