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Dextromethorphan

Dextromethorphan


What Kind of Drug Is It?

Dextromethorphan (DXM) is an ingredient in more than 100 over-the-counter (OTC) cold, flu, and cough remedies. It is used specifically to suppress coughs. The drug is widely used in OTC medications because, at normal dosages, it does not produce side effects in most people. Dextromethorphan is a synthetic drug, meaning that it is manufactured in a laboratory.

The chemical is derived from levomethorphan—a synthetic substance that mimics the behavior of opiates such as heroin, morphine, or codeine. In its pure form, levomethorphan shows many similarities to the opiates, including the potential for addiction. Separated from the levomethorphan, dextromethorphan loses its painkilling component and is also thought to be non-addicting.

Higher Doses and Dangerous Combinations

Because so many easily purchased products contain dextromethorphan, it can be obtained legally for abuse in higher doses. It is not a controlled substance, and no one needs a prescription to purchase it. Nevertheless, emergency doctors, pharmacists, and law enforcement officials are aware of the problems that the drug can cause when abused. They warn of the drug's potential for producing a whole host of dangerous effects on the brain and central nervous system when taken in high doses or in combination with other drugs or alcohol.

Dextromethorphan has been described as a "dissociative anesthetic." This means that it is a substance that alters perception. As one young user told People Weekly magazine in 2004, "You start feeling numb. And finally, you're gone. You're out of your body. You're not there anymore." This is a basic description of "dissociative" feelings.

Official Drug Name: d-3-methoxy-N-methylmorphinan (commonly called dextromethorphan, pronounced dekstroh-meth-ORR-fan); sometimes referred to by shortened name DXM

Also Known As: DM, DXM, dex, drex, red devils, robo, robo-tripping, skittles, triple-C, tussin, velvet, vitamin D

Drug Classifications: The U.S. Department of Justice, Drug Enforcement Administration Diversion Control Program does not list dextromethorphan as a controlled substance; it has no Schedule listing

The drug is also well known for producing: 1) hallucinations—visions or other perceptions of things that are not really present; and 2) an inability to walk or communicate. In worse case scenarios, the drug has caused psychotic behavior.


Robert Finn compared the use of dextromethorphan to the use of the hallucinogenic drug PCP (phencyclidine) in a 2004 article for Family Practice News. Finn wrote: "While some symptoms of DXM intoxication are similar to those of PCP intoxication, there's one important difference: People on PCP are able to walk and they're able to become violent. On the other hand, people on DXM become immobilized." (An entry on PCP [phencyclidine] is also available in this encyclopedia.)

One of the greatest dangers of dextromethorphan use is that it is commonly sold in combination with other medications. These include: 1) acetaminophen (pronounced uh-SEE-tuh-MINN-uh fenn), a non-aspirin pain reliever, such as Tylenol; 2) antihistamines, drugs that block histamine, a chemical that causes nasal congestion related to allergies; and 3) guaifenesin (pronounced gwy-FENN-ess-inn) or other expectorants. Multisymptom cold and cough medications are formulated for correct use by the proper dosage. The use of larger doses not only delivers high quantities of dextromethorphan, it can also deliver large doses of the other ingredients. This can lead to nausea, anxiety, and organ damage.

Abusers of dextromethorphan try to find it in preparations that do not contain these other ingredients, sometimes even purchasing it in powdered form from Internet sites. In this case, problems arise with doses. Unlike many abused drugs, which act predictably as dosage increases, dextromethorphan worksasa "plateau" drug. High doses cause a different set of reactions in the brain than lowdoses. Thus, a mismanageduse of dextromethorphan can cause an inexperienced abuser to undergo a bewildering hallucination-filled trip, possibly ending in a seizure or a coma.

Dangerous in High Doses


Medications available in the local drug store can be very dangerous, even deadly, when taken in high doses or combined with other drugs. Over-the-counter medications sometimes combine dextromethorphan with other ingredients meant to ease the multiple symptoms of colds and flu. Some of these other ingredients, and their potential as poisons, include:

  • Acetaminophen (uh-SEE-tuh-MINN-uh-fenn), a pain reliever such as Tylenol. In high doses, this substance causes severe damage to the liver and other internal organs. It can lead to death.
  • Guaifenesin (gwy-FENN-ess-inn), a mucusthinner and expectorant. In high doses, it causes nausea and vomiting.
  • Pseudoephedrine hydrochloride (SUE-doh-ih-FEH-drinn high-droh-KLOR-ide), a decongestant. Overdoses of this medication can lead to nervousness, insomnia, heart palpitations, and breathing problems.
  • Chlorpheniramine maleate (KLOR-fenn-earuh-mene MAL-ee-ate), an antihistamine such as Chlor-Trimeton. This drug is broken down by the same liver enzyme as dextromethorphan. Overdoses of the two drugs taken together can be fatal.

