Medication A has a half-life of 3 hours. If the nurse administers a single dose of 400 mg of medication A, how much will excrete from the patient’s body after 12 hours?
100 mg
375 mg
150 mg
25 mg
The Correct Answer is D
Choice A Reason:
To determine how much of the medication remains in the body after a certain period, we need to understand the concept of half-life. The half-life of a medication is the time it takes for the concentration of the drug in the bloodstream to reduce by half. For Medication A, the half-life is 3 hours. After 12 hours, which is four half-lives, the amount of medication remaining can be calculated step by step.
Choice B Reason:
Let’s break down the calculation. Initially, the patient receives 400 mg of Medication A. After the first half-life (3 hours), the amount of medication remaining is 400 mg ÷ 2 = 200 mg. After the second half-life (6 hours), the amount remaining is 200 mg ÷ 2 = 100 mg. After the third half-life (9 hours), the amount remaining is 100 mg ÷ 2 = 50 mg. Finally, after the fourth half-life (12 hours), the amount remaining is 50 mg ÷ 2 = 25 mg. Therefore, 375 mg is not a correct answer.
Choice C Reason:
Similarly, 150 mg is not correct. As shown in the detailed calculation, the amount of medication decreases by half every 3 hours. After 12 hours, the remaining amount is 25 mg, not 150 mg. This choice does not align with the half-life calculation.
Choice D Reason:
This is the correct answer. The step-by-step calculation shows that after 12 hours, which is equivalent to four half-lives, the amount of Medication A remaining in the patient’s body is 25 mg. This demonstrates the principle of half-life and how the concentration of a drug decreases over time.
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is A
Explanation
Choice A: Metabolic Acid Deficit (Metabolic Alkalosis)
Vomiting or continuous nasogastric suctioning leads to the loss of gastric contents, which are rich in hydrochloric acid (HCl)1. This loss results in a decrease in the body’s acid levels, leading to a condition known as metabolic alkalosis2. Metabolic alkalosis is characterized by an increase in blood pH due to the loss of hydrogen ions (H+) and an increase in bicarbonate (HCO3-) levels. This condition can cause symptoms such as muscle twitching, hand tremors, and light-headedness.
Choice B: Carbonic Acid Excess (Respiratory Acidosis)
Carbonic acid excess, or respiratory acidosis, occurs when there is an accumulation of carbon dioxide (CO2) in the blood, leading to a decrease in blood pH3. This condition is typically caused by respiratory issues such as hypoventilation, chronic obstructive pulmonary disease (COPD), or severe asthma. It is not directly related to vomiting or nasogastric suctioning, which primarily affect the metabolic component of acid-base balance.
Choice C: Metabolic Acid Excess (Metabolic Acidosis)
Metabolic acidosis is characterized by a decrease in blood pH due to an accumulation of metabolic acids or a loss of bicarbonate. Common causes include renal failure, diabetic ketoacidosis, and severe diarrhea. Vomiting or nasogastric suctioning, which result in the loss of gastric acid, do not lead to metabolic acidosis but rather to metabolic alkalosis.
Choice D: Carbonic Acid Deficit (Respiratory Alkalosis)
Respiratory alkalosis occurs when there is a decrease in carbon dioxide levels in the blood, leading to an increase in blood pH. This condition is often caused by hyperventilation due to anxiety, fever, or high altitude. It is not related to the loss of gastric contents through vomiting or nasogastric suctioning, which primarily affect the metabolic component of acid-base balance.
Correct Answer is D
Explanation
Choice A Reason:
The prodromal stage refers to the period during which early symptoms of a disease appear but are not yet specific or severe. This stage is often associated with infectious diseases where initial symptoms like fever, malaise, and fatigue occur before more specific symptoms develop. In the context of HIV, the prodromal stage would not be applicable as it refers to the early symptomatic phase rather than a period without symptoms.
Choice B Reason:
Remission is a term used to describe a period during which the symptoms of a disease are reduced or disappear. This term is commonly used in the context of chronic diseases such as cancer or autoimmune disorders. For HIV, remission would imply a reduction in viral load and symptoms due to effective treatment, but it does not describe the asymptomatic phase following initial exposure.
Choice C Reason:
Exacerbation refers to the worsening or flare-up of symptoms in a chronic disease. This term is often used in conditions like asthma or multiple sclerosis where symptoms can become more severe periodically. In the context of HIV, exacerbation would describe periods where symptoms become more pronounced, not the asymptomatic phase after initial exposure.
Choice D Reason:
The latent stage, also known as the clinical latency stage or asymptomatic HIV infection, is the period after initial HIV exposure when the virus is present in the body but not causing any symptoms. During this stage, HIV continues to replicate at low levels, and the individual may not feel sick or show any signs of the disease. This stage can last for several years, especially with effective antiretroviral therapy.
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