Which of the following medications is most commonly used for the treatment of opioid addiction?

Correct Answer: A

Rationale: The correct answer is A: Methadone. Methadone is a long-acting opioid agonist that helps reduce withdrawal symptoms and cravings in individuals with opioid addiction. It has been widely used for decades in medication-assisted treatment programs. Naltrexone (B) is an opioid antagonist that is used for relapse prevention, not as a first-line treatment. Naloxone (C) is an opioid antagonist used for emergency overdose reversal. Suboxone (D) is a combination of buprenorphine (a partial opioid agonist) and naloxone, commonly used for opioid addiction treatment, but methadone is more commonly used.

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: Inhibiting the action of HMG-CoA reductase in the liver. Pravastatin is a statin medication that works by inhibiting the enzyme HMG-CoA reductase, which plays a key role in the liver's production of cholesterol. By blocking this enzyme, pravastatin reduces the liver's ability to produce cholesterol, leading to lower levels of LDL cholesterol in the bloodstream. This mechanism helps to lower the risk of cardiovascular events in patients with hyperlipidemia. Choice A is incorrect because pravastatin does not inhibit the absorption of cholesterol in the intestines; it primarily acts in the liver. Choice C is incorrect because pravastatin primarily lowers LDL cholesterol levels rather than increasing HDL cholesterol levels. Choice D is incorrect because blocking bile acid reabsorption is not the primary mechanism of action of pravastatin in managing hyperlipidemia.

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.