It seems extremely obvious that prescription drugs require a physician’s order (i.e., prescription) for patients to receive them and that OTC drugs are those that may be purchased without a prescription. Nonetheless, there are numerous complicating factors. First, prescription drugs can be bought OTC in many countries. Second, there is a third category of drugs in some countries, often referred to as transition class drugs or third category drugs. Pharmacists dispense these drugs when they are convinced that the patient or requester has a legitimate need. The concept behind the third category is widely supported by pharmacists and pharmacist organizations in the United States but is rarely supported by physicians, pharmaceutical companies, or their trade associations. The notion of “learned intermediary” is used to encourage acceptance of this third class of drugs. The learned intermediary is the professional interface between a drug and the consumer or patient—the physician for prescription drugs. Any healthcare provider can supply information to patients for OTC drugs. However, only a physician can be a “learned intermediary” and this only applies to prescription drugs (Peter Barton Hutt, personal communication, 2008). Labeling should provide complete educational information telling patients how and when to use the product.

Lastly, some drugs are sold both by prescription and as OTC products in a single country, although the dosage may differ (e.g., in the United States, 200-mg ibuprofen tablets are sold OTC, whereas 400-mg tablets are sold only with a prescription).

Another definitional issue applies to the different types of OTC drugs in Europe. Semi-ethical drugs are sold OTC and are reimbursed by the government (where applicable) as if they were prescription drugs. Registered OTC drugs are sold OTC but are not reimbursed by the government. Mass market drug products include vitamins and minerals, and nonregistered drugs that include homeopathic and herbal drugs; both categories are sold widely in Europe. OTC issues in Europe have been discussed by Dudley (1992).

The major reason to consider this switch is the certain loss of patent protection on a commercially important drug and the eventual generic competition that will rapidly erode sales of that drug. In another case, a patented drug that is showing declining sales often can be revived once it is sold OTC. If sales are stable or increasing on a prescription drug that has no patent protection, the OTC market might still be much larger than the prescription market. Another reason to switch to OTC status is that the drug might complement existing OTC products or product lines. Table 97.1 lists other potential reasons for making the OTC switch.

There is a theoretical possibility in the United States that a drug switched to OTC status can be granted a period of marketing exclusivity by the Food and Drug Administration (FDA). This would be based on submitting new information and data that are pertinent to the switch that were not presented or relied on for obtaining the prescription indication.

In evaluating the OTC conversion issue, some potentially negative consequences must also be considered.

In general, prescription-to-OTC switching has been less successful in Europe than in the United States. This primarily relates to different reimbursement policies for patient visits to physicians. In the United States, patients often save money by purchasing OTC drugs in lieu of paying for an office visit to a physician. This is not common in most European countries because patients do not generally pay (or only pay a small amount) for visits to personal physicians. Other factors that complicate the European OTC system are country-specific cultures, traditions, and distribution systems for OTC drugs. Experiences with switching large numbers of products in Denmark are discussed by Raith (1992).

A few questions must be addressed prior to reaching a decision to convert a prescription drug to OTC status.