What is the maximal response a drug can produce?

Correct Answer: C

Rationale: Efficacy refers to the maximal response a drug can produce, regardless of the dose. It is a measure of how well a drug can produce its desired effect. Potency, on the other hand, refers to the amount of drug required to produce a specific effect and is not related to the maximal response. An agonist is a drug that binds to and activates a receptor. Bioavailability is the fraction of the administered dose of a drug that reaches the systemic circulation.

Correct Answer: D

Rationale: The loading dose of a drug required to reach an initial target blood concentration is based on the volume of distribution (Vd) of the drug. The volume of distribution represents the theoretical volume that would be necessary to contain the total amount of the administered drug at the same concentration as in the blood plasma. The loading dose is calculated by multiplying the target blood concentration by the volume of distribution of the drug. This initial dose helps to rapidly achieve the desired drug concentration in the body, especially when a drug has a long half-life or when steady-state levels need to be reached more quickly. Understanding the volume of distribution of a drug is crucial in dosage calculation to ensure therapeutic efficacy and avoid potential toxicity.

Correct Answer: D

Rationale: Acetylcysteine is the antidote for acetaminophen (paracetamol) overdose. Acetaminophen overdose can lead to hepatic necrosis, and acetylcysteine is effective in preventing or reversing this hepatotoxicity. It works by replenishing depleted hepatic stores of glutathione, which is essential for detoxifying the reactive metabolite of acetaminophen. This helps to protect the liver cells from damage caused by the toxic metabolite of acetaminophen. Naloxone, vitamin K, warfarin, and diphenhydramine are not effective in reversing the hepatic necrosis caused by paracetamol overdose.

Correct Answer: B

Rationale: The common side effects of amitriptyline (Elavil) include constipation and dry mouth. Increasing fluid intake can help alleviate these symptoms. Adequate hydration can aid in promoting bowel regularity and relieving dry mouth. It is important for the nurse to give the patient instructions to increase their fluid intake to manage these side effects rather than immediately discontinuing the medication or requesting a change in antidepressants. If the constipation and dry mouth persist or worsen despite increasing fluid intake, then the provider may need to be notified for further evaluation and management.

Correct Answer: C

Rationale: Flulike syndrome, characterized by fever, chills, fatigue, and muscle aches, is a common side effect of interferon alfa-2a. This occurs because the drug stimulates the immune system, mimicking the body's response to a viral infection. While gastrointestinal symptoms may occur, they are less common than flulike syndrome. Interferon alfa-2a does not typically cause an increase in white or red blood cells. The nurse should educate the patient about managing flulike symptoms, such as using antipyretics and staying hydrated.