Pediatric Antibiotic, a Warfarin Interaction, and a Request to Change the Dosage Form
A mother brings her 6-year-old to the pharmacy with an electronic prescription for azithromycin 200 mg/5 mL, "5 mL on day 1, then 2.5 mL daily on days 2 through 5," quantity 30 mL, no refills, from a pediatrician 90 minutes away. The child takes warfarin daily for a history of a cardiac thrombus. The pharmacy has the prescribed suspension in stock. The mother says the child vomits every suspension and asks the pharmacist to "just give the chewable tablets instead." The prescription contains the prescriber's name, address, and NPI, the patient's name and address, the date, drug, strength, quantity, directions, and refill information. The prescriber's office is closed for lunch, and the family leaves for a two-week trip tomorrow morning. The pharmacist must decide whether to dispense as written, change the dosage form, and what to tell the mother about the warfarin.
1. Does the prescription contain what North Carolina requires, and may the pharmacist substitute chewable tablets?
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The prescription contains the required elements: patient name and address, drug name and strength, quantity, directions, date, prescriber name and address, and refill information. An NPI is useful but is not a legal prerequisite for a noncontrolled prescription. A pharmacist may clarify an ambiguous order with the prescriber, but cannot change the dosage form on her own. Chewable tablets are a different product, so that is a therapeutic substitution requiring a new prescription or documented prescriber authorization. With the office at lunch and the family traveling, the pharmacist should try alternate contact numbers, document the attempts, and either dispense the suspension as written after counseling or hold the prescription. She should not switch products and annotate the original prescription as if it covered tablets.
2. How should the pharmacist handle the warfarin interaction and the child's vomiting?
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Azithromycin can potentiate warfarin; case reports describe rising INR and bleeding. The pharmacist should counsel the mother about bleeding signs-bruising, dark urine, nosebleeds, unusual fatigue-and advise that an INR be checked during or shortly after the course. The interaction is not a reason to withhold a needed antibiotic, but it is a reason to counsel, notify the prescriber, and document. Vomiting is a separate problem: if the child cannot retain the suspension, the prescribed course may fail, which is another reason to reach the prescriber about an alternative. If the prescriber authorizes tablets, the pharmacist must obtain a new prescription for that product and document who authorized it, when, and what was said. The pharmacist should not let the travel deadline push her into an unauthorized change.
3. What should be documented and what must appear on the label?
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Document the prescription as received, the counseling given (including the warfarin interaction and bleeding precautions), the contact attempts with the prescriber, and any authorization for a different product. The label should include the pharmacy name and address, prescription number, date filled, patient name, prescriber, drug name and strength, quantity, directions, and "shake well," along with storage instructions and a beyond-use or expiration date consistent with labeling rules. The patient profile should flag the warfarin interaction so future pharmacists see it. If the prescriber later changes the order to tablets, document the new prescription and do not overwrite the original record. Good records let the pharmacist show that the decision was deliberate and that the mother was warned about both the infection and the bleeding risk.