What does the term “potentiation” mean?

Correct Answer: D

Rationale: The term "potentiation" refers to the intensive increase of drug effects due to their combination. This is the correct answer because potentiation occurs when one drug enhances the effects of another drug when taken together. It's important to note that potentiation is different from cumulative ability (A), which refers to the build-up of a drug's effects over time. It is also distinct from hypersensitivity (B), which is an exaggerated response to a drug due to individual factors. Additionally, potentiation is not the same as fast tolerance developing (C), which is when the body becomes less responsive to a drug with repeated use. In summary, the correct answer, option D, best describes the concept of potentiation in pharmacology.

Correct Answer: A

Rationale: The correct answer is A: Atropine. Atropine is an anticholinergic medication that blocks the action of acetylcholine, leading to decreased tear production and dry eyes. This is why patients complain of dry or "sandy" eyes when receiving large doses of Atropine. Summary of other choices: B: Hexamethonium - This is a ganglionic blocking agent used in hypertension, not associated with dry eyes. C: Pilocarpine - This is a cholinergic agonist used to treat glaucoma by increasing tear production, opposite effect of dry eyes. D: Carbachol - This is a cholinergic agonist used in glaucoma, not associated with dry eyes.

Correct Answer: C

Rationale: Rationale: 1. Ephedrine acts indirectly by stimulating release of norepinephrine from nerve terminals. 2. Epinephrine (A) and norepinephrine (B) act directly on adrenergic receptors. 3. Methoxamine (D) is a direct acting alpha-1 agonist. Summary: A, B, and D directly stimulate adrejsonceptors, while only C acts indirectly by promoting norepinephrine release.

Correct Answer: C

Rationale: The correct answer is C: Epinephrine. Epinephrine is a sympathomimetic agent that acts on both alpha and beta adrenergic receptors, increasing heart rate, contractility, and vasoconstriction. In cardiac arrest, epinephrine is crucial for improving coronary and cerebral perfusion, leading to increased chances of successful resuscitation. Methoxamine (A) and Phenylephrine (B) are pure alpha-adrenergic agonists with minimal cardiac effects, not ideal for cardiac arrest. Xylometazoline (D) is a nasal decongestant and has no role in cardiac arrest management.

Correct Answer: D

Rationale: The correct answer is D: Propranolol. Propranolol is the preferred beta-blocker for thyroid storm due to its non-selective beta-adrenergic blockade, which helps control symptoms such as tachycardia and hypertension. It also inhibits the peripheral conversion of T4 to T3. Pindolol (A) is a partial beta-blocker with intrinsic sympathomimetic activity, not ideal for thyroid storm. Sotalol (B) is a non-selective beta-blocker with class III antiarrhythmic properties, not typically used in thyroid storm. Phentolamine (C) is an alpha-blocker, not a beta-blocker, and not indicated for thyroid storm.