NAPLEX Question of the Week: Of Storage and Stability

How long can I store this at room temperature? How about refrigerated? These are common questions from patients received antibiotic suspensions which "constitutes" our question of the week.

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Which of the following correctly matches its storage and stability after reconstitution? Select all that apply.

A. Amoxicillin suspension – 7 days at room temperature or refrigerated

B. Amoxicillin/clavulanate suspension – 10 days refrigerated

C. Azithromycin immediate release suspension – 10 days at room temperature

D. Cefdinir suspension – 10 days refrigerated

E. Clindamycin solution – 14 days at room temperature



Answer with rationale:

The correct answers are B, C, and E.

As pharmacists, it is essential to know the storage and stability of medications after reconstitution, as they are important counseling points when dispensing to patients. Each formulation has specific recommendations and you should consult the package insert for detailed storage and stability information.

Answer A is incorrect because amoxicillin suspension is stable for 14 days at room temperature or refrigerated. Refrigeration is often preferred, and can sometimes taste better for pediatric patients when stored in the refrigerator. Unit-dose antibiotic oral syringes are stable at room temperature for at least 72 hours.

Answer B is correct. Amoxicillin/clavulanate suspension should be stored in the refrigerator and discarded after 10 days. Unit-dose antibiotic oral syringes are stable under refrigeration for 24 hours.

Answer C is correct. Azithromycin immediate release suspension (Zithromax) can be stored at room temperature (41°F to 86°F) and should be discarded after 10 days. However, it is important to note that there are different instructions for azithromycin extended release suspension (Zmax). Package insert for Zmax recommends storing the suspension at 25°C (77°F) with excursions permitted to 15°C to 30°C (59°F to 86°F). The suspension should not be refrigerated, and it should be consumed within 12 hours following reconstitution.

Answer D is incorrect because cefdinir suspension should be stored at room temperature and discarded after 10 days.

Answer E is correct. Clindamycin solution should be stored at room temperature for up to 2 weeks (14 days) after reconstitution. It should not be refrigerated as the solution will thicken.

Christopher M. Bland

Clinical Professor, University of Georgia College of Pharmacy

Dr. Christopher M. Bland is a Clinical Professor at the University of Georgia College of Pharmacy at the Southeast GA campus in Savannah, GA. Dr. Bland has over 20 years of academic and clinical experience in a number of clinical areas. He is a Fellow of both the Infectious Diseases Society of America as well as the American College of Clinical Pharmacy. He is co-founder of the Southeastern Research Group Endeavor, SERGE-45, with over 80 practitioners across 14 states involved. Dr. Bland serves as Associate Editor for the NAPLEX Review Guide 4th edition as well as Editor-In-Chief for the Question of the Week. He has provided live, interactive reviews for more than 10 Colleges/Schools of Pharmacy over the course of his career.