Overview

In 1949, American chemists applied for a patent on dextromethorphan, after having isolated it from its parent drug, levomethorphan, a synthetic opioid. During the 1950s, abuse of cough syrups containing codeine was a serious problem for adults and teenagers. This led manufacturers of cough and cold remedies to search for a product that would suppress coughs without causing drowsiness or promoting addiction. Dextromethorphan seemed to be the answer. By 1959, it had won approval by the U.S. Food and Drug Administration (FDA) for use as a cough remedy. In the 1960s, a dextromethorphan-only pill, Romilar, was introduced as an over-the-counter medication. However, it was pulled from the market when its potential for abuse became known.

The World Health Organization (WHO) classified dextromethorphan as a non-analgesic, non-addictive substance in the late 1960s. (An analgesic is a drug that relieves pain.) Yet, pharmaceutical companies decided to use the drug in combination form with other agents. The era of multi-symptom cough, cold, and flu remedies was born, with a variety of products for adults and children.


So Easy to Get

Modern pharmacies, grocery stores, and even convenience stores stock cough remedies with dextromethorphan. The drug can be found in brand-name products such as Coricidin, Robitussin, Vicks NyQuil, Dimetapp DM, Alka-Seltzer Plus Cold and Cough, Sudafed cough products, Tylenol cold products, and Vicks Formula 44. The street names "triple-C" and "skittles" have been coined to describe Coricidin. "Robo-tripping" is slang for abuse of liquid cough syrups such as Robitussin.

According to the Cleveland Plain Dealer, reported cases of teen dextromethorphan abuse more than doubled nationwide between 2000 and 2003. An increase of dextromethorphan abuse among teenagers sparked parent groups, legislators, and pharmacies to take action. Drug Topics magazine noted that some national chain pharmacies, such as CVS and Wal-Mart, have programmed their computer scanners to ask for an age identification before selling DXM products. Others, including Walgreens, restrict the number of packages a customer can buy. Some drugstores have even moved these medications from the main aisles into the pharmacy area, so the sale of these drugs can be monitored. By September of 2004, several states were considering legislation that would prohibit anyone under the age of eighteen from buying products containing dextromethorphan.

The easy availability of dextromethorphan sometimes makes it the first choice for abuse among teens who might feel uncomfortable buying illegal drugs. However, in high doses it is as dangerous and unpredictable in its effects as PCP and ketamine. (An entry on ketamine is also available in this encyclopedia.)

In the Palm Beach Post, Carolyn Susman detailed the "laundry list" of side effects from dextromethorphan abuse, including "dissociation … confusion, dizziness, double or blurred vision, slurred speech, impaired physical coordination, abdominal pain, nausea and vomiting, rapid heart beat, drowsiness, numbness of fingers and toes, and disorientation." This list does not include the even more dangerous symptoms associated with use of dextromethorphan in combination with other drugs.

What Is It Made Of?

Dextromethorphan is a synthetic substance, meaning it is manufactured in a lab. It was first developed by modifying levomethorphan, a non-carbon-containing opioid. While the brain "reads" levomethorphan like an opiate, it does not "read" dextromethorphan the same way. Thus, at recommended doses, dextromethorphan does not cause drowsiness, dizziness, or sedation.

Some people—about seven in every one hundred—have a genetic trait called CYP2D6 deficiency. This is the lack of a liver enzyme that works to break down dextromethorphan. For these people, even the recommended dose of products containing dextromethorphan can produce unpleasant feelings of anxiety, restlessness, or "jitters." Anyone with the CYP2D6 deficiency who abuses dextromethorphan can experience a psychotic episode, or a period of intense fear, paranoia, and powerlessness. People with this enzyme deficiency also face a greater risk of fatal poisoning by dextromethorphan.

How Is It Taken?

