In the early 1950's, researchers were searching for a non-addictive cough suppressant to replace codeine
and dextromethorphan was identified as a prime candidate for this application. Dextromethorphan or DXM became available by prescription in 1954 and in 1958 DXM became an over-the-counter drug.
DXM was available over-the-counter in tablet form under the brand name Romilar during the 1960's and 1970's. However, in 1973 Romilar was removed from the shelves after a sudden rise in recreational use of the pills. Cough syrup was developed as a deterrent to ingesting the drug recreationally. In the 1980's, gel capsule forms of the drug cropped up in the form of Robitussin CoughGels as well as other generic versions.
When taken appropriately, DXM is an antitussive medicine. When DXM is taken for its recreational effect, usually in doses that highly surpass the therapeutic index, the substance is classified as a dissociative hallucinogenic drug and a NMDA receptor antagonist.
DXM is primarily used as a cough suppressant to treat the cough symptoms of the flu or the common cold. DXM is also commonly taken recreationally and this use is known as "robo-tripping" after the well-known brand name Robotussin. To combat this use many drug stores in the US have moved DXM products behind the counter so that one must be of age to purchase them.
DXM has cough suppressant effects in its recommended dose range. There are two forms of DXM sold, dextromethorphan hydrobromide and dextromethorphan polistirex. Polistirex's duration of effects are considerably longer than hydrobromide because of an ion exchange that is required before its dissolution into the blood.
When taken recreationally, DXM effects are often described in plateaus by its users. The first plateau is at dosages of 1.5 to 2.5 mg/kg and its effects are described as euphoria, intensification of emotions, and loss of balance. At the second plateau which is 2.5 to 7.5mg/kg the effects are similar to first but slightly more intense and closed-eye hallucinations are possible. When entering the third plateau at 7.5 to 15.0 the effects increase dramatically and may include an inability to comprehend language, abstract hallucinations, and decision making impairment. The fifth plateau is at 15.0 mg/kg or more and an individual may experience a loss of control of his or her own body, out-of-body experiences and delusions.
Dextromethorphan use can produce numerous side effects including fatigue, apathy, nausea, vomiting, urinary retention, constipation, insomnia, nightmares, impaired memory and decreased libido.
Drugs similar to DXM include ketamine
and phencyclidine (PCP
). All three of these drugs are NMDA receptor antagonists. DXM may even create a false positive for PCP.
DXM has the potential to be habit forming and can produce a psychological dependence. However, it does not produce a physical addiction.
DXM withdrawal usually consists of depression
, cognitive difficulties and a desire to relapse.
Overdose from DXM itself is possible but many of the overdose situations are from the other active ingredients included in cough suppressant preparations. Overdose from DXM itself can cause breathing problems, blurred vision, coma, convulsions, muscle spasticity and vomiting.