Tick the drug type for which microsomal oxidation is the most prominent:

Correct Answer: A

Rationale: Microsomal oxidation is primarily mediated by cytochrome P450 enzymes located in the endoplasmic reticulum of hepatocytes. Lipid-soluble drugs can easily penetrate cell membranes to reach the microsomes where cytochrome P450 enzymes are located, making microsomal oxidation most prominent for lipid-soluble drugs. Water-soluble drugs have limited access to microsomes, reducing the likelihood of undergoing significant microsomal oxidation. Low molecular weight drugs are generally more likely to be lipid-soluble and undergo microsomal oxidation, while high molecular weight drugs may be too large to efficiently access microsomes for this metabolic pathway. Therefore, the correct choice is A: Lipid soluble.

Correct Answer: B

Rationale: The correct answer is B: Low potency. Tetracaine is a potent local anesthetic with high potency. It has a slow onset, long duration, and high toxicity. Low potency would imply weaker anesthetic effects, which is not true for tetracaine. Other choices are incorrect as tetracaine is known for its strong anesthetic properties.

Correct Answer: B

Rationale: The correct answer is B: Secretions. Atropine is used to reduce respiratory secretions before inhaling anesthetics as it helps prevent airway obstruction and aspiration. It does not affect muscle tone or nausea/vomiting. Choice A is incorrect because atropine can actually increase muscle tone. Choice C is incorrect because atropine does not directly address nausea and vomiting. Overall, the main purpose of using atropine in this context is to decrease secretions, making option B the correct answer.

Correct Answer: A

Rationale: The correct answer is A: Ephedrine. Catecholamines are a class of neurotransmitters that include epinephrine, norepinephrine, and isoprenaline. Ephedrine is a sympathomimetic amine, not a catecholamine. Ephedrine acts by stimulating both alpha and beta-adrenergic receptors, while catecholamines specifically act on adrenergic receptors. Therefore, ephedrine does not fit the definition of a catecholamine, making it the correct answer. Epinephrine, norepinephrine, and isoprenaline are all true catecholamines.

Correct Answer: D

Rationale: The correct answer is D: Epinephrine. 1. Epinephrine is the drug of choice in anaphylactic shock due to its alpha and beta-adrenergic effects, which help reverse vasodilation, bronchoconstriction, and increased vascular permeability. 2. Methoxamine (A) acts as a selective alpha-1 adrenergic agonist and may worsen the vasodilation in anaphylactic shock. 3. Terbutaline (B) is a beta-2 adrenergic agonist used in asthma but may not be as effective in reversing the systemic effects of anaphylactic shock. 4. Norepinephrine (C) is a potent vasoconstrictor but lacks the beta-adrenergic effects needed to reverse bronchoconstriction and vascular permeability in anaphylactic shock.