Products containing dextromethorphan include pills, cough syrups, and liquid cold and flu medications. Dextromethorphan is not snorted through the nostrils or injected, even in its pure powdered form. Over-the-counter cold and flu remedies list all active and inactive ingredients as well as specific dosage charts. Physicians and pharmacists recommend that patients taking liquid medications use precise measuring cups, often provided with the products, rather than teaspoons or tablespoons from a kitchen drawer. If the product does not come with a measuring cup, pharmacies have them in stock and will provide one upon request.


Are There Any Medical Reasons for Taking This Substance?

Dextromethorphan is recommended for quieting coughs. It does not work on the nose or the throat, but rather on the brain and the central nervous system, to lessen the body's chemical signals to cough.

According to a 1997 report in the journal Pediatrics, dextromethorphan may not be safe for use in children even though it can be found in pediatric products. First, parents may administer too much medicine to a child, leading to negative side effects. Second, very young children also have immature livers that cannot properly metabolize dextromethorphan and other cold remedies.

Most important, for children and adults, coughs serve a practical purpose. They clear the airways of fluids, allowing for better breathing. Some illnesses, including asthma, cystic fibrosis, allergies, and pneumonia, can actually be made worse by the use of dextromethorphan. The drug is only recommended for brief episodes of coughing, such as those accompanying colds and flu. Patients with chronic, or long-term coughing, should be seen by a doctor.

Usage Trends

Between 2000 and 2003, the number of dextromethorphan abuse cases reported to national poison control centers more than doubled, from 1,623 to 3,271, according to the Cleveland Plain Dealer. The vast majority of dextromethorphan abusers are teenagers or young adults. The main way they get the drug is by buying it in over-the-counter medications.

Deaths from Over-the-Counter Drugs?

Since 2000, newspapers and magazines have reported numerous deaths associated with dextromethorphan abuse. A twenty-year-old Colorado man was found dead in his bed of a Coricidin HBP overdose in May of 2004, as reported in the Rocky Mountain News. A few months earlier, People Weekly magazine detailed the similar death of a twenty-two-year-old college honor student who overdosed on powder he bought on the Internet. The same People Weekly article mentioned a fourteen-year-old Colorado boy who was killed by an automobile when trying to cross a busy highway to purchase more pills.

Two mothers who found their teenagers abusing dextromethorphan have started a parents' awareness group in Oregon. One of those mothers told the Eugene, Oregon Register-Guard: "What parents should do if their child is on these pills, they need to take them to the doctor or the hospital because of the damage that can be done. Definitely get medical help."

In a scientific study published in the journal Adolescence, Momodou N. Darboe suggested that cough syrup provides "an attractive choice for experimental abuse or misuse." Darboe found several reasons for the abuse of over-the-counter cough syrups. First, of course, is availability, then affordability. Teens with limited spending money—and perhaps a fear of breaking the law—can purchase cough syrups with dextromethorphan.

The second reason for cough syrup abuse, according to Darboe, is the "fear factor." The author explained: "Taking three or more pills of anything bears the threat … of suicide. Powders or needles, if not prescribed, are often associated with harder, more addictive, illicit, and dangerous drugs and substances. Since cough syrup, on the other hand, [does not have] these qualities or connotations, it is relatively easier for a curious teenager to [want] to experiment with it."

Darboe made another observation in the Adolescence report. According to the author, "other studies show abuse of licit [legal] drugs to be a precursor of illicit drug use." Put simply, a person who takes chances abusing dextromethorphan, an easily obtainable drug, may be more likely to begin taking illegal and more addictive drugs.

Effects on the Body

Taken in its recommended doses, dextromethorphan sends a chemical signal to the brain to quiet a persistent cough. The medicine's effects begin about fifteen to thirty minutes after taking it, and they last between three and six hours. Most doctors do not recommend using over-the-counter cold medications for more than a week. Cold symptoms that last longer than a week might be the first signs of a more serious illness and a doctor should be consulted. At its normal dosage level, dextromethorphan does not cause any side effects, and it is not habit-forming.

Signs of DXM Abuse


To help people know if someone they care about is abusing DXM, health professionals note the following warning signs:

  • Stockpiles of cold and cough medications, more than anyone would need for a bout of the flu.
  • Empty pill packets or bottles of cough syrup found in odd places, such as under beds, in dresser drawers, or in wooded areas near homes or schools.
  • The presence of strange-looking tablets in various shapes and colors, evidence of purchase from the Internet.
  • Bookmarked Web sites or emails that encourage DXM use.

