This is a drug of choice for acute treatment of ventricular tachycardias:

Correct Answer: C

Rationale: Rationale: Lidocaine is the drug of choice for acute treatment of ventricular tachycardias due to its fast onset of action and minimal negative inotropic effects. It works by stabilizing cell membranes and reducing automaticity in the ventricular tissue. Flecainide (A) and Sotalol (B) are contraindicated in ventricular tachycardias due to their potential to worsen arrhythmias. Verapamil (D) is a calcium channel blocker and is not effective for treating ventricular tachycardias.

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.

Correct Answer: C

Rationale: The correct answer is C: Inhibits calcineurin. Cyclosporine A works by inhibiting calcineurin, a protein phosphatase that is crucial for the activation of T cells. By blocking calcineurin, cyclosporine A prevents the production of interleukin-2, a key cytokine involved in T cell activation and proliferation. This ultimately leads to suppression of the immune response. Choices A, B, and D are incorrect: A: Complement-mediated cytolysis of T lymphocytes is not the mechanism of action of cyclosporine A. B: ADCC towards T lymphocytes does not describe how cyclosporine A works. D: Competing for Fc receptors with autoantibodies is not related to the mechanism of action of cyclosporine A.