A 70-year-old female with osteoarthritis is prescribed celecoxib. Celecoxib works by:

Correct Answer: B

Rationale: The correct answer is B: Inhibiting COX-2 enzymes selectively. Celecoxib is a selective COX-2 inhibitor, meaning it specifically targets and inhibits the cyclooxygenase-2 enzyme, which is responsible for producing prostaglandins involved in inflammation and pain. By selectively inhibiting COX-2, celecoxib reduces inflammation and pain without affecting COX-1, which helps maintain the stomach lining and platelet function. Choice A (Inhibiting COX-1 and COX-2 enzymes) is incorrect because celecoxib primarily targets COX-2, not COX-1. Choice C (Binding to opioid receptors in the brain) is incorrect as celecoxib does not bind to opioid receptors but works through a different mechanism. Choice D (Inhibiting the synthesis of leukotrienes) is incorrect as celecoxib does not directly inhibit leukotriene synthesis; it primarily inhibits COX-2 enzymes

Correct Answer: B

Rationale: The correct answer is B: Binding to opioid receptors in the central nervous system. Oxycodone is an opioid analgesic that exerts its effects by binding to opioid receptors in the brain and spinal cord, which modulates pain perception. This mechanism of action is how oxycodone provides pain relief. A: Blocking sodium channels in peripheral nerves is incorrect because this mechanism is associated with local anesthetics, not opioids like oxycodone. C: Increasing the release of serotonin is incorrect as oxycodone does not directly affect serotonin levels. D: Inhibiting the reuptake of norepinephrine is incorrect as this is a mechanism seen in certain antidepressants, not opioids like oxycodone.

Correct Answer: B

Rationale: Sumatriptan is the correct answer because it is a specific medication called a triptan that is commonly prescribed to treat acute migraine attacks by targeting serotonin receptors to reduce inflammation and constrict blood vessels in the brain. Ibuprofen and aspirin are general pain relievers that may help with mild migraines but are not as effective for acute attacks. Lorazepam is a benzodiazepine used for anxiety and seizures, not for migraine treatment.

Correct Answer: C

Rationale: The correct answer is C: Inhibiting potassium channels in the heart. Amiodarone works by prolonging the action potential duration and refractory period by inhibiting potassium channels. This helps to stabilize the heart's rhythm in atrial fibrillation. Choices A, B, and D are incorrect because amiodarone does not directly affect sodium channels, beta-adrenergic receptors, or calcium influx into the myocardium. Sodium channel blockers are class I antiarrhythmics, beta-blockers target beta-adrenergic receptors, and drugs that increase calcium influx are typically used for other indications like heart failure.

Correct Answer: B

Rationale: The correct answer is B: Phenytoin. Phenytoin is an antiepileptic drug commonly used to manage seizures in patients with epilepsy. It works by stabilizing the neuronal membranes and inhibiting the spread of seizure activity. Aspirin (A) is a pain reliever and anti-inflammatory drug, not used for seizures. Metformin (C) is used for diabetes, not seizures. Furosemide (D) is a diuretic used for treating fluid retention, not seizures. Therefore, Phenytoin is the correct choice for managing seizures in patients with epilepsy.