Question 28

Patients taking narrow therapeutic index drugs may require monitoring because small differences in blood concentration could cause serious adverse reactions.

Narrow therapeutic index drugs have a small margin between therapeutic and toxic doses, making it crucial to monitor blood concentrations to avoid serious adverse reactions.

A) drug-disease contraindications.

Drug-disease contraindications refer to situations where a drug should not be used due to the presence of a specific disease. While contraindications are important, they do not directly relate to the monitoring of blood concentration levels in patients taking narrow therapeutic index drugs.

B) chemical incompatibilities.

Chemical incompatibilities involve reactions between drugs that can lead to ineffective treatment or harm. However, this concept does not pertain to the monitoring of blood concentrations of narrow therapeutic index drugs, as it focuses on interactions rather than concentration-related effects.

C) serious adverse reactions.

Serious adverse reactions are a significant concern for patients on narrow therapeutic index drugs due to their limited therapeutic range. Even slight variations in blood concentration can lead to severe side effects or toxicity, which is why monitoring is essential.

D) anaphylactic shock.

Anaphylactic shock is a severe allergic reaction that can occur with some medications, but it is not specifically linked to the blood concentration of narrow therapeutic index drugs. Monitoring is more focused on preventing serious adverse reactions related to toxicity rather than allergic responses.

Conclusion

The correct answer is C, as monitoring is critical for patients on narrow therapeutic index drugs due to the risk of serious adverse reactions from minor fluctuations in drug levels. Options A, B, and D do not address the specific relationship between drug concentration and adverse outcomes, highlighting the importance of careful monitoring in this patient population.