Which of the following drugs is used as an antidote for acetaminophen toxicity?

Correct Answer: B

Rationale: The correct answer is B: N-acetylcysteine. N-acetylcysteine is used as an antidote for acetaminophen toxicity by replenishing glutathione stores in the liver, which helps to prevent liver damage. Naloxone (A) is an opioid antagonist, used for opioid overdose. Flumazenil (C) is a benzodiazepine antagonist, used for benzodiazepine overdose. Activated charcoal (D) is used to absorb ingested toxins in the gastrointestinal tract but is not specific to acetaminophen toxicity.

Correct Answer: B

Rationale: The correct answer is B because ibuprofen inhibits the action of COX enzymes, specifically COX-1 and COX-2, which are responsible for the production of prostaglandins. Prostaglandins are lipid compounds that play a key role in inflammation and pain. By inhibiting COX enzymes, ibuprofen reduces the production of prostaglandins, thereby decreasing inflammation and pain. Choice A is incorrect because ibuprofen actually decreases the synthesis of prostaglandins by inhibiting COX enzymes instead of increasing their synthesis. Choice C is incorrect because ibuprofen does not bind to opioid receptors in the brain like opioid medications do. Choice D is incorrect because ibuprofen does not block the reuptake of serotonin, which is a mechanism of action seen in certain antidepressant medications, not NSAIDs like ibuprofen.

Correct Answer: C

Rationale: The correct answer is C: Blocking leukotriene receptors in the lungs. Montelukast is a leukotriene receptor antagonist, specifically targeting the cysteinyl leukotriene receptor, to reduce inflammation, bronchoconstriction, and mucus production in asthma. This mechanism helps in preventing asthma symptoms and attacks. Choice A is incorrect because blocking beta-2 adrenergic receptors would lead to bronchoconstriction and worsen asthma symptoms. Choice B is incorrect as histamine release is not the main target of montelukast. Choice D is also incorrect as stimulating acetylcholine release would not help in managing asthma and would likely exacerbate symptoms.

Correct Answer: B

Rationale: Certainly! The correct answer is B: Naloxone. Naloxone is an opioid receptor antagonist that rapidly reverses the effects of opioids, including respiratory depression, during an overdose. By competitively binding to opioid receptors, naloxone displaces the opioids and restores normal breathing. Flumazenil (A) is used to reverse the effects of benzodiazepines, not opioids. Atropine (C) is a medication used to treat certain types of poisoning and to increase heart rate, but it is not indicated for opioid overdose. Vitamin K (D) is used to treat bleeding disorders by promoting blood clotting and has no role in opioid overdose reversal.

Correct Answer: C

Rationale: Rationale: 1. Sitagliptin is a dipeptidyl peptidase-4 (DPP-4) inhibitor. 2. DPP-4 enzyme breaks down incretin hormones like GLP-1. 3. By inhibiting DPP-4, sitagliptin increases incretin hormone levels. 4. Incretin hormones stimulate insulin release and inhibit glucagon. 5. Thus, sitagliptin indirectly increases insulin secretion. Summary: A: Incorrect - Sitagliptin indirectly increases insulin secretion. B: Incorrect - Sitagliptin does not affect glucose absorption. D: Incorrect - Sitagliptin does not increase renal glucose excretion.