Upon preparing to administer activated charcoal by mouth to treat a patient who took an overdose of aspirin and several unknown drugs, the nurse notes that the patient has become very somnolent and eyes open only to a noxious stimulus. Which action by the nurse is most appropriate at this point?

Correct Answer: A

Rationale: The patient's decreased level of consciousness (somnolence and only responding to noxious stimuli) indicates a potential deterioration in their condition, possibly due to the overdose. Activated charcoal is contraindicated in patients with an altered mental status due to the risk of aspiration. The nurse should immediately consult the nurse practitioner to reassess the patient's condition and determine the appropriate intervention, such as securing the airway or considering alternative treatments.

Correct Answer: B

Rationale: Apnea is the most serious adverse effect of alprostadil in neonates, requiring close monitoring and respiratory support. Alprostadil is used to maintain ductus arteriosus patency in congenital heart defects, but its use carries significant risks. Bleeding, hypotension, and fever are also possible but are less critical than apnea.

Correct Answer: D

Rationale: Plasma concentration monitoring optimizes drugs with narrow therapeutic indices or variable pharmacokinetics. Warfarin uses INR, not plasma levels, for anticoagulation control. Omeprazole, a proton pump inhibitor, relies on symptom relief, not levels. Salbutamol, a bronchodilator, is titrated by response, not plasma monitoring. Olanzapine's dosing is guided by efficacy and side effects, not routine levels. Ciclosporin, an immunosuppressant, requires plasma monitoring (e.g., 100-400 ng/mL) due to its narrow therapeutic range, interindividual variability, and risk of toxicity or rejection in transplant patients. This ensures efficacy while minimizing nephrotoxicity, a cornerstone of therapeutic drug monitoring.

Correct Answer: D

Rationale: Heparin is an anticoagulant that enhances the activity of antithrombin III, a natural inhibitor of thrombin and factor Xa, to prevent clotting. The statement that it inhibits clotting by decreasing antithrombin III effects is false, as heparin actually potentiates antithrombin III, making this the incorrect option. Its oral bioavailability is negligible (not 20-30%), as it's a large polysaccharide requiring parenteral administration (e.g., IV or subcutaneous), so this is false. Heparin is highly plasma protein-bound, not low, contradicting that option. The correct statement, replaced in the fourth slot, is that heparin binds to antithrombin III, causing a conformational change that accelerates its anticoagulant effect. This mechanism is fundamental to its clinical use in thrombosis prevention, distinguishing it from oral anticoagulants like warfarin.

Correct Answer: C

Rationale: Sildenafil (Viagra), a phosphodiesterase-5 inhibitor for erectile dysfunction, has a recommended dosing limit of one pill per 24 hours to prevent overdose risks like prolonged erections or cardiovascular strain, making this a critical safety instruction. Grapefruit juice actually increases sildenafil levels by inhibiting metabolism, not decreasing effects, which could heighten side effects. Timing is optimal at 1 hour before sex, with effectiveness possible up to 4 hours, not 6, ensuring accurate expectations. Taking it on an empty stomach enhances absorption, as food-especially high-fat meals-delays onset, contrary to the food suggestion. The 24-hour limit is foundational for safe use, balancing efficacy with minimizing adverse effects like headache or hypotension, and aligns with standard prescribing guidelines, making it the priority in client education.