Various Web sites, such as Kids Health for Parents (http://kidshealth.org/parent/), provide information on DXM and other drug abuse warning signs.

What Are the Plateaus for Dextromethorphan Overdose?

As an abused drug, dextromethorphan has been compared to hallucinogens such as ketamine and PCP. Four "plateaus" have been identified for dextromethorphan overdose. Each plateau carries a different set of symptoms and behaviors. The higher the plateau of abuse, the greater the chances of permanent brain damage, psychological addiction, or lasting behavioral problems in the user.

At the first plateau, users report mild sensations of dizziness or euphoria.They might perceive music as either more pleasant or as strangely distorted. A first-plateau dextromethorphan abuser can still move and carry on conversations, but perceptions are altered to the point where driving a car or making other value judgments might be very difficult.

At the second plateau, users begin to experience visual hallucinations—colors swirling through the vision field with eyes closed. At this level, users also experience nausea, often with vomiting, and they have more trouble walking and communicating. To an outside observer, second plateau dextromethorphan abusers are clearly "on something." They behave as if drunk or stoned. Double vision can also occur.

Upon reaching the third plateau, users experience a wider variety of hallucinations. All sensory input is altered to some degree. An abuser might see visions that are not there or misunderstand what he or she is actually seeing. Walking and talking become very difficult, and the user becomes disoriented and out of touch with reality. This can lead to bouts of paranoia (a feeling of great personal danger) or to the recall of forgotten memories, both pleasant and unpleasant. Because motor skills become seriously impaired at this level, abusers can be a danger to themselves just from tripping and falling. Judgment is altered, leading to the possibility of self-destructive behavior.

DXM Plateaus


The symptoms of dextromethorphan abuse are categorized according to the strength of the dosage taken by the user. These categories are called plateaus. According to the article "What Every Parent Needs to Know about Cough Medicine Abuse," available on the Drug Free AZ Web site, common symptoms of abuse at the various plateaus include:

  • First plateau: mild euphoria, mild dizziness, mild distortions of color or sound.
  • Second plateau: visual hallucinations, blurred vision, slurred speech, drowsiness, nausea, and vomiting.
  • Third plateau: double vision, disorientation, hallucinations, rapid movements of the eyes, paranoia, difficulty speaking and walking.
  • Fourth plateau: "out of body" experiences, complete loss of motor control, altered sense of time and altered sense of reality, hallucinations involving vision, hearing, and touch.

Users undergoing withdrawal from dextromethorphan may have difficulty sleeping and suffer from depression or feelings of hopelessness.

The fourth plateau experience is extremely dangerous and sometimes deadly. At this level, the dissociation, or split between mind and body, occurs. Bizarre thoughts and hallucinations abound. Meanwhile, the abuser has little or no motor control and simply cannot move. An immobilized user may choke on his or her vomit and suffocate, or suffer seizures and brain damage. Those who abuse dextromethorphan at these highest dosages are at the greatest risk of sudden death. Survivors of fourth plateau use may become psychologically addicted to dextromethorphan and continue abusing it in search of more hallucinations and that "out of body" feeling.

Reactions with Other Drugs or Substances

As previously stated, over-the-counter multi-symptom cold and cough products contain several ingredients that can be poisonous at high doses. The dextromethorphan abuser may unknowingly risk fatal organ damage by taking too much acetaminophen. Breathing problems can occur if too much decongestant is consumed with DXM. Combining dextromethorphan with prescription drugs, controlled substances, or alcohol can prove fatal.

Even at normal doses, dextromethorphan can react negatively with prescription sedatives, antidepressant drugs known as MAO inhibitors, and the antidepressant family of drugs that includes Desyrel (trazadone) or Serzone (nefazodone). Any amount of dextromethorphan combined with a selective serotonin reuptake inhibitor (SSRI), such as Prozac, Paxil, or Zoloft, can cause chemical imbalances in the brain. Dextromethorphan is also to be avoided by anyone taking tricyclic antidepressants or medication for bipolar disorder, such as lithium carbonate or Depacote. (A separate entry on antidepressants is available in this encyclopedia.)

