Heparin is effective when administred orally. This consideration is:

Correct Answer: B

Rationale: Step 1: Heparin is a medication with poor oral bioavailability, meaning it is not effectively absorbed when taken orally. Step 2: For heparin to be effective, it needs to be administered via injection or infusion to reach therapeutic levels. Step 3: Therefore, the statement that heparin is effective when administered orally is false. Summary: Choice B is correct because heparin's efficacy is not achieved through oral administration. Choices A, C, and D are incorrect because they do not acknowledge the pharmacokinetics of heparin.

Correct Answer: A

Rationale: The correct answer is A: Propranolol. Propranolol is a beta-blocker that inhibits renin synthesis by blocking beta-1 adrenergic receptors in the juxtaglomerular cells of the kidney. This leads to decreased renin release and ultimately reduces the production of angiotensin II. Enalapril (B) is an ACE inhibitor that acts downstream by inhibiting the conversion of angiotensin I to angiotensin II. Diazoxide (C) is a potassium channel activator and Losartan (D) is an angiotensin II receptor blocker, both of which do not directly inhibit renin synthesis.

Correct Answer: D

Rationale: The correct answer is D because hormone analogues are synthetic compounds that mimic the structure and function of naturally occurring hormones. This is important for therapeutic purposes as they can be used to replace or mimic the actions of hormones in the body. A is incorrect because hormone analogues are not naturally occurring substances but rather synthetic compounds. B is incorrect as hormone analogues can be equally or even more efficacious than naturally occurring hormones. C is incorrect because although hormone analogues may have similar structures to hormones, they do not necessarily have the same pharmacological properties.

Correct Answer: A

Rationale: Rationale: Glibenclamide is a sulfonylurea drug that acts by closing ATP-sensitive potassium channels in beta islet cells, leading to calcium influx and insulin release. It stimulates both insulin synthesis and release. Phenformin, Buformine, and Metformin do not directly stimulate insulin release, making them incorrect choices.

Correct Answer: A

Rationale: The correct answer is A: TRUE. Selective COX-2 inhibitors are safer than nonselective COX-1 inhibitors due to reduced risk of gastrointestinal side effects while maintaining efficacy. This is because COX-2 inhibitors target inflammation specifically, sparing COX-1 which is important for gastric mucosal protection. Nonselective COX-1 inhibitors can lead to gastric ulcers and bleeding. The other choices are incorrect: B: FALSE - selective COX-2 inhibitors are indeed safer than nonselective COX-1 inhibitors; C: None - this choice does not provide any information; D: All of the above - this choice is incorrect as only option A is true.