An adult patient has been taking a drug (Drug A) that is highly metabolized by the cytochrome p-450 system. He has been on this medication for 6 months. At this time, he is started on a second medication (Drug B) that is an inducer of the cytochrome p-450 system. You should monitor this patient for:

Correct Answer: C

Rationale: Drug B, as an inducer of the cytochrome p-450 system, increases the metabolism of Drug A, leading to lower plasma concentrations and reduced therapeutic effects of Drug A. This interaction is a common concern in polypharmacy, where one drug affects the metabolism of another. Monitoring for decreased efficacy of Drug A is essential to ensure the patient receives adequate treatment. Increased adverse effects of Drug B or decreased effects of Drug B are less likely in this scenario.

Correct Answer: D

Rationale: Weight loss, tachycardia, and goitre suggest hyperthyroidism (e.g., Graves'). Verapamil controls rate but not thyroid function. Radioactive iodine (131I) treats long-term, not immediately. Carbamazepine is for seizures, L-thyroxine worsens hyperthyroidism. Atenolol, a beta-blocker, immediately reduces tachycardia and symptoms by blocking adrenergic effects, suitable for acute management while awaiting antithyroid drugs (e.g., propylthiouracil). Its symptomatic relief is critical in hyperthyroid crises.

Correct Answer: C

Rationale: Higher potency (lower dose for effect) can coexist with lower efficacy (max effect), true, as potency reflects affinity, not ceiling effect. Higher receptor affinity increases potency, true, per receptor theory. Lower potency doesn't mandate lower efficacy; a less potent drug can achieve the same max effect with more dose, making this false. Higher potency with equal efficacy is true (e.g., partial agonists). This pharmacodynamic distinction is vital for drug selection, where efficacy often trumps potency.

Correct Answer: C

Rationale: Anatomy, physiology, and microbiology underpin pharmacology, enabling nurses to grasp drug actions and patient responses, enhancing care through informed medication use. As an outgrowth oversimplifies their integration. Curriculum mandates explain requirements, not value. Understanding is key, but applying it to care-like knowing antibiotic targets or drug effects on organs-grounds pharmacology in practice, making it the best rationale.

Correct Answer: D

Rationale: Doubling a therapeutic dose exceeds the plateau-efficacy maxes out, but side effects (e.g., sedation) rise with excess, especially in the elderly with slower clearance. Tolerance needs chronic use, not one event. More relief assumes linear gain, not true. Tolerance requiring more is future, not immediate. Side effects reflect pharmacodynamics, a key risk.