Overload

DXM

Category: Medicines

Type

Involuntary and voluntary

Introduction and description

 

Dextromethorphan (DXM or DM) is an antitussive (cough suppressant) drug. It is one of the active ingredients in many over-the-counter cold and cough medicines, such as Robitussin, NyQuil, Dimetapp, Vicks, Coricidin, Tussin, Delsym, and others, including generic labels.

Dextromethorphan has also been used in other ways by doctors, ranging from pain relief to ‘psychological applications’.  It has some rather difficult to understand uses:
a combination of dextromethorphan and quinidine by has been shown to alleviate symptoms of easy laughing and crying (sic) in patients with multiple sclerosis”.

It is sold in syrup, tablet, spray, and lozenge forms. In its pure form, dextromethorphan occurs as a white powder.

DXM is also used in considerable amounts by the so-called ‘recreational drug user’.   It can be obtained over the counter without a prescription, it is relatively inexpensive, a cough is easily faked if you want your Mum to buy it for you and it is legal.  These children – because children they often are - have discovered that if you exceed the label-specified maximum dose, it acts as a ‘dissociative hallucinogen’, or to put this another way you can get hallucinations, visions and out of body experiences from it, or in some cases near death and occasionally actual death experiences, another sort of experience, but spiritual none the less.

Background

History

 

Dextromethorphan was invented during US Navy and CIA-funded research that sought a "nonaddictive substitute for codeine". 

It was first patented in 1954. The U.S. Food and Drug Administration (FDA) approved dextromethorphan for over-the-counter sale as a cough suppressant in 1958.

It was used to replace codeine phosphate, the most widely used cough medication at the time, which was found to be addictive.

During the 1960s and 1970s, dextromethorphan became available in an over-the-counter tablet form by the brand name Romilar. In 1973, Romilar was “taken off the shelves after an unexpected burst in sales caused by frequent abuse”.  The pharmaceutical companies replaced the tablets with syrup and presumably stopped monitoring the sales.

Mechanism of action

 

No one really knows how it works. “ Its mechanism of action is via multiple effects, suggestions include as a nonselective serotonin reuptake inhibitor, a sigma-1 receptor agonist and as an NMDA receptor antagonist".  But one of the rather more interesting comments is that “it produces effects similar to those of the controlled substances ketamine and phencyclidine (PCP)”.

Dextromethorphan is the dextrorotatory enantiomer of the methyl ether of levorphanol, an opioid analgesic. It is also a stereoisomer of levomethorphan, an opioid analgesic.  So perhaps the more obvious way it works is staring us in the face - the new laudanum.

Allergic reactions

DXM can trigger histamine release - an allergic reaction – which is why it is sometimes sold, still over the counter, with anti-histamines added.

DXM only products as of February 2011

Benylin Dry Coughs Original / Non-Drowsy -  Johnson & Johnson (United Kingdom)

Active Ingredients (per teaspoonful/5mL): DXM HBr 7.5 mg.
CVS Tussin Maximum Strength Cough Formula
Active Ingredients: (per teaspoonful/5mL):  DXM HBr 15 mg, Alcohol 1.4%
VS Tussin Cough Liquid Gels
Active Ingredients: (per liquid gel): DXM HBr 15 mg.
PediaCare Children's Long-Acting Cough Liquid by McNeil-PPC
Active Ingredients (per teaspoonful/5mL):  DXM HBr 7.5 mg.
Robitussin CoughGels Long-Acting -  Wyeth Consumer Healthcare
Active Ingredients (per softgel):  DXM HBr 15 mg.
Robitussin Cough Long-Acting Liquid -  Wyeth Consumer Healthcare
Active Ingredients (per tsp/5ml):  DXM HBr 15 mg,
Sucrets 8-Hour Cough Relief DM Cough Formula Lozenges -  Insight Pharmaceuticals
Active Ingredients (per lozenge):  DXM HBr 10 mg.
Triaminic Long-Acting Cough Liquid -  Novartis Consumer Health
Active Ingredients (per teaspoonful/5mL):  DXM HBr 7.5 mg.
Triaminic Thin-Strips Long-Acting Cough -  Novartis Consumer Health
Active Ingredients (per strip):  DXM 5.5 mg (equivalent to DXM HBr 7.5 mg).
Vicks Formula 44 Maximum Strength Cough Relief -  Procter & Gamble
Active Ingredients (per tablespoon/15ml):  DXM HBr 30 mg.
Vicks Dayquil Cough -  Procter & Gamble
Active Ingredients (per tablespoonful/15mL):  DXM HBr 15 mg.
Zicam Cough Relief  -  Matrixx Initiatives
Active Ingredients (per spray): DXM HBr 5 mg
Zicam Cough Max and Zicam Cough Max Nighttime  -  Matrixx Initiatives
Active Ingredients (per spray):  DXM HBr 6 mg
Zicam Cough Max Melts and Zicam Cough Max Nighttime  -  Matrixx Initiatives
Active Ingredients (per tablet):  DXM HBr 30 mg

