Nasonex cannot be purchased Over the Counter (OTC), that is, without a prescription. The active ingredient in Nasonex, mometasone furoate, belongs to a category of drugs called corticosteroids. Corticosteroids are
used for a wide variety of conditions ranging from arthritis to irritable bowel syndrome (IBS), and they come in many different dosage forms. Because these drugs work by acting on the immune system, there is always an associated risk of negative immunological side effects, especially with patients who have a decreased ability to fight infections as a result of another condition. Therefore, it is important for physicians to evaluate patients on a case by case basis in order to determine whether they are good candidates for corticosteroids. Additionally, nasal sprays such as Nasonex require specific usage instructions that are best described by physicians to their patients in person. These are some of the primary reasons that Nasonex is only available by prescription. Sources: NIH, drugs.com, Drug Information Handbook (15th Edition, 2007-2008), personal experience as a certified pharmacy technician.