An 83-year-old man has a 2-month history of akinesia, rigidity, and tremor. He has been taking a drug for the past 7 years to control severe behavioral and psychiatric symptoms associated with dementia, Alzheimer type. This adverse effect is most likely mediated through which of the following?

Correct Answer: B

Rationale: The symptoms (akinesia, rigidity, tremor) suggest drug-induced parkinsonism, a common side effect of antipsychotics used for behavioral symptoms in Alzheimer’s dementiThese drugs (e.g., haloperidol) exert antidopaminergic effects by blocking D2 receptors in the nigrostriatal pathway, mimicking Parkinson’s disease. Anticholinergic effects typically relieve parkinsonism, not cause it. GABA downregulation or upregulation (F) relates to sedation or seizures, not these motor symptoms. Norepinephrine or serotonin (E) reuptake inhibition is unrelated to parkinsonism.

Correct Answer: A

Rationale: Digoxin slows heart rate via vagal stimulation and AV node inhibition. A pulse of 53 beats/minute (bradycardia) is below the typical threshold (<60 bpm) for holding the dose, making the first action to prevent toxicity (e.g., arrhythmias). Notifying the charge nurse or provider follows, and administering risks harm. Note: Answer key says (c), but is the priority per nursing protocol.

Correct Answer: C

Rationale: The appropriate alimentary route of administration when passage of drugs through the liver is to be minimized is option C) Rectal. When a drug is administered rectally, it bypasses the liver and enters the bloodstream directly through the rectal mucosa, thus avoiding the first-pass metabolism in the liver. This can be beneficial for drugs that are extensively metabolized in the liver or those that may cause liver toxicity. Option A) Oral administration is incorrect in this scenario because drugs taken orally pass through the liver before entering the systemic circulation, which can result in significant metabolism by the liver. Option B) Transdermal administration involves drug absorption through the skin and is not directly related to liver metabolism. Option D) Intraduodenal administration involves delivering drugs directly into the duodenum, which does not bypass the liver and can still result in first-pass metabolism. In an educational context, understanding the different routes of drug administration is crucial for healthcare professionals to make informed decisions about the most appropriate route based on the pharmacological effects desired and the specific needs of the patient. Knowledge of how drug metabolism occurs in the liver and the impact of first-pass metabolism can help in optimizing drug therapy for clients across the lifespan.

Correct Answer: A

Rationale: The correct answer is A) Concentration of a substance in plasma when calculating the volume of distribution (Vd). When calculating Vd, the concentration of a substance in the plasma is crucial because Vd is a pharmacokinetic parameter that helps determine how a drug is distributed throughout the body. It indicates the theoretical volume that would be necessary to contain the total amount of drug in the body at the same concentration observed in the plasma. Therefore, the concentration in plasma directly relates to the Vd calculation. Option B) Concentration of substance in urine is incorrect because Vd is not determined based on the concentration of the substance in urine, but rather in plasma, as it reflects the distribution of the drug within the body. Option C) Therapeutic width of drug action is incorrect as it refers to the range of drug concentrations in the body that produce the desired therapeutic effect. It is not directly related to the calculation of Vd. Option D) A daily dose of drug is incorrect as it is related to dosing calculations and not to the calculation of Vd, which is specifically based on the concentration of the substance in plasma. Understanding how to calculate pharmacokinetic parameters like Vd is essential for healthcare professionals to optimize drug therapy and ensure safe and effective treatment for clients across the lifespan. By grasping these concepts, healthcare providers can make informed decisions about drug dosing, monitoring, and adjustments to achieve desired therapeutic outcomes while minimizing adverse effects.

Correct Answer: B

Rationale: In the case of liver disorders accompanied by a decline in microsomal enzyme activity, the duration of action of some drugs is **enlarged**. This is because microsomal enzymes, primarily found in the liver, play a crucial role in metabolizing many drugs. When their activity is reduced due to liver dysfunction, the breakdown of drugs slows down, leading to a longer duration of action. Option A) **Decreased** is incorrect because a decline in microsomal enzyme activity would not speed up the breakdown of drugs, resulting in a decreased duration of action. Option C) **Remained unchanged** is incorrect because if the liver's ability to metabolize drugs is compromised, it would impact the duration of action of drugs, making this option inaccurate. Option D) **Changed insignificantly** is incorrect because a decline in microsomal enzyme activity can significantly alter the pharmacokinetics of drugs, affecting their duration of action. Understanding the impact of liver disorders on drug metabolism is vital for healthcare professionals to ensure appropriate dosing and monitoring of pharmacological treatments in clients across the lifespan. This knowledge is crucial in preventing adverse effects and optimizing therapeutic outcomes, especially in vulnerable populations such as the elderly or pediatric patients.