All of the following statements about oral contraceptives are true EXCEPT:

Correct Answer: D

Rationale: The correct answer is D because the statement is false. The triphasic pill does not contain luteinizing hormone (LH). The triphasic pill contains varying levels of estrogen and progestin throughout the cycle to mimic the natural hormonal fluctuations in a woman's menstrual cycle. A: The combination pill does contain both estrogen and progestin, making statement A true. B: Ethinyl estradiol and mestranol are indeed commonly used in oral contraceptives, making statement B true. C: The minipill contains progestin alone, making statement C true. In summary, the incorrect statement is D because the triphasic pill does not contain luteinizing hormone. Statements A, B, and C are all true regarding oral contraceptives.

Correct Answer: A

Rationale: The correct answer is A because antienzymes are agents that inhibit or destroy enzymic activity. They can be inhibitory enzymes or antibodies that target specific enzymes. This definition aligns with the concept of antienzymes acting to retard or inhibit enzymatic activity. Choice B is incorrect because substances that prevent vitamins from exerting their effects are not related to antienzymes. Choice C describes enzymes, not antienzymes, which are the opposite in function. Choice D refers to coenzymes, which are required for enzyme activity, not antienzymes that inhibit or destroy enzymic activity.

Correct Answer: D

Rationale: Step-by-step rationale for the correct answer (D): 1. Aminoglutethimide is an aromatase inhibitor used in cancer therapy. 2. Aromatase inhibitors block the enzyme aromatase, which converts androgens to estrogens. 3. By inhibiting aromatase, aminoglutethimide reduces estrogen production, beneficial in hormone-sensitive cancers. 4. Physostigmine (A) is a cholinesterase inhibitor, Allopurinol (B) is a xanthine oxidase inhibitor, and Aminocaproic acid (C) is an antifibrinolytic agent, not aromatase inhibitors.

Correct Answer: D

Rationale: The correct answer is D: Probucol (Lorelco). Probucol blocks the oxidation of low-density lipoproteins (LDL) by inhibiting the formation of lipid peroxides. This is important in preventing the development of atherosclerosis. Lovastatin (A) works by inhibiting cholesterol synthesis, Nicotinic acid (B) lowers LDL and triglycerides but does not specifically block oxidation, and Gemfibrozil (C) decreases triglyceride levels but does not directly block LDL oxidation.

Correct Answer: C

Rationale: The correct answer is C: Oral. Alendronate is typically administered orally as it is a bisphosphonate used in the treatment of osteoporosis. The oral route ensures optimal absorption in the gastrointestinal tract. Intravenous and subcutaneous routes are not commonly used for alendronate due to potential adverse effects and practicality issues. Intranasal route is not a common administration method for alendronate. In summary, the oral route is preferred for alendronate administration due to its efficacy, safety, and convenience compared to other routes.