Other products

 

Many DXM-containing products also contain other active ingredients which can be dangerous or fatal in high doses, for example:

  • Acetaminophen  - paracetemol
  • Aspirin
  • Chlorpheniramine Maleate
  • Guaifenesin - can cause vomiting, nausea, and headache at too high a dose
  • Phenylephrine (Hydrochloride)
  • Pseudoephedrine (Hydrochloride)
  • Sorbitol

All the above in high doses can cause very severe effects, but high doses of Chlorpheniramine Maleate in particular (CPM) can cause extremely severe and life-threatening symptoms including seizures; shortness of breath or troubled breathing; weakness; loss of consciousness; severe dryness of mouth, nose, or throat; bleeding from skin, mouth, eyes, rectum, and vagina; and possibly death.

Side-effects

Side-effects of dextromethorphan are actually typical of an opioid, are of course dose dependent and include:

Sudden infant death  

body rash/itching

nausea

drowsiness

dizziness

hallucinations

disassociation

vomiting

blurred vision

dilated pupils

sweating

fever

bruxia

hypertension

shallow respiration

diarrhoea

urinary retention

Visions

Difficulty breathing

 “In some documented cases, dextromethorphan has produced psychological dependence”.

Effects depend on various 'plateaus' which depend on how much a person has over dosed.  As William White describes it  “The first is of losing one's body, or having one's heart stop beating. This can be very disturbing if a naive user interprets it as heart failure! The second transitional effect is a temporary loss of all sensory input (this does not always occur), as if one were in a sensory deprivation tank. This is often accompanied by severe Lilliputian hallucinations…. One person reported feeling as if he shrunk down to the size of a proton, and the rest of the world were light-years away”.

Mood can range from absolute mania to panic. Panic attacks have occurred at the so called 'third plateau'.

How it works

Healing - It is I think important to realise that DXM does not cure a cough.  Following oral administration, dextromethorphan is rapidly absorbed from the gastrointestinal tract, where it enters the bloodstream and crosses the blood-brain barrier.  In effect it acts centrally - meaning that it acts on the brain -  as opposed to locally – meaning on the respiratory tract. It elevates the threshold for coughing.  So the lungs will effectively get more congested with mucus and the germs the body is trying to expel via the coughing, giving the immune system more of a challenge.  We cough as a protective action, however wearing it can be.  As long as we spit out all that nasty green stuff that comes up when we cough, it removes germs.  In effect DXM has no healing action.

 

Hallucinations, visions, out of body etc - A document entitled "The DXM FAQ," by William E. White, classifies dextromethorphan's high-dose effects into four plateaus, each defined by a dosing range. The dosages are specified in ratios of milligrams (of the drug) per kilogram (of one's body mass). Doses are experientially, not scientifically derived.

An experiment, in which a dose  of 2.5-7.5 mg/kg was given every three hours for 9–12 hours,  produced visual and auditory hallucinations, which were very very unpleasant.  Most ‘upper plateau experiences’ involve forms of catalepsy.  So called Fourth plateau doses are fully dissociative (just below anaesthetic). Dosages in these ranges are dangerous - that is life threatening.

Repeated doses of DXM can produce very unpleasant side effects and can induce psychosis.   If you repeatedly and frequently use DXM you may get permanent memory loss and loss of reason.

It is possible to overdose on DXM without realising you are doing it.  DXM is converted into the active metabolite dextrorphan in the liver by the cytochrome P450 enzyme CYP2D6.  Approximately 1 in 10 of the caucasian population has little or no CYP2D6 enzyme activity leading to long lived high drug levels.  The duration of action and effects of dextromethorphan can be increased by as much as three times.

A large number of medications are potent inhibitors of CYP2D6. Some types of medications known to inhibit CYP2D6 include certain SSRI and tricyclic antidepressants, some antipsychotics, and the commonly-available antihistamine diphenhydramine -- also known as Benadryl. There exists, therefore, the potential of interactions between dextromethorphan and medications that inhibit this enzyme.

References and further reading

This LINK takes you to a youtube video

Related observations