PSA PSA Therapeutic Drug Monitoring 2

Question 1

A patient on theophylline for COPD has a level of 22 mcg/mL (therapeutic 10–20 mcg/mL). Which symptom is most consistent with theophylline toxicity?

Accepted Answer

Seizures

Answer

Theophylline toxicity can cause seizures, tachycardia, and arrhythmias, with seizures being a serious manifestation at supratherapeutic levels.

Question 2

Which condition would most likely increase cyclosporine blood levels and require downward dose adjustment?

Accepted Answer

Co-administration of fluconazole

Answer

Fluconazole inhibits CYP3A4, reducing cyclosporine metabolism and increasing blood levels, necessitating dose reduction.

Question 3

For patients on warfarin, INR is used as a surrogate for TDM. A patient with atrial fibrillation has an INR of 4.8 (target 2.0–3.0). What is the most appropriate action if there is no active bleeding?

Accepted Answer

Hold warfarin and recheck INR in 1–2 days

Answer

For a supratherapeutic INR without active bleeding, holding warfarin and rechecking in 1–2 days is the standard approach.

Question 4

Which of the following best describes why TDM for tacrolimus uses whole blood rather than serum?

Accepted Answer

Tacrolimus concentrates extensively in red blood cells

Answer

Tacrolimus binds extensively to erythrocytes, making whole blood the appropriate matrix for accurate TDM.

Question 5

A patient on methotrexate for rheumatoid arthritis has elevated liver enzymes. What monitoring parameter is specifically recommended to prevent methotrexate hepatotoxicity?

Accepted Answer

Liver function tests and CBC at regular intervals

Answer

Regular liver function tests and CBC are recommended for patients on methotrexate to detect hepatotoxicity and myelosuppression early.

(PSA) Prescribing Safety Assessment Practice Test

(PSA) Prescribing Safety Assessment Practice Test

PSA PSA Therapeutic Drug Monitoring 2