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The client receives 200 mg of a medication on a consistent schedule. How much drug is in the body at 4 half-lives?

387.5

375

393.8

350

Answer and Explanation

The Correct Answer is B

Here's the process for calculating the drug concentration after multiple half-lives:

First half-life: After 1 half-life, 50% of the original dose remains in the body.

200 mg x 0.50 = 100 mg remains after 1 half-life.

Second half-life: After 2 half-lives, 50% of the remaining drug will be eliminated.

100 mg x 0.50 = 50 mg remains after 2 half-lives.

Third half-life: After 3 half-lives, 50% of the remaining drug will be eliminated again.

50 mg x 0.50 = 25 mg remains after 3 half-lives.

Fourth half-life: After 4 half-lives, 50% of the remaining drug will be eliminated once more.

25 mg x 0.50 = 12.5 mg remains after 4 half-lives.

Now, we need to sum up the amount of drug remaining in the body at each half-life:

After 4 half-lives, there are 12.5 mg left from the original dose.

Total drug in the body after 4 half-lives = 200 mg - 12.5 mg = 375 mg.

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Correct Answer is D

Explanation

A) The ammonia level has decreased each day starting the lactulose: While a decrease in ammonia levels is an important indicator of improvement in hepatic encephalopathy, it is not the best assessment of the therapeutic response to lactulose. The goal of lactulose therapy is to reduce ammonia levels, but the most direct evaluation of therapeutic effect is related to the client's mental status, not just laboratory results.

B) The liver enzymes AST and ALT have decreased to normal levels: Liver enzyme levels such as AST (aspartate aminotransferase) and ALT (alanine aminotransferase) are important indicators of liver function, but they do not directly reflect the effectiveness of lactulose in treating hepatic encephalopathy. These enzymes may improve as liver function improves, but they are not the most immediate or specific indicator of lactulose’s therapeutic effect.

C) The client is having 5-6 soft, non-formed stools each day: Lactulose works by drawing water into the bowel to promote stool softening and increase bowel movements, which can help lower ammonia levels in the body. While frequent soft stools can be an effect of lactulose, this is not the best measure of therapeutic response in hepatic encephalopathy. The primary goal is improvement in the client's mental status, not just bowel function.

D) The client is awake, alert, and oriented to their environment: The best assessment of the therapeutic response to lactulose is the improvement in the client’s mental status. Lactulose works by reducing the absorption of ammonia from the gastrointestinal tract, which is responsible for the cognitive impairments seen in hepatic encephalopathy. If the client is awake, alert, and oriented, this indicates that lactulose is effectively reducing the ammonia levels and improving the neurological status of the client, making it the most appropriate assessment.

A. True B. False

Correct Answer is A

Explanation

CYP 450 enzymes are responsible for the metabolism of many drugs. Smoking can induce certain CYP 450 enzymes, particularly CYP1A2, which leads to an increase in the metabolism of drugs that are substrates of this enzyme. When a person begins smoking, the induction of these enzymes can cause drugs to be metabolized more quickly, which typically results in lower drug levels in the body. However, the statement asks whether the level of medication will increase in this client, and since smoking induces enzyme activity, it would typically lead to decreased, not increased, drug levels. However, in the context of drug-drug interactions and other metabolic pathways, the metabolism rate could be altered in ways that might increase or affect the therapeutic response.

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The client receives 200 mg of a medication on a consistent schedule. How much drug is in the body at 4 half-lives?

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Naxlex Comprehensive Predictor Exams

The nurse is caring for client with liver failure admitted with hepatic encephalopathy, Lactulose is ordered Q2 hours. What assessment finding should the nurse use to best evaluate therapeutic response of the medication?

Correct Answer is D

Explanation

A client currently prescribed a medication highly metabolized by the CYP 450 recently began smoking due to a stressful life event. True or False: The level of medication will increase in this client.

Correct Answer is A

Explanation

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