<P> An ill - defined third category of substances is products having over-the - counter status from the FDA while being simultaneously subject to other restrictions on sale . While they are legally classified as OTC drugs, they are typically stored behind the counter and are sold only in stores that are registered with their state . They may be unavailable in convenience and grocery stores that stock other non-restricted OTC medications . </P> <P> For example, many drugstores have moved products containing pseudoephedrine, an OTC product, into locations where customers must ask a pharmacist for them . A prescription is not required; the change has been made in an effort to reduce methamphetamine production . Since the passage of the Illinois Methamphetamine Precursor Control Act and the subsequent federal Combat Methamphetamine Epidemic Act of 2005, the purchase of pseudoephedrine is restricted . Sellers of pseudoephedrine must obtain and record the identity of the purchaser and enforce quantity restrictions . Some states may have more stringent requirements (such as Oregon, where a medical prescription is required to purchase any quantity of pseudoephedrine). After initial attempts to control methamphetamine use (by requiring documentation of sale with government issued ID as well as limits on the quantity an individual could purchase) failed to realize meaningful reductions in methamphetamine use and production, Mississippi passed House Bill 512 in the State Senate on February 2, 2010 "to require a prescription from a licensed medical professional to purchase over-the - counter medicines with pseudoephedrine, ephedrine, or any other precursor chemical that can readily and illicitly be converted into methamphetamine, Methcathinone or any active / scheduled analogs of Phenylethylamines / amphetamine ." However, products containing the substance are still OTC in most states, since no prescription is required . </P> <P> A similar regulation applies to some forms of emergency contraception . The FDA considers them to be OTC substances for females 17 or over but prescription drugs for younger women . To enforce the restriction and to provide counseling and education on proper use, an agreement between the manufacturer and the FDA requires the drugs are stored behind the pharmacy counter . Women may obtain the medication without a prescription after providing proof of age to pharmacy staff and receiving any necessary patient education . </P> <P> Furthermore, some Schedule V controlled substances may be classified as OTC products in certain states . Such drugs are sold without a prescription but are subject to record - keeping rules and quantity and / or age restrictions, and they must be dispensed by a pharmacy . </P>

Who has the authority to decide if a drug is marketed as an otc or prescription-only product