Which of the following best describes the role of compounding pharmacies?

Compounding pharmacies primarily focus on producing individualized medications tailored to meet the unique needs of patients. This can involve altering the strength of a medication, combining multiple medications into a single dose, or eliminating specific allergens or additives for patients who may be sensitive to them. Such customization is crucial for patients with specific health conditions, age-related needs, or those who require dosages that are not commercially available.

The other options don't accurately reflect the primary function of compounding pharmacies. While manufacturing large quantities of drugs is typically the role of large pharmaceutical manufacturers, compounding pharmacies operate on a smaller scale focused on personalization. Marketing over-the-counter medications is more aligned with retail pharmacies rather than compounding pharmacies, which usually emphasize prescription-based formulations. The distribution of controlled substances, while a function of pharmacies in general, is not specific to compounding and does not define their primary role. Thus, the best description of compounding pharmacies is the production of individualized medications for patients.