Occasionally, drug dealers will pass dextromethorphan pills or powders off as ketamine, ecstasy (MDMA), or even heroin. (An entry on each of these drugs is available in this encyclopedia.) Unsuspecting users can suddenly find themselves with a whole series of symptoms for which they are not prepared. In the New York Times, Jacob Sullum reported that this substitution of dextromethorphan for other illicit drugs has led some dance clubs to test pills and powders on-site in order to protect customers from unknowingly taking overdoses of the dangerous DXM.

The combination of dextromethorphan products and alcohol can cause extreme nausea and vomiting, as well as a greater loss of motor control.

Treatment for Habitual Users

The FDA does not consider dextromethorphan an addictive substance. However, press coverage of dextromethorphan abuse has uncovered cases of psychological dependence, or an addiction created by an emotional need for the substance. A young user told Teen People magazine in 2003: "I thought I could just use Coricidin for fun, that it didn't matter. I never expected to get hooked." This user reported months of daily abuse that led to physical problems, including blood in her urine and a complete loss of interest in school and friendships. "I'll never be able to get that time back," she said. "If I could erase it and make it go away, I would."


The antidote drugs that work on opiate overdoses, such as naloxone (Narcan), do not ease the symptoms of dextromethorphan overdose. According to the American Journal of Emergency Medicine, the emergency medical response to dextromethorphan overdose is to administer oral medications to induce vomiting and use intravenous fluids to combat dehydration. Usually the abuser simply has to ride out the symptoms under observation at a hospital.

Those abusers motivated to end their use of dextromethorphan will find no physical symptoms of withdrawal. However, the psychological pull of the drug may be difficult to overcome. Serious abusers may have to spend time at inpatient rehab facilities, fighting depression, insomnia, and feelings of worthlessness. Counseling with a licensed addiction therapist or psychiatrist will help the recovering abuser to identify the underlying reasons for attraction to the drug. Additionally, dextromethorphan abusers are welcome in twelve-step programs such as Narcotics Anonymous, where they can meet other recovering substance abusers and find twenty-four-hour support through meetings and telephone hotlines.

Consequences

Long-term abuse of over-the-counter products containing dextromethorphan can lead to organ damage, brain damage, and permanent damage to the central nervous system. Deaths have been reported from dextromethorphan alone, as well as in situations where the user combined dextromethorphan with alcohol, sedatives, or controlled substances. The changes in judgment that come with dextromethorphan abuse can lead to accidental injuries, automobile crashes, and "date rape" situations.

The Law

Dextromethorphan is not a controlled substance. It can be purchased legally in pharmacies, grocery stores, and convenience stores. Some national pharmacy chains have opted to sell cough and cold products only to those over the age of eighteen, or in small quantities. The ability to purchase products containing dextromethorphan varies from store to store. Powdered dextromethorphan is sold on some Internet sites. However, the quality of the product, even its chemical composition, is not regulated. The Internet auction site eBay voluntarily decided not to allow listings of DXM for sale.

Intoxication

Police officers have pulled over drivers under suspicion of drunk driving, only to find that the drivers were under the influence of dextromethorphan. In those cases, the drivers have been prosecuted under the same statutes that apply to drunk driving. "Driving While Intoxicated" and "Driving under the Influence" do not apply strictly to alcohol, but rather include substances such as dextromethorphan.

In a report on the Greater Dallas Council on Alcohol & Drug Abuse Web site, the legal aspects of DXM abuse were discussed. "Even though [DXM] is not regulated as a prescription drug, or as a controlled substance, being intoxicated on ANY drug in a public place can subject a user to prosecution for disorderly conduct, disturbing the peace, and similar violations."


Furthermore, anyone who distributes nonprescription doses of an over-the-counter drug to a minor can face prosecution under laws that protect children.

Some pharmacies have reported thefts of cold and cough products. Anyone caught trying to steal dextromethorphan products from a store can be prosecuted for shoplifting.

In 2003, the states of Texas and North Dakota refused to pass legislation that would make the purchase of certain cold products illegal for persons under the age of eighteen. A similar measure was struck down in California in 2004. As of 2005, legislation was pending in New Jersey. The state of New York passed a bill creating misdemeanor charges for anyone who gives a minor two or more products containing dextromethorphan. The mindset of most state legislators seems to be that the benefits of proper use of over-the-counter cold and cough remedies outweigh the dangers of dextromethorphan abuse.

