This drug routinely produces some tachycardia:

Correct Answer: D

Rationale: Step-by-step rationale: 1. Nifedipine is a calcium channel blocker that causes vasodilation. 2. Vasodilation leads to a decrease in blood pressure. 3. To compensate, the body may exhibit reflex tachycardia. 4. Therefore, nifedipine routinely produces tachycardia. Summary of incorrect choices: A. Propranolol is a beta-blocker that slows heart rate. B. Clonidine is a centrally-acting alpha-2 agonist that decreases sympathetic outflow, leading to bradycardia. C. Enalapril is an ACE inhibitor that does not directly affect heart rate.

Correct Answer: D

Rationale: The correct answer is D, All of the above. Glucagon, adrenal steroids, and adrenaline are important hormonal antagonists of insulin. Glucagon promotes glucose release from the liver, counteracting insulin's effects. Adrenal steroids and adrenaline increase blood sugar levels by promoting gluconeogenesis and glycogenolysis. Therefore, all these agents act against insulin to regulate blood glucose levels. Other choices are incorrect because each agent individually plays a role in antagonizing insulin's effects.

Correct Answer: C

Rationale: The correct answer is C: Meclofenamic acid. Fenamate derivatives are a specific class of NSAIDs that have a fenamic acid structure. Meclofenamic acid is a fenamate derivative as it contains the fenamic acid structure, making it the correct choice. A: Phenylbutazone is not a fenamate derivative, it belongs to the pyrazolidinedione class. B: Indomethacin is not a fenamate derivative, it belongs to the indoleacetic acid class. D: Diclofenac is not a fenamate derivative, it belongs to the acetic acid class.

Correct Answer: D

Rationale: The correct answer is D: 21 days. The half-life of I.V. IgG preparation is significantly longer compared to the other options. IgG has a long half-life of approximately 21 days due to its structural properties that allow it to circulate in the body for an extended period. This prolonged half-life is crucial for maintaining therapeutic levels of IgG in the body over an extended period. Options A, B, and C have much shorter half-lives compared to IgG, making them incorrect choices for this question.

Correct Answer: C

Rationale: The correct answer is C: Pyridoxine. Isoniazid used in tuberculosis treatment can lead to pyridoxine deficiency, causing peripheral neuropathy. Therefore, supplementing with pyridoxine is essential. Nicotinic acid (A) is not directly related to isoniazid therapy. Riboflavin (B) deficiency is not a common issue with isoniazid. Ascorbic acid (D) does not play a role in preventing isoniazid-induced neuropathy.