Which of the following is considered a class IA Sodium Channel blocker?

Correct Answer: D

Rationale: The correct answer is D: Procainamide. Procainamide is a class IA antiarrhythmic drug that blocks sodium channels, prolonging the action potential duration. This helps to stabilize the heart's rhythm. Mexiletine (A) is a class IB antiarrhythmic drug that blocks sodium channels with fast recovery kinetics. Amiodarone (B) is a class III antiarrhythmic drug that prolongs repolarization by blocking potassium channels. Quinidine (C) is a class IA antiarrhythmic drug that also blocks sodium channels, but it is not a class IB sodium channel blocker like Procainamide.

Correct Answer: C

Rationale: The correct answer is C: Tetracycline. Tetracycline is associated with extreme photosensitivity due to its mechanism of action causing phototoxic reactions when exposed to sunlight. Digitalis (A) is a cardiac medication, niacin (B) is a B vitamin, and fluoroquinolones (D) are antibiotics, none of which are known to cause extreme photosensitivity reactions.

Correct Answer: D

Rationale: Step-by-step rationale: 1. Midazolam is a benzodiazepine commonly used as a sedative and anxiolytic. 2. Common effects of Midazolam include amnesia, decreased respiratory function, and anesthetic properties. 3. Dizziness is not a common effect of Midazolam but can be a side effect in some individuals. 4. Therefore, choice D (Dizziness) is not a common effect of Midazolam, making it the correct answer. Summary: - A: Amnesia - Common effect of Midazolam - B: Decreased respiratory function - Common effect of Midazolam - C: Anesthetic - Common effect of Midazolam - D: Dizziness - Not a common effect of Midazolam, making it the correct answer.

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.

Correct Answer: D

Rationale: The correct answer is D: Muscle wasting. Ibuprofen is primarily associated with gastrointestinal side effects like nausea, renal dysfunction, and anemia due to its effects on the stomach, kidneys, and blood. Muscle wasting is not a known direct effect of Ibuprofen toxicity. Ibuprofen is not typically linked to muscle-related issues, making choice D the correct answer.

Correct Answer: A

Rationale: The correct answer is A: Elevated lipid levels. Isoflurane does not cause elevated lipid levels. Isoflurane is a general anesthetic that primarily affects the central nervous system, leading to effects like decreased respiratory function and increased blood flow to the brain. Nausea can also be a side effect of isoflurane due to its impact on the gastrointestinal system. However, there is no direct link between isoflurane and elevated lipid levels. Thus, choice A is the correct answer.

Correct Answer: D

Rationale: The correct answer is D: Procainamide. Procainamide is a class IA antiarrhythmic drug that blocks sodium channels, prolonging the action potential duration. This helps to stabilize the heart's rhythm. Mexiletine (A) is a class IB antiarrhythmic drug that blocks sodium channels with fast recovery kinetics. Amiodarone (B) is a class III antiarrhythmic drug that prolongs repolarization by blocking potassium channels. Quinidine (C) is a class IA antiarrhythmic drug that also blocks sodium channels, but it is not a class IB sodium channel blocker like Procainamide.

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: Explanation: Dexamethasone is a corticosteroid used to treat inflammation and conditions like asthma and Addison's disease, which involve inflammation or immune responses. Wilson's disease is a genetic disorder related to copper metabolism, not treated with Dexamethasone. Dexamethasone could worsen Wilson's disease due to its potential impact on copper levels.