Carbogen, also calledMeduna's Mixture after its inventorLadislas Meduna, is a mixture ofcarbon dioxide andoxygen gas. Meduna's original formula was 30% CO2 and 70% oxygen, but the term carbogen can refer to any mixture of these two gases, from 1.5%[1] to 50%[2] CO2. It is ahallucinogen.[3][4]
When carbogen is inhaled, the increased level of carbon dioxide causes a perception, both psychological and physiological, ofsuffocation because the brain interprets an increase in blood carbon dioxide as a decrease in oxygen level,[5] which would generally be the case under natural circumstances. Inhalation of carbogen causes the body to react as if it were not receiving sufficient oxygen: breathing quickens and deepens,heart rate increases, and cells releasealkalinebuffering agents to removecarbonic acid from the bloodstream.
Carbogen was once used in psychology andpsychedelic psychotherapy to determine whether a patient would react to analtered state of consciousness or to a sensation of loss of control.[6] Individuals who reacted especially negatively to carbogen were generally not administered otherpsychotherapeutic drugs for fear of similar reactions. Meduna administered carbogen to his patients to induceabreaction, which, with proper preparation and administration, he found could help clients become free of their neuroses. Carbogen users are said to have discovered unconscious contents of their minds, with the experience clearing away repressed material and freeing the subject for a smoother, more profound psychedelic experience.[5]
One subject reported:"After the second breath came an onrush of color, first a predominant sheet of beautiful rosy-red, following which came successive sheets of brilliant color and design, some geometric, some fanciful and graceful …. Then the colors separated; my soul drawing apart from the physical being, was drawn upward seemingly to leave the earth and to go upward where it reached a greater Spirit with Whom there was a communion, producing a remarkable, new relaxation and deep security."[7]
Carbogen is rarely used in therapy anymore, largely due to the decline inpsychedelic psychotherapy.
A carbogen mixture of 95% oxygen and 5% carbon dioxide can be used as part of the early treatment ofcentral retinal artery occlusion. On this same premise it has also been proposed to be used in the management of sudden sensorineural hearing loss which can increase the blood flow to the inner ear and also possibly relieve the internal auditory artery spasm.
Carbogen is used in biology research to studyin vivo oxygen and carbon dioxide flows,[8] as well as to oxygenate theaCSF solution and stabilize the pH to about 7.4 in research on acute brain slices.
Its use in combination withnicotinamide is also being investigated in conjunction withradiation therapy in the treatment strategy of certain cancers.[9] Because increased tumor oxygenation improves the cell-killing effects of radiation, it is thought that the inhalation of these agents during radiation therapy could increase its effectiveness.