This drug is used intravenously to terminate supraventricular tachycardias:

Correct Answer: B

Rationale: The correct answer is B: Verapamil. Verapamil is a calcium channel blocker that slows conduction through the AV node, making it effective in terminating supraventricular tachycardias. Nifedipine, choice A, is also a calcium channel blocker but is not typically used intravenously for this purpose. Choice C is incorrect because only Verapamil is specifically indicated for terminating supraventricular tachycardias. Choice D is incorrect as Verapamil is the correct drug for this scenario.

Correct Answer: D

Rationale: The correct answer is D, the mammary gland. Prolactin is a hormone primarily responsible for mammary gland development and milk production in females. It stimulates the mammary alveolar cells to produce milk. The other choices, A: Liver, B: Adrenal cortex, and C: Thyroid, are not directly targeted by prolactin and do not have a primary role in milk production. Therefore, the correct answer is D as it directly correlates with the function of prolactin in the body.

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.