A drug ending in the suffix (tidine) is considered a ______.

Correct Answer: D

Rationale: The correct answer is D: H antagonist. Drugs ending in the suffix (tidine) typically belong to the class of histamine H2-receptor antagonists. These drugs work by blocking the action of histamine on H2 receptors in the stomach, reducing the production of stomach acid. This is commonly used to treat conditions such as peptic ulcers and gastroesophageal reflux disease. Explanation of other choices: A: Antidepressant - Drugs ending in (pramine) or (ine) are more commonly associated with antidepressants. B: Protease inhibitor - Drugs ending in (navir) are typically protease inhibitors used in antiviral therapy. C: Beta antagonist - Drugs ending in (olol) are beta-blockers, which are used to treat conditions such as hypertension and heart disease, not related to (tidine) suffix.

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: B

Rationale: The correct answer is B: Hypotension. Prednisone toxicity typically causes hypertension, not hypotension. Prednisone can lead to increased blood pressure due to its sodium-retaining effects. Cataracts (A), Psychosis (C), and Acne (D) are all known side effects of Prednisone toxicity. Cataracts can form due to long-term steroid use, psychosis can occur especially at higher doses, and acne is a common skin side effect. Therefore, hypotension is the odd one out among the choices given.

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: 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.