Which of the following drugs is an antiprogestin:

Correct Answer: C

Rationale: Step-by-step rationale: 1. Mifepristone is an antiprogestin as it competitively inhibits progesterone receptors. 2. Gemeprost is a prostaglandin analog, not an antiprogestin. 3. Megestrol is a progestin, promoting progesterone-like effects. 4. Tamoxifen is a selective estrogen receptor modulator, not an antiprogestin. Summary: A, B, and D are incorrect as they do not possess antiprogestin properties. Mifepristone is the correct choice due to its specific mechanism of action as an antiprogestin.

Correct Answer: D

Rationale: The correct answer is D: Improved lipid profile. Tamoxifen citrate therapy does not have a direct effect on improving lipid profile. A: Reduction in recurrence rate of breast cancer - Tamoxifen is used to reduce the risk of breast cancer recurrence. B: Improved bone mass - Tamoxifen can help maintain or improve bone density. C: Suppression of menopausal hot flushes - Tamoxifen can help reduce menopausal symptoms like hot flushes. In summary, choices A, B, and C are benefits of tamoxifen therapy, while choice D is not supported by evidence.

Correct Answer: D

Rationale: The correct answer is D (2-4 weeks) because rotating injection sites every 2-4 weeks helps prevent lipodystrophy and tissue damage. Insulin absorption may vary with frequent rotation, affecting glucose control. Choice A is too frequent and may lead to overuse of specific sites, increasing the risk of complications. Choice B is also too frequent and doesn't allow enough time for the tissue to recover. Choice C is too long, increasing the likelihood of uneven insulin absorption and potential complications. Rotation every 2-4 weeks strikes a balance between preventing damage and ensuring consistent insulin absorption.

Correct Answer: B

Rationale: The correct answer is B: Norepinephrine. The sympathetic postganglionic neurons release norepinephrine as the main neurotransmitter, which acts on target organs to elicit the fight-or-flight response. Norepinephrine is responsible for increasing heart rate, blood pressure, and dilating airways. Acetylcholine is released by preganglionic neurons in both sympathetic and parasympathetic systems, not postganglionic neurons in the sympathetic system. Option C is incorrect as acetylcholine is not typically released by postganglionic sympathetic neurons. Option D, arginine, is not a neurotransmitter commonly associated with the sympathetic nervous system.

Correct Answer: A

Rationale: Norepinephrine is a vasoconstrictor that increases blood pressure. In hypovolemic shock, there is insufficient blood volume, so vasoconstriction can worsen tissue perfusion. Neurogenic shock is characterized by vasodilation, so norepinephrine can help increase blood pressure. Choice C is incomplete and irrelevant. Norepinephrine is not used to treat diabetes.