The tide of opinion could change, however. In a worst case scenario, a widespread epidemic of dextromethorphan abuse may lead the Drug Enforcement Administration (DEA) to add the drug to its list of controlled substances. Then the products containing dextromethorphan would require a prescription from a licensed doctor. In the meantime, the burden for preventing dextromethorphan abuse falls on parents and concerned friends who detect changes in behavior, motivation, and overall health in their loved ones.

For More Information

Books

Clayman, Charles B., editor. The American Medical Association Encyclopedia of Medicine. New York: Random House, 1989.

Physicians' Desk Reference, 55th ed. Montvale, NJ: Medical Economics Company, 2001, rev. 2005.

Periodicals

Bane, Jason. "The Scariest Drug Epidemic You've Never Heard Of: The Latest Craze for Teens Looking to Get High Doesn't Involve Illegal Drugs." Teen People (December 1, 2003): p. 136.

Bishop, Bill. "Teen Abuse of Cold Pills on the Rise." Register-Guard (February 23, 2003): p. A1.

Blum, Agnes. "Cough Syrup Abuse on Rise, Internet Sites Exacerbate Problem." Capital (January 6, 2000): p. C1.

"Cold Medicine High." State Legislatures (September, 2004): p. 11.

Darboe, Momodou N. "Abuse of Dextromethorphan-based Cough Syrup as a Substitute for Licit and Illicit Drugs: A Theoretical Framework." Adolescence (spring, 1996): p. 239.

Dignam, John. "Police Warn of Cough Syrup Abuse." Worcester Telegram & Gazette (December 3, 2003): p. B1.

Fields-Meyer, Thomas, and Melinda Janiszewski. "Over the Counter Killer: It's Cheap, It's Legal, and It's Available at Any Drugstore. DXM, a Cough Medicine Ingredient, Is the Latest Craze for Teens Who Want to Get High—or Die Trying." People Weekly (February 2, 2004): p. 48.

Finn, Robert. "Dextromethorphan Presents Increasing Abuse Problems." Family Practice News (October 1, 2004): p. 39.

Horton, John. "Kids Find They Can Start High at a Store." Plain Dealer (September 27, 2004): p. B1.

Levy, Sandra. "R.Ph.s Keeping Eyes Peeled for Dextromethorphan Buyers." Drug Topics (May 17, 2004): p. 44.

Scanlon, Bill. "Cough Syrup Abuse Rises: Center Notes 20 Percent Increase in '03, Reports One Death in '04." Rocky Mountain News (June 21, 2004): p. A4.

Sloat, Bill. "Teens Abusing Cold Pills, Officials Warn Parents." Plain Dealer (February 19, 2000): p. B1.

Strickland, Leif B. "Drug Fad Catching Parents, Professionals by Surprise: Teens Abusing Cough Medicine Ingredient." Dallas Morning News (July 15, 1999): p. A1.

Sullum, Jacob. "When Holding a Party Is a Crime." New York Times (May 30, 2003): p. A27.

Susman, Carolyn. "Doctors Worried about Cough-Syrup Abuse." Palm Beach Post (December 15, 2004): p. E3.

"Use of Codeine- and Dextromethorphan-Containing Cough Remedies in Children." Pediatrics (June, 1997): p. 918.

Wolfe, Timothy R., and E. Martin Caravati. "Massive Dextromethorphan Ingestion and Abuse." American Journal of Emergency Medicine (Volume 13, 1995): pp. 174-176.

Web Sites

"Cough and Cold Medicine Abuse." Kids Health for Parents.http://kidshealth.org/parent/ (accessed June 30, 2005).

"Dextromethorphan." U.S. Department of Justice, Drug Enforcement Administration: Diversion Control Program.http://www.deadiversion.usdoj.gov/drugs_concern/ (accessed June 30, 2005).

"DXM (Dextromethorphan)." Greater Dallas Council on Alcohol & Drug Abuse.http://www.gdcada.org/statistics/dxm/ (accessed June 30, 2005).

Wall, Andrea L. "Abuse of OTC Drugs in Adolescence." Nonprescription Medicines Academy.http://www.nmafaculty.org/ (accessed June 30, 2005).

"What Every Parent Needs to Know about Cough Medicine Abuse." Drug Free AZ.http://www.drugfreeaz.com/ (accessed June 30, 2005).

See also: Over-the-Counter Drugs

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