Related Issues – Vol 6, No. 3 – October 2008

Addiction, October 2008
(Addiction, 103, 1671-1677) Bloor, Want, Spanel & Smith, UK and Czech Republic

Ammonia release from heated ’street’ cannabis leaf and its potential toxic effects on cannabis users

“Studies of the effect of cannabis smoking on respiratory and general health indicate that the use of cannabis alone has an adverse effect on respiratory health and that when used with tobacco the negative effects are additive…Awareness of the risks of inhaling the smoke directly from the burning cannabis has led to the development of a number of alternative methods of delivery, which are claimed to be safer than direct smoking.”

“For ’street’ cannabis ammonia was present in the air samples from devices at levels approaching 200 parts per million.” [Smoke from standard 3% THC NIDA cannabis cigarettes was also analyzed but had peak levels of only 10 parts per million of ammonia. Street cannabis, particularly that purported to be for "medicinal" use, typically exceeds 10% THC.]

Conclusion: Awareness of the risks of inhaling the smoke directly from burning cannabis has led to the development of a number of alternative methods of delivery [water bongs, low temperature vaporizers, etc.], which are claimed to be safer than direct smoking. Ammonia at toxic levels is produced from heating ’street’ cannabis in these commercially available devices. Thus, the use of these devices to deliver ’street’ cannabis is now open to question and further research is needed to investigate their safety.”

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Substance Use & Misuse, 2008
(Substance Use & Misuse, 43:1326-1339) Staffan Eksborg and Jovan Rajs; Sweden

Morbidity – Causes and Manners of Death Among Users of heroin, Methadone, Amphetamine, and Cannabis in Relation to Postmortem Chemical Tests for Illegal Drugs

This is the result of a 12-year medicolegal investigation of deceased illegal drug users (ILDU) in Stockholm, Sweden, classified on the basis of postmortem chemical tests. The study “showed noticeable variations in causes and manners of death as well as the distribution of suicide methods.”

The authors noted: “We did not anticipate the large relative proportion for fatal traffic crashes among the ‘cannabis only’ users…the relative proportion of fatal traffic crashes was 57% among the 30 cannabis only users as compared to all decedents with evidence of recent cannabis use, for whom the relative proportion was 16%. . . This study also revealed differences among the suicide methods chosen in relation to results of postmortem drug tests. Non-violent suicide methods most often were chosen by heroin and methadone users (84% and 62%, respectively); this was the only choice for suicide when one of these drugs was the only illegal drug detected….However, it is of note that…the choice of extremely violent suicide methods was quite substantial among cannabis users, 45% (54% for cannabis only users).

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Pain Medicine
Anesthesiology 2008; 109:101-10, Kraft, Frickey et al, Austria
(a double-blind, crossover study in 18 healthy female volunteers)

Lack of Analgesia by Oral Standardized Cannabis Extract on Acute Inflammatory Pain and Hyperalgesia in Volunteers.

“Besides studies with smoked cannabis, no controlled experimental clinical trials on the analgesic (pain relieving) efficacy of oral cannabis extract or THC on acute inflammatory pain and hyperalgesia in humans have been published to date. Therefore, the current study was designed to detect a potential analgesic activity of oral THC-standardized cannabis extract by two different and well-established human models of acute inflammatory pain and hyperalgesia, i.e., the sunburn model and the intradermal injection of capsaicin.”

Conclusion: “No analgesic or antihyperalgesic activity of cannabis extract was found in the experiments. Moreover, the results even point to the development of a hyperalgesic (more painful) state under cannabinoids. Together with previous data, the current results suggest that cannabinoids are not effective analgesics for the treatment of acute nociceptive (inflammatory) pain in humans.

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The Journal of Pain, Vol. 9, No. 6, 2008; pp 506-521
Wilsey, Marcotte et al, UC Davis, Davis, California

A Randomized, Placebo-Controlled, Crossover Trial of Cannabis Cigarettes in Neuropathic Pain

The authors “conducted a double-blinded, placebo-controlled, crossover study evaluating the analgesic efficacy of smoking cannabis for neuropathic pain. Thirty-eight patients with central and peripheral neuropathic pain [CRPS] underwent a standardized procedure for smoking [NIDA provided marijuana cigarettes] either high-dose (7%) low-dose (3.5%), or placebo cannabis.”

Patients were all cannabis users but refrained from use for 30 days before the study which excluded any candidate with a history of depression, schizophrenia or bipolar depression “because the effects of cannabis can exacerbate mental illness and have been linked to an increase in the risk of suicide. . . . Undesirable consequences of smoking cannabis were clearly identifiable. . . However, beyond the benign psychoactive effects, administration of cannabis may be deleterious in that it impairs cognition.”

The authors also noted that their “study indicates that modest declines in cognitive performance occur with cannabis, particularly in learning and recall, and especially at higher doses. In combination with the deficits in baseline neurocognitive performance, however, cannabis compounds this problem. This finding necessitates caution in the prescribing of medical marijuana for neuropathic pain, especially in instances in which learning and memory are integral to a patient’s work and lifestyle.”

“Further vigilance is warranted in young patients because cannabis use in adolescence increases the risk of later schizophrenia-like psychoses, especially in genetically susceptible individuals. There is an increased risk of psychosis in those who have ever used cannabis…and a dose-response effect, with greater risk in subgroups consuming cannabis very frequently.

“In addition to the issues discussed above, the noxious pyrolytic byproducts released through combustion remain a public health deterrent to the use of smoked cannabis.

Conclusion: Despite the above findings, the authors concluded that “In general, side effects and changes in mood were relatively inconsequential. These findings are consistent with the observation that many patients find treatment with cannabis to be a satisfactory experience.”

Material used in this publication has been reviewed and commented on by

William M. Bennett, M.D., MACP
Medical Director Transplant Services, Legacy Hospital Systems, Portland, OR
Editor, Clinical Journal American Society of Nephrology,
Professor of Medicine and Clinical Pharmacology, retired, Oregon Health & Sciences University.