Question 43

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

Monitoring is essential for patients on narrow therapeutic index drugs due to the potential for small variations in blood concentration to lead to serious adverse reactions, including toxicity or ineffectiveness.

A) Drug-disease contraindications

While drug-disease contraindications are important to consider when prescribing medications, they do not specifically relate to the blood concentration variations in narrow therapeutic index drugs. These contraindications are based on the patient's medical history and the drug's known effects, rather than fluctuations in drug levels.

B) Chemical incompatibilities

Chemical incompatibilities refer to the interactions between different drugs or substances that can lead to adverse effects. However, they do not directly relate to the monitoring of blood concentration levels in narrow therapeutic index drugs, making this option incorrect in the context of the question.

C) Serious adverse reactions

This option correctly identifies that small differences in blood concentration can lead to serious adverse reactions. Narrow therapeutic index drugs have a small margin between therapeutic and toxic doses, making close monitoring critical to avoid potentially harmful effects.

D) Anaphylactic shock

Anaphylactic shock is a severe allergic reaction that can occur with certain medications, but it is not specifically related to the blood concentration of narrow therapeutic index drugs. This option does not address the primary concern of monitoring these drugs, which is the risk of serious adverse reactions due to concentration changes.

Conclusion

The correct answer is C, as it directly addresses the risks associated with narrow therapeutic index drugs and the necessity for monitoring blood concentrations. Options A, B, and D are not relevant to the specific issue of concentration variability leading to adverse effects, emphasizing the importance of careful management in these cases.