A 38-year-old man has come into the urgent care center with severe hip pain after falling from a ladder at work. He says he has taken several pain pills over the past few hours but cannot remember how many he has taken. He hands the nurse an empty bottle of acetaminophen (Tylenol). The nurse is aware that the most serious toxic effect of acute acetaminophen overdose is which condition?

Correct Answer: C

Rationale: The correct answer is C: Hepatic necrosis. Acetaminophen overdose can lead to severe liver damage due to the production of a toxic metabolite. This metabolite depletes glutathione stores in the liver, leading to oxidative stress and hepatocellular injury. Hepatic necrosis can progress to acute liver failure, which can be life-threatening. Tachycardia (choice A) and central nervous system depression (choice B) are not the most serious toxic effects of acetaminjson overdose. Nephropathy (choice D) is not a common consequence of acetaminophen overdose compared to hepatic necrosis.

Correct Answer: D

Rationale: The correct answer is D: Dysrhythmias. Antidysrhythmic drugs can potentially cause new or worsened dysrhythmias as an adverse effect due to their mechanism of action on cardiac electrophysiology. This can lead to serious complications such as ventricular tachycardia or fibrillation. A: Deficiency of fat-soluble vitamins - Antidysrhythmic drugs do not typically cause this adverse effect. B: Hyperkalemia - While some drugs may affect potassium levels, dysrhythmias are a more direct and common adverse effect of antidysrhythmic drugs. C: Heart failure - While some drugs may exacerbate heart failure in certain situations, dysrhythmias are a more immediate concern with antidysrhythmic therapy.

Correct Answer: B

Rationale: The correct answer is B: A short-acting beta2 agonist such as albuterol (Proventil). In an acute asthma attack, bronchodilation is crucial for quick relief. Short-acting beta2 agonists like albuterol act rapidly to dilate the airways, providing immediate relief of symptoms. Anticholinergics like ipratropium (A) are also bronchodilators but are not as effective for acute exacerbations. Long-acting beta2 agonists like salmeterol (C) are used for long-term maintenance, not for immediate relief. Corticosteroids like fluticasone (D) are important for reducing airway inflammation but are not the first-line treatment for acute attacks.

Correct Answer: A

Rationale: The correct answer is A: Renal tubules. Biological barriers are structures that prevent the entry of harmful substances into the body. Renal tubules are not considered a biological barrier as they are involved in the filtration and reabsorption of substances within the body, rather than acting as a physical barrier. Cell membranes, capillary walls, and the placenta are all examples of biological barriers as they selectively control the passage of substances into and out of cells, tissues, and organs to maintain homeostasis. Therefore, the renal tubules do not fit the criteria of a biological barrier, making option A the correct answer.

Correct Answer: C

Rationale: The correct answer is C, Abstinence Syndrome. This term refers to the occurrence of psychological and somatic disturbances when a drug is suddenly discontinued after prolonged use. Tachyphylaxis (A) is the rapid development of tolerance to a drug. Sensibilization (B) is the opposite of tolerance, where increased sensitivity to a drug occurs over time. Idiosyncrasy (D) is an unexpected or unusual reaction to a drug. In this scenario, the situation describes the consequences of stopping the drug, aligning with the definition of Abstinence Syndrome.