Immediate allergy reaction (type I allergic reaction) is:

Correct Answer: A

Rationale: The correct answer is A because an immediate allergy reaction, also known as a type I allergic reaction, typically occurs within minutes to about an hour after exposure to an antigen. This rapid onset is characteristic of type I hypersensitivity reactions mediated by IgE antibodies. It involves the release of histamine and other inflammatory mediators from mast cells and basophils, leading to symptoms such as hives, itching, swelling, and in severe cases, anaphylaxis. Choice B is incorrect because it describes a delayed allergic reaction, which usually takes hours to days to develop. Choice C is incorrect as it describes type II hypersensitivity reactions involving IgM or IgG antibodies, not type I reactions. Choice D is incorrect as it describes type III hypersensitivity reactions involving antigen-antibody complexes, not type I reactions.

Correct Answer: D

Rationale: Acetazolamide is a carbonic anhydrase inhibitor. It works by blocking carbonic anhydrase enzyme, reducing the production of bicarbonate ions and consequently decreasing fluid production in the eye, reducing intraocular pressure. Physostigmine is an acetylcholinesterase inhibitor used in glaucoma. Selegiline is a monoamine oxidase inhibitor used in Parkinson's disease. Aminocaproic acid is an antifibrinolytic used to treat excessive bleeding. Therefore, the correct answer is D as it directly inhibits the carbonic anhydrase enzyme.

Correct Answer: B

Rationale: Step 1: Lovastatin inhibits HMG-CoA reductase, an enzyme involved in cholesterol synthesis. Step 2: Inhibiting HMG-CoA reductase leads to upregulation of LDL receptors, enhancing LDL clearance. Step 3: Therefore, Lovastatin both inhibits an enzyme and indirectly enhances LDL clearance. Summary: A: Cholestyramine binds bile acids, not related to LDL clearance. C: Nicotinic acid primarily affects HDL levels, not directly related to LDL clearance. D: Probucol mainly acts by increasing HDL levels, not directly related to LDL clearance.

Correct Answer: D

Rationale: The correct answer is D: Intravenous. Pamidronate is a bisphosphonate used to treat bone diseases like osteoporosis. Intravenous route ensures rapid and complete absorption, leading to optimal therapeutic effects. Oral administration (A) would result in poor bioavailability. Subcutaneous (B) and intranasal (C) routes are not commonly used for pamidronate due to inconsistent absorption and inadequate therapeutic levels. Therefore, intravenous administration is the preferred route for pamidronate to achieve the desired clinical outcomes.

Correct Answer: B

Rationale: The correct answer is B: Thiazide diuretics. Thiazide diuretics act in the distal convoluted tubule by inhibiting the sodium-chloride symporter, leading to increased sodium and water excretion. This results in decreased blood volume and reduced blood pressure. Loop diuretics (A) act in the loop of Henle, potassium-sparing diuretics (C) act in the collecting duct, and carbonic anhydrase inhibitors (D) act in the proximal convoluted tubule. Thiazide diuretics are preferred for conditions like hypertension and edema due to their efficacy and site of action in the distal convoluted tubule.