Please note, there is still a great deal of research to be done concerning the effects of marijuana on the health of humans.
Marijuana has often been touted as one of the safest recreational substances available. This is perhaps true; many reputable scientific studies support the conclusion that cocaine, heroine, alcohol, and even cigarettes are more dangerous to the user’s health than marijuana. Due to it’s pharmacological properties, thirty-six states have permitted its use as a therapeutic drug for, among others, those suffering from AIDS; various painful, incurable and debilitating illnesses; the harmful side effects of cancer chemotherapy, and glaucoma. Additional research is being conducted concerning the use of marijuana on the treatment of anxiety and mental disorders.
REPORT OF THE COUNCIL ON SCIENCE AND PUBLIC HEALTH
As of 2001, the Council had concluded that sufficient evidence existed to support further research on the potential use of marijuana:
- In HIV-infected patients with cachexia, neuropathy, or chronic pain, or who are suffering adverse effects from medication, such as nausea, vomiting, and peripheral neuropathy, that impede compliance with antiretroviral therapy;
- In patients undergoing chemotherapy, especially those being treated for mucositis, nausea, and anorexia, and those patients who do not obtain adequate relief from either acute or delayed emetic episodes from standard therapy;
- To potentiate the analgesic effects of opioids and to reduce their emetic effects in the treatment of postoperative, traumatic, or cancer pain;
- In patients suffering from spasticity or pain due to spinal cord injury, or neuropathic or central pain syndromes; and
- In patients with chronic pain and insomnia.
Cannabis is one of the oldest psychotropic drugs in human history. Originating from central Asia, and then spreading to China and India, the first modern description of its pharmacological properties was provided by an Irish physician (William O’Shaughnessy) in 1839. First listed in the United States Dispensary in 1854, cannabis was promoted for a variety of conditions based on its putative analgesic, sedative, anti-inflammatory, antispasmodic, anti-asthmatic, and anticonvulsant properties. Many cannabis-containing oral extracts and tinctures were subsequently manufactured. Interest in the medical use of cannabis waned somewhat in the late nineteenth and early twentieth centuries with the advent of opiates, barbiturates, chloral hydrate, and aspirin and the widespread availability of hypodermic syringes for injection of water-soluble compounds. Nevertheless, cannabis remained available in the British Pharmacopoeia in extract and tincture form until 1971.
The U.S. government and popular media began condemning the use of smoked cannabis in the 1930s, linking its use to homicidal mania. The Marihuana Tax Act of 1937 introduced the first federal restrictions on marijuana.At the time, the AMA was virtually alone in opposing passage of the Marihuana Tax Act. The AMA believed that objective data were lacking on the harmful effects of marijuana, and that passage of the Act would impede future investigations into its potential medical uses.
In 1964, delta-9-tetrahydrocannabinol (hereafter referred to as THC) was identified as the primary psychoactive cannabinoid in Cannabis sativa (see below) and successfully synthesized.Receptors in the brain and periphery that bind THC (cannabinoid receptors) were discovered in the early 1990s, and the identification of endogenous compounds that act at cannabinoid receptors (endocannabinoids) soon followed.
Resolution 229 (A-09) makes reference to a “Presidential/Executive” order. To the Council’s knowledge no such order exists.
Currently cannabinoids are “available” in three different categories: FDA approved oral preparations of THC (Dronabinol; Marinol®) and a synthetic analogue (Nabilone; Cesament®); Cannabis sativa extracts (e.g., Nabiximols [Sativex®], [Cannador®]) not currently approved in the U.S.; and crude botanical sources made available under state laws. Since 2001, systematic reviews have been conducted on smoked cannabis and other cannabinoids (mostly oral THC and botanical extracts).
- Cancer chemotherapy. Three randomized, double-blind, controlled trials involving a total of 43 patients have evaluated the efficacy of smoked cannabis to alleviate nausea and vomiting accompanying cancer chemotherapy; one directly compared smoked cannabis with oral THC but was never published in a peer reviewed journal. These trials revealed a modest antiemetic effect of smoked cannabis greater than placebo.
