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Overview of Over-the-Counter Drugs

by Daniel A. Hussar, PhD

Over-the-counter (OTC) drugs are those available without a prescription.

OTC drugs enable people to relieve many annoying symptoms and to cure some diseases simply and without the cost of seeing a doctor. However, safe use of these drugs requires knowledge, common sense, and responsibility.

In addition to the substances such as aspirin and acetaminophen that people typically think of as OTC drugs, many other commonly available products are considered OTC drugs by the federal Food and Drug Administration (FDA). Some toothpastes, some mouthwashes, some types of eye drops, wart removers, first aid creams and ointments that contain antibiotics, and even dandruff shampoos are considered OTC drugs. Some OTC drugs were originally available only by prescription. After many years of use under prescription regulation, drugs with excellent safety records may be approved by the FDA for over-the-counter sale. The analgesic ibuprofen and the indigestion remedy famotidine are examples of such drugs. Often, the OTC version has a substantially lower amount of active ingredient in each tablet, capsule, or caplet than does the prescription drug. When establishing appropriate doses of OTC drugs, manufacturers and the FDA try to balance safety and effectiveness.

OTC drugs are not always better tolerated than similar prescription drugs. For example, the OTC sleep aid diphenhydramine is neither as effective nor as safe, especially for older people, as many prescription sleep aids.

Historical Background

At one time, most drugs were available without a prescription. Before the FDA existed, just about anything could be put in a bottle and sold as a sure-fire cure. Alcohol, cocaine, marijuana, and opium were included in some OTC products without notification to users. The Food, Drug, and Cosmetic (FD&C) Act, enacted in 1938, gave the FDA some authority to issue regulations, but the act did not provide clear guidelines as to which drugs could be sold by prescription only and which could be sold over the counter.

An amendment to the FD&C Act in 1951 attempted to clarify the difference between OTC and prescription drugs and to deal with issues of drug safety. Prescription drugs were defined as compounds that could be habit forming, toxic, or unsafe for use except under a doctor's supervision. Anything else could be sold over the counter.

As noted by an amendment to the FD&C Act of 1962, OTC drugs were required to be both effective and safe (see Drug Effectiveness and Safety). However, determining effectiveness and safety can be difficult. What is effective for one person may not be for another, and any drug may cause unwanted side effects (also called adverse effects, adverse events, or adverse drug reactions—see Overview of Adverse Drug Reactions). There is no organized system for reporting the side effects of OTC drugs. Consequently, the FDA and drug manufacturers have virtually no way of knowing how common or serious the side effects are.

Safety Considerations

Safety is a major concern when the FDA considers reclassifying a prescription drug as OTC. Most OTC drugs—unlike health foods, dietary supplements (including medicinal herbs—see Overview of Medicinal Herbs and Nutraceuticals) and complementary therapies (see Overview of Complementary and Alternative Medicine)—have been studied scientifically and extensively. However, all drugs have benefits and risks, and some degree of risk has to be tolerated if people are to receive a drug's benefits. Defining an acceptable degree of risk is a judgment call.

Safety depends on using a drug properly. For OTC drugs, proper use often relies on consumer self-diagnosis, which leaves room for error. For example, most headaches are not dangerous, but in rare cases, a headache is an early warning of a brain tumor or hemorrhage. Similarly, what seems like severe heartburn may signal an impending heart attack. Ultimately, people must use common sense in determining when a symptom or ailment is minor and when it requires medical attention and consult a doctor if they are unsure.

People who purchase OTC drugs should read and follow the instructions carefully. Because different formulations—such as immediate-release and controlled-release (slow-release) formulations—may have the same brand name, the label should be checked each time a product is purchased, and the dosage should be noted. Assuming that the dosage is the same is not safe. Also, different formulations with the same brand name may have different ingredients, so checking the ingredients on the label is important. For example, there are several dozen different Tylenol formulations with a vast array of ingredients. Some Maalox products contain aluminum and magnesium hydroxides, while others contain calcium carbonate. When selecting a product, people should read the label carefully to determine which product is most appropriate for their particular problem. Labels on OTC drugs, which are required by the FDA, can help people understand a drug's benefits and risks as well as how to use the drug correctly. People should ask a pharmacist if they have any questions about an OTC product.

Often, the labels of OTC drugs do not list the full range of possible side effects. As a result, many people assume that these drugs have few, if any, side effects. For example, the package insert for one analgesic cautions people not to take the drug for more than 10 days for pain. However, the possible serious side effects that can occur with long-term use (such as life-threatening bleeding from the digestive tract) are not mentioned—not on the box, bottle, or package insert. Consequently, people with chronic pain or inflammation may take the drug for a long time without realizing that such use could lead to serious problems.

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Drugs Mentioned In This Article

  • Generic Name
    Select Brand Names
  • No US brand name
  • ADVIL, MOTRIN IB
  • PEPCID
  • TYLENOL