Over-The-Counter Drugs
(Ch. 14)


  • OVER-THE-COUNTER (OTC) DRUGS ARE A BIG BUSINESS IN THE UNITED STATES
    1. OTC drugs are those which are self-prescribed and self-administered for the relief of self-diagnosed illnesses
    2. The FDA estimates that consumers self-treat four times more health problems than doctors treat, often using OTC drugs
    3. Americans spend over $18 billion a year on OTC products
    4. The two biggest markets are for aspirin-like analgesics and for the collection of cough, cold, and flu products
    5. The 1962 Kefauver-Harrris amendment required that all drugs be evaluated for both safety and efficacy.
    6. The FDA reviews each active ingredient - in 1972, they divided OTC products into 26 classes and appointed an advisory panel for each class to decide for each ingredient whether there is evidence indicating that it is safe and effective for its purpose, and also to decide what sorts of claims could be made for that ingredient on the label
    7. The FDA classifies these as being "generally recognized as safe" (GRAS) and/or "generally recognized as effective" (GRAE)
    8. In 1985, the FDA began to publish "Tentative Final Monographs" on each class - to solicit comments from the public and drug companies before publishing Final Monographs - this has been an immense task.
    9. By 1992, only 34 of the proposed 71 monographs had become finalized (it's not clear whether the remaining Tentative Final Monographs are becoming more final or more tentative as the process continues)
    10. As advisory panels made tentative decisions, they were communicated to the manufacturers, who were encouraged to change their formulations
    11. In 1992, the US General Accounting Office released a critical report claiming that the FDA still didn't know exactly how many OTC products are being marketed and still couldn't guarantee that everything being sold is both safe and effective.
    12. By the 1990s the list of therapeutic classes had grown from 26 to over 80 (today the number of OTC products is still not known - perhaps more than 100,000)
    13. In 1997, the FDA proposed to create uniform standards for labels, with a minimum print size, topics in a consistent order (active ingredients, directions for use, warnings), with bold, bulleted headings, and make the language more understandable
    14. A drug is permitted for OTC sale unless, because of potential toxicity or for other reasons, it may be safely sold and used only under a prescription. Sometimes the only difference between an OTC product and a prescription product is the greater amount of active ingredient in each prescription dose. More often, prescription drugs are chemicals that are unavailable OTC.
    PSYCHOACTIVE OTC PRODUCTS
    1. The only OTC stimulant allowed by the FDA is caffeine; there are many "look-alikes" to resemble prescription stimulants, such as metamphetamine
    2. phenylpropanolamine (PPA) has a molecular structure similar to that of amphetamine and ephedrine is the only drug in weight-control products, the others pass off as "health foods". The recommended dose for appetite suppression is 75 mg per day. There is some concern about the safety of this dose, with the threat being increased blood pressure resulting from sympathetic stimulation
    3. A few years ago, most sleep aids contain small amounts of the antihistamine methapyrilene - then in 1979, it was reported that methapyrilene caused cancer in laboratory animals, so it was no longer GRAS.
    4. Today, most antihistamines are used as OTC sleep aids — diphenhydramine is the active ingredient in most products
  • ANALGESICS
    1. Two major classes of drugs are used to reduce pain or the awareness of pain: anesthetics and analgesics. The latter are compounds that reduce pain selectively without causing a loss of other sensations.
