The nurse is monitoring drug levels for a patient who is receiving theophylline. The most recent theophylline level was 13 mcg/mL, and the nurse evaluates this level to be

Correct Answer: B

Rationale: The correct answer is B: at a therapeutic level. The therapeutic range for theophylline is typically 10-20 mcg/mL. A level of 13 mcg/mL falls within this range, indicating the drug is at an appropriate concentration to provide therapeutic effects without causing toxicity. Choices A, C, and D are incorrect because they do not align with the established therapeutic range for theophylline. A level below the therapeutic range (Choice A) would indicate subtherapeutic effects, whereas a level above the therapeutic range (Choice C) would suggest potential for toxicity. A level at a toxic level (Choice D) would indicate a concentration that is harmful to the patient.

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: B

Rationale: The correct answer is B: It has esteratic linkage. Lidocaine is an amide-type local anesthetic, not an ester. It is not a universal anesthetic (A), as it is mainly used for local anesthesia. It is widely used as an antiarrhythmic agent (C) due to its ability to stabilize cell membranes in the heart. Lidocaine is metabolized in the liver (D) by the cytochrome P450 enzyme system. Therefore, B is incorrect because lidocaine does not have an esteratic linkage.

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.