The drug used for controlling tetany is:

Correct Answer: C

Rationale: The correct answer is C: Intravenous calcium gluconate. Tetany is caused by low levels of calcium in the blood. Calcium gluconate is the appropriate treatment as it quickly and effectively raises blood calcium levels. Diazepam (A) is a muscle relaxant, vitamin D (B) is used for bone health, and calcitonin (D) is used to regulate calcium and phosphate levels in the body, but they are not the primary treatment for tetany.

Correct Answer: A

Rationale: The correct answer is A: Long acting progestin. Injectable hormonal contraceptives typically contain progestin alone, as it suppresses ovulation and thickens cervical mucus. Estrogen is not commonly used in injectable contraceptives due to its higher risk of side effects like blood clots. Chorionic gonadotropin is not a component of injectable contraceptives and is typically used in fertility treatments. Therefore, choice A is correct as it aligns with the mechanism of action and formulation of injectable hormonal contraceptives.

Correct Answer: C

Rationale: The correct answer is C because progestin and estrogen work together to suppress ovulation by inhibiting the release of gonadotropins. Progestin thickens cervical mucus, making it hostile to sperm, while estrogen stabilizes the endometrium. Choices A and B are incorrect because the hormones don't block each other's side effects. Choice D is incorrect because it oversimplifies the mechanism of action.

Correct Answer: D

Rationale: Step-by-step rationale for choice D being correct: 1. Oral mifepristone is a progesterone receptor antagonist, leading to detachment of the pregnancy. 2. Oral misoprostol, a prostaglandin, causes uterine contractions and expulsion of the products of conception. 3. This regimen is safe, effective, and widely used for early pregnancy termination. 4. Choice A, B, and C involve different medications and routes not typically used for nonsurgical termination of early pregnancy.

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.