    2. The analgesics are divided into two groups: opiates and OTC internal analgesics (aspirin, acetaminophen, and ibuprofen)
    3. Placebos have also been effective in reducing pain (35% of patients in one study). It was found that placebos are most effective in reducing pain in stressful situations. Internal analgesics have shown to be more effective at therapeutic doses than placebos for certain kinds of pain
  • SALICYCLATES ARE THE MOST WIDELY USED CLASS OF INTERNAL ANALGESICS
    1. In 1859, salicylic acid was synthesized - the major difficulty is that it caused stomach discomfort. In 1898, acetylsalicylic acid was synthesized - - it provided relief from pain without stomach upset. The compound was tested, patented and released for sale in 1899 as Aspirin. Taken orally, aspirin is a more potent analgesic than salicylic acid, because it does not irritate the stomach as much and thus is absorbed more rapidly
    2. In 1915, the 5 gram (325 mg) white tablet stamped "Bayer" first appeared and aspirin became a nonprescription item
    3. Aspirin has three major therapeutic uses — to block somatic pain, as an antipyretic agent (reducing fever at the temperature-regulating area of the hypothalamus), and as an anti-inflammatory agent
    4. Some aspirin preparations have been buffered with additional ingredients meant to neutralize the acidity of aspirin. This has two effects: 1) to reduce stomach irritation, and 2) by moving the aspirin more rapidly into the intestine (faster absorption rate than the stomach), to produce faster relief
    5. The therapeutic dose for aspirin is generally considered to be in the range of 600 - 1,000 mg
    6. Aspirin also has some negative side effects such as: 1) increasing the bleeding time by inhibiting blood platelet aggregation, 2) inducing gastrointestinal bleeding, 3) Reyes syndrome affecting people under the age of 20, usually after they have had viral infections (overall mortality rate is ~25%). No one knows what causes Reyes syndrome (check with your physician), and 4) overdose poisonings.
    7. Aspirin modifies the the cause of pain. Prostaglandins are local hormones that are manufactured and released when cell membranes are distorted or damaged. The prostaglandins work on the ends of neurons that mediate pain in the injured areas. The prostaglandins sensitize the neurons to mechanical stimulation and to stimulation by two other local hormones histamine and bradykinin. Aspirin blocks the synthesis of the prostaglandins.
    8. As an antipyretic: specific prostaglandins act on the anterior hypothalamus to decrease heat dissipation through the normal procedures of sweating and the dilation of peripheral blood vessels. Aspirin blocks the synthesis of this prostaglandin
  • ACETAMENOPHEN AND IBUPROFEN
    1. Acetaminophen (aspirin-like analgesic and antipyretic) is as effective as aspirin in reducing pain as long as dosage limits are carefully observed, overuse can result in fatal liver damage
    2. Ibuprofen (aspirin-like analgesic and anti-inflammatory) is the ingredient in other new pain-relieving drugs. Since the discovery that aspirin and similar drugs work by inhibiting the synthesis of prostaglandins. The most common side-effects of ibuprofen are gastrointestinal: nausea, stomach pain and cramping in addition to fatal liver damage with overdose. Ibuprofen was the first of several new drugs that are now collectively referred to as "non-steroidal anti-inflammatory drugs" (NSIDs)
    3. More products of this nature can be expected in the future
  • ALMOST EVERYONE SUFFERS FROM A COLD SOME TIME
    1. A common cold is caused by any one of many viruses - two groups of viruses are known to be associated with colds: the rhinoviruses and the coronaviruses
    2. These viruses zero in on the upper respiratory tract, at first causing irritation that can lead to reflex coughing and sneezing. Increased irritation inflames tissue and is followed by soreness and swelling of the mucous membranes - as a defense mechanism, the mucous membranes releases fluid that causes post-nasal drip that irritates the throat
    3. Colds are not completely preventable, but there are four things you need to know to help you avoid the cold virus: 1) up to 100 times as many virus particles are produced and shed from the nasal mucosa as from the throat, 2) there are few virus particles in saliva, Viruses survive on dry skin and non-porous surfaces for about 3 hours, and 4) most cold viruses enter the body through the nostrils and eyes (via the hands). Therefore wash your hands frequently
    4. Interferon has been used with good results in the prevention of cold symptoms
    5. Choosing the correct OTC drug may mean reading the labels and doing comparison shopping. There are three common types of ingredients in modern cold remedies: antihistamines (for a runny nose and sneezing), nasal decongestants (for relief of swollen membranes in the nasal passages - sympathomimetics), and analgesic-antipyretics
    6. NOTE: Table 14.2 in your book - DECONGESTANTS should be above (Sympathomimetic)