Dextromethorphan has been in use for a long time as a medication to ease distressful cough. It is sold over-the-counter as a single formulation in tablets, capsules, gel caps and syrups under various brand names. It also appears in several combination cough and cold medications with antihistamines and acetaminophen.
Recent incidences of abuse with fatalities among youth have brought some notoriety to this previously relatively unknown drug. Its availability for sale on the Internet as "DXM" has further added to its infamy, with actual debates in certain states to move it into the class of prescription drugs and even classify it as a narcotic.
Chemistry
Dextromethorphan is a synthetic organic compound that looks like codeine in certain ways but unlike codeine, is not an opioid analgesic. It occurs in its free state as a white crystalline or powdery substance with limited solubility in water or alcohol.
Actions
Dextromethorphan binds to non-opioid receptors in the area that regulates the respiratory system and suppresses the cough impulse. This is the antitussive effect that is exploited in its use in cough medications.
Dextromethorphan also increases the availability of an endogenous substance in the brain called serotonin. It achieves this by blocking the re-uptake mechanisms that shortens the effects of this substance. This results in euphoria, hallucinations and excitability. This is usually achieved at very high doses (about ten times the usual doses for cough suppression). This property of Dextromethorphan has made it notorious in recent times as a drug of abuse, especially among teenagers.
Uses and Formulations
Dextromethorphan is approved for use as a cough suppressant, appearing as the sole active ingredient, usually as Dextromethorphan hydrobromide, or in combination with other drugs like antihistamines and analgesics in cold remedies. It is found in tablets, suspensions, gel caps and capsules to be taken orally. There has been recent news of inhalation of the free powder but this is in the context of abuse.
The usual dose in children over six years is 10 to 15 milligrams three to four times a day. In adults, it is used up to 30 milligrams, four times a day. It is to be avoided in people with certain chronic respiratory illnesses like bronchitis and emphysema where the cough impulse is to be encouraged to clear secretions. It is also to be avoided in people with atopic dermatitis.
Adverse Reactions
Infrequently reported side effects are dizziness, drowsiness, nausea, vomiting and abdominal pains. At much higher doses, restlessness, agitation and even psychosis has been reported. It is not to be taken with other depressants of the nervous system like alcohol and sleep medication as this could spell disaster with the potential of shutting down the respiratory system. People on antidepressant therapy, particularly those on serotonin reuptake inhibitors like Paroxetine or those on monoamine oxidase inhibitors should avoid Dextromethorphan. If in doubt as to your other medications, consult a doctor before using this medication.
Abuse and Toxicity
At extremely high doses, often exceeded in teenage drug abuse, it can cause excitability, hallucinations, respiratory depression and death. It is the visual hallucinations and euphoria of excitability that the adolescents, who abuse this drug, seek. This high is called dexing or robo tripping. The altered consciousness seen with Dextromethorphan is comparable to that produced by PCP. Because it is used in combination with other drugs in formulations, there is often mixed toxicity in those who abuse this drug.
The availability of the free form of this drug on the Internet, originally meant for research, but now available to all buyers, has put this drug in the limelight in recent times as a drug of abuse. In the usual formulations, it will take several bottles of cough syrup to achieve the blood levels that produce the desired high. However, in the free form, inhalation is possible and higher concentrations in the blood are more readily attained. It is certainly a drug to be 'kept out of the reach of children'.
