According to USP <1079> Good Storage and Distribution Practices, the most accurate source for determining proper storage conditions of a medication is the manufacturer's label or package insert, which contains specific temperature and humidity requirements (e.g., refrigeration, protection from light). This information is required by FDA labeling regulations and is essential for maintaining drug stability and potency.

Additionally, the Mosby’s Pharmacy Technician Review Guide states:

“Storage requirements should always be verified using the product’s official labeling or manufacturer’s monograph, as these contain validated stability data.”