- Appetite stimulation. Three randomized, placebo-controlled trials involving a total of 97 HIV+ adult patients have compared the effects of smoked cannabis with oral THC or dronabinol; two used a “within subjects” design. Generally, the effects of smoked cannabis (2% or 3.9% THC) were comparable to oral cannabinoids in increasing caloric intake and triggering weight gain, although the dose of oral THC was substantially higher than normally recommended.HIV viral load and the pharmacokinetics of concurrent protease inhibitors were unaffected over a three week period.
- Pain Management. Two randomized, double-blind, placebo-controlled trials involving a total of 89 patients with HIV-associated peripheral neuropathy, and one (n = 38) involving an experimental pain model (capsaicin) have been reported. The latter was a randomized, double-blind, placebo-controlled crossover trial in 15 healthy volunteers examining the effects of cannabis cigarettes (2%, 4%, or 8%) on pain and cutaneous hyperalgesia induced by intradermal capsaicin. The medium dose exhibited delayed analgesia, significantly inhibiting capsaicin-induced pain at 45 minutes after drug exposure; the low dose was ineffective, and the high dose increased capsaicin- induced pain at 45 minutes. Smoked cannabis did not significantly affect acute painful heat, cold, and mechanical thresholds.
In patients with HIV-associated neuropathic pain, cannabis cigarettes of varying concentration and number consumed over a 5-day period significantly reduced pain intensity. Approximately half of patients experienced more than a 30% reduction, which is a standard benchmark for efficacy. Analysis of the number-needed-to-treat also compared favorably with historic values associated with other drugs used to treat neuropathic pain.
Generally, side effects typically attributable to THC (anxiety, sedation, confusion, dizziness, fatigue, tachycardia, dry mouth) were noticeable in these studies but were tolerable and not considered dose-limiting. The use of higher potency cigarettes was more likely to be associated with drug-related cognitive decline on psychological testing.
The overall evaluation of the clinical effects of smoked cannabis in stimulating appetite and relieving neuropathic pain (and to a certain degree, nausea) correlates with patterns of use reported in surveys of HIV+ patients. The overall evaluation of the clinical effects of smoked cannabis in stimulating appetite and relieving neuropathic pain (and to a certain degree, nausea) correlates with patterns of use reported in surveys of HIV+ patients.
- Multiple Sclerosis and Spasticity. Surveys reveal that 36% to 68% of patients with multiplesclerosis have experimented with smoked cannabis for symptom relief, and approximately 15% are continuing users. Two randomized, double-blind, placebo-controlled trials involving a total of 40 patients have been reported in patients with multiple sclerosis and spasticity.
- Glaucoma. In one randomized, double-blind, placebo-controlled crossover study of 18 adults with glaucoma, smoking one cannabis cigarette (2% THC) caused a significant reduction in intraocular pressure, along with alterations in sensory perception, tachycardia/palpitations, and postural hypotension.
Determining the adverse effects of smoked cannabis used as medicine is problematic since only short-term controlled trials havebeen conducted. Most researchon the harmful consequences of cannabis use has been conducted in simulated laboratory environments and in individuals who use cannabis for nonmedical purposes. One independenthealth assessment of four of the remaining seven patients obtaining cannabis cigarettes through the federal government’s Compassionate Use Treatment IND (see Council report from 1997), showed no demonstrable adverse outcomes related to their chronic medicinal cannabis use. Most data on adverse effects has come from observational population-based cohort studies of recreational cannabis users, an unknown portion of whom may be using the substance for medicinal purposes. Adverse reactions observed in short-term randomized, placebo-controlled trials of smoked cannabis to date are mostly mild without substantial impairment. A systematic review of the safety studies on medical cannabinoids published over the last 40 years (not including studies on smoked cannabis) found thatshort term use was associated with a number of adverse events, but less than 4% were considered serious.
Most data on adverse effects has come from observational population-based cohort studies of recreational cannabis users, an unknown portion of whom may be using the substance for medicinal purposes. Adverse reactions observed in short-term randomized, placebo-controlled trials of smoked cannabis to date are mostly mild without substantial impairment. A systematic review of the safety studies on medical cannabinoids published over the last 40 years (not including studies on smoked cannabis) found that short term use was associated with a number of adverse events, but less than 4% were considered serious.
Whether or not cannabis is a “gateway” drug to other substance misuse is controversial and whether the medical availability of cannabis would increase drug abuse is not known. Analysis of trends in emergency room visits for marijuana do not support the view that state authorization for medical cannabis use leads to increased signals of substance misuse. The IOM concluded that marijuana use is not the cause or even the most serious predictor of serious substance use disorders. A systematic review of longitudinal studies on the use of cannabis concluded its use was consistently associated with reduced educational achievement and the use of other drugs, but not other measures of psychosocial harm.
The IOM concluded that marijuana use is not the cause or even the mostserious predictor of serious substance use disorders. A systematic review of longitudinal studies on the use of cannabis concluded its use was consistently associated with reduced educational achievement and the use of other drugs, but not other measures of psychosocial harm.
Like tobacco, chronic cannabis smoking is associatedwith markers of lung damage and increased symptoms of chronic bronchitis. However, results of a population-based case control study of cannabis smokers found no evidence of increased riskfor lung cancer or other cancers affecting the oral cavity and airway. Another population-based case-control study of marijuana use and head and neck squamous cell carcinoma (HNSCC) concluded that moderate marijuana use is associated with reduced risk of HNSCC. Furthermore, although smoking cannabis and tobacco may synergistically increase the risk of respiratory symptoms and COPD, smoking only cannabis is not associated with an increased risk of developing COPD.
The use of a vaporizer is associated with higher plasma THC concentrations than smoking marijuana cigarettes, little if any carbon monoxide production, and significantly fewer triggered respiratory symptoms.
Despite more than 30 years of clinical research, only a small number of randomized, controlled trials have been conducted on smoked cannabis. These trials were short term and involved a total of ~300 patients. Results of these trials indicate smoked cannabis reduces neuropathic pain, improves appetite and caloric intake especially inpatients with reduced muscle mass, and may relieve spasticity and pain in patients with multiple sclerosis. Substantially better alternatives than smoked cannabis are available to treat patients with glaucoma or chemotherapy-induced nausea and vomiting.
Many legal pharmaceutical products that are used for pain relief, palliation, and sleep induction have more serious acute toxicities than marijuana, including death. Witness the evolving series of steps that the FDA has taken in recent months to address the inappropriate use and diversion of certain long-acting Schedule II opioid drugs. However, the patchwork of state-based systems that have been established for “medical marijuana” is woefully inadequate in establishing even rudimentary safeguards that normally would be applied to the appropriate clinical use of psychoactive substances.
The AMA supports the concept of drug approval byscientific and regulatory review to establish safety and efficacy, combined with appropriate standards for identity, strength, quality, purity, packaging, and labeling, rather than by ballot initiative or state legislative action. The future of cannabinoid-based medicine lies in the rapidly evolving field of botanical drug substance development, as well as the design of molecules that target various aspects of the endocannabinoid system. To the extent that rescheduling marijuana out of Schedule I will benefit this effort, such a move can be supported. In the meantime, physicians who comply with their ethical obligations to “first do no harm” and to “relieve pain and suffering” should be protected in their endeavors, including advising and counseling their patients on the use of cannabis for therapeutic purposes.
Marijuana May Fight Lung Tumors
WebMD Health News
In lab and mouse studies, the compound, known as THC, cut lung tumor growth in half and helped prevent the cancer from spreading, says Anju Preet, PhD, a Harvard University researcher in Boston who tested the chemical.
While a lot more work needs to be done, “the results suggest THC has therapeutic potential,” she tells WebMD.
The findings were presented at the annual meeting of the American Association for Cancer Research.
The finding builds on the recent discovery of the body’s own cannabinoid system, Preet says. Known as endocannabinoids, the natural cannabinoids stimulate appetite and control pain and inflammation.
THC seeks out, attaches to, and activates two specific endocannabinoids that are present in high amounts on lung cancer cells, Preet says. This revs up their natural anti-inflammatory properties. Inflammation can promote the growth and spread of cancer.
In the new study, the researchers first demonstrated that THC inhibited the growth and spread of cells from two different lung cancer cell lines and from patient lung tumors. Then, they injected THC into mice that had been implanted with human lung cancer cells. After three weeks, tumors shrank by about 50%, compared with tumors in untreated mice.
Preet notes that animals injected with THC seem to get “high,” showing signs of clumsiness and getting the munchies. “You would expect to see the same thing in humans, so if this work does pan out, getting the dose right is going to be all important,” she says.
Paul B. Fisher, PhD, a professor of clinical pathology at Columbia University, says that though the work is “interesting,” it’s still very early.
“The issue with using a drug of this type becomes the window of concentration that will be effective. Can you physiologically achieve what you want without causing unwanted effects?” he tells WebMD.
Marijuana And Lungs: Study Finds Drug Doesn’t Do Same Kind Of Damage As Tobacco
CHICAGO — Smoking a joint once a week or a bit more apparently doesn’t harm the lungs, suggests a 20-year study that bolsters evidence that marijuana doesn’t do the kind of damage tobacco does.
The results, from one of the largest and longest studies on the health effects of marijuana, are hazier for heavy users – those who smoke two or more joints daily for several years. The data suggest that using marijuana that often might cause a decline in lung function, but there weren’t enough heavy users among the 5,000 young adults in the study to draw firm conclusions.
Still, the authors recommended “caution and moderation when marijuana use is considered.”
Marijuana is an illegal drug under federal law although some states allow its use for medical purposes.
The study by researchers at the University of California, San Francisco, and the University of Alabama at Birmingham was released Tuesday by the Journal of the American Medical Association.
The findings echo results in some smaller studies that showed while marijuana contains some of the same toxic chemicals as tobacco, it does not carry the same risks for lung disease.
It’s not clear why that is so, but it’s possible that the main active ingredient in marijuana, a chemical known as THC, makes the difference. THC causes the “high” that users feel. It also helps fight inflammation and may counteract the effects of more irritating chemicals in the drug, said Dr. Donald Tashkin, a marijuana researcher and an emeritus professor of medicine at the University of California, Los Angeles. Tashkin was not involved in the new study.
Study co-author Dr. Stefan Kertesz said there are other aspects of marijuana that may help explain the results.
Unlike cigarette smokers, marijuana users tend to breathe in deeply when they inhale a joint, which some researchers think might strengthen lung tissue. But the common lung function tests used in the study require the same kind of deep breathing that marijuana smokers are used to, so their good test results might partly reflect lots of practice, said Kertesz, a drug abuse researcher and preventive medicine specialist at the Alabama university.
The study authors analyzed data from participants in a 20-year federally funded health study in young adults that began in 1985. Their analysis was funded by the National Institute on Drug Abuse.
The study randomly enrolled 5,115 men and women aged 18 through 30 in four cities: Birmingham, Chicago, Oakland, Calif., and Minneapolis. Roughly equal numbers of blacks and whites took part, but no other minorities. Participants were periodically asked about recent marijuana or cigarette use and had several lung function tests during the study.
Overall, about 37 percent reported at least occasional marijuana use, and most users also reported having smoked cigarettes; 17 percent of participants said they’d smoked cigarettes but not marijuana. Those results are similar to national estimates.
On average, cigarette