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Question: Pharm

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You are seeing a 6 year old with 1 ½ weeks of cough, nasal congestion, and malaise. Initially, he seemed to be improving a bit, but now for the last 2 days he has a fever and worsened cough, post-tussive and spontaneous vomiting, as well as a new sore throat and conjunctival injection. His vital signs are: temperature is 38.2, HR 110, RR 32, and pulse ox 96% on room air. On exam he is nontoxic but has some crackles heard bilaterally. Your plan is to treat him with azithromycin for community-acquired pneumonia, pseudoephedrine during the day and diphenhydramine at night for his nasal congestion, and ondansetron for his vomiting. 

The pharmacist calls you to discuss potential interactions between which 2 medications you prescribed?


pemsou5_wp • June 20, 2023

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  1. Kelly June 25, 2023 - 8:18 pm Reply

    B) Azithromycin and ondansetron
    Both increase the QTc interval. They should be avoided in patients with known long QT syndrome, and caution must be observed when giving two medications that prolong QTc. Precautions might include pre-prescription ECG screening as well as ongoing ECG monitoring with prolonged courses. In this case, since ondansetron is symptomatic and not definitive therapy, if the child is able to stay adequately hydrated without use of ondansetron, it could be omitted. Medscape has a useful drug interaction checker

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