A 39-year-old man with chronic allergic rhinitis and nasal congestion takes an over-the-counter nasal spray containing oxymetazoline. Over the next few days, he has significant improvement in his symptoms. Which of the following is the most likely mechanism of action of this agent?

Correct Answer: C

Rationale: Oxymetazoline treats nasal congestion in allergic rhinitis by acting as an α-adrenergic agonist. Option , increased nasal blood flow, is incorrect-vasoconstriction reduces flow. Option , increased arterial pressure, doesn't directly relieve congestion. Option , receptor stimulation on nasal vasculature, is correct-oxymetazoline stimulates α-receptors, causing vasoconstriction, shrinking swollen mucosa, and improving airflow. Option , transmembrane conductance change, is unrelated to its action. Option (E), understimulation, contradicts its agonist role. This vasoconstrictive effect rapidly alleviates congestion, explaining the symptom improvement. Unlike antihistamines or steroids, oxymetazoline targets vascular tone, not inflammation or histamine, making it ideal for quick relief in rhinitis. Prolonged use risks rebound congestion, but the question focuses on initial efficacy, where receptor-mediated vasoconstriction is key.

Correct Answer: C

Rationale: Paroxetine, an SSRI, treats depression by inhibiting serotonin reuptake, often improving mood. Its side effects include agitation and insomnia (especially if taken late), due to serotonin's stimulating effects, and weight loss can occur initially, unlike TCAs which cause gain. A critical clue is the warning against opioids like meperidine: SSRIs can cause serotonin syndrome when combined with MAOIs or other serotonergic drugs, though meperidine's risk is notable in polypharmacy. Alprazolam, a benzodiazepine, sedates rather than agitates. Chlorpromazine, an antipsychotic, causes sedation and weight gain. Amitriptyline, a TCA, is sedating and linked to weight gain, not loss. Trazodone promotes sleep. Paroxetine's profile—activation, insomnia, weight loss, and drug interaction risks—matches the patient's experience.

Correct Answer: A

Rationale: Superinfections are secondary infections that occur as a result of disrupting the normal balance of microorganisms in the body, often due to prolonged or broad-spectrum antibiotic use. They can involve the emergence of resistant strains or the overgrowth of opportunistic pathogens. Therefore, superinfections are more likely to occur with prolonged antibiotic use or broad-spectrum antibiotics that disrupt the normal flora of the body. It is less common for superinfections to occur with narrow spectrum antibiotics, as they target a more limited range of bacteria and are less likely to disrupt the overall microbial balance in the body.

Correct Answer: B

Rationale: Sodium bisulfite is commonly added to local anesthetic solutions as a vasoconstrictor. Vasoconstrictors work by constricting blood vessels at the site of injection. This helps to reduce blood flow to the area, which in turn decreases bleeding, prolongs the anesthetic effect, and reduces the risk of systemic toxicity by slowing the absorption of the anesthetic into the bloodstream. Sodium bisulfite specifically acts as a vasoconstrictor in local anesthetics to enhance the overall effectiveness of the numbing agent.

Correct Answer: C

Rationale: Physostigmine, a cholinesterase inhibitor, lowers IOP in glaucoma by increasing aqueous outflow . It contracts the ciliary muscle, opening the trabecular meshwork. Secretion or synthesis reduction isn't its mechanism. Raising pressure (D, E) contradicts its use. This aids drainage in open-angle glaucoma.

Correct Answer: A

Rationale: Interferon Alfa-2b, used for hepatitis or cancer, commonly causes flu-like symptoms—dizziness , fatigue , and anorexia —due to its immune-modulating effects. Dizziness reflects CNS impact, often early in therapy, while fatigue and appetite loss stem from systemic inflammation. An itchy rash might suggest hypersensitivity but is less frequent than these systemic effects. The nurse identifies dizziness as a common adverse effect (correct answers: 1, 3, 4), distinguishing it from severe reactions requiring intervention. This aligns with interferon's side effect profile, where patients often report such symptoms within days of starting, necessitating education on management (e.g., rest, hydration). Choice A is a key identifier among expected effects, ensuring appropriate monitoring.

Correct Answer: B

Rationale: OTC medications can interact to increase or decrease the effects of antiadrenergic drugs. Antacids decrease the effects of beta-adrenergic blocking drugs. Decreased antihypertensive effects result when taken with ibuprofen. Other options reflect correct statements and would not indicate that the patient would need further instruction. The nurse should educate the patient about potential drug interactions and the importance of consulting their healthcare provider before taking OTC medications.

Correct Answer: B

Rationale: Enteral formulas are categorized as elemental/semi-elemental (B), disease-specific (C), polymeric formula (D), and modular formula (E). Enteral macronutrient (A) is not a recognized category. These formulas are tailored to meet specific nutritional needs based on the patient's condition.

Correct Answer: A

Rationale: A. You need to have your blood pressure checked once a week and keep track of the readings. - This statement is correct because monitoring blood pressure regularly is essential when taking antihypertensive medications to ensure they are effectively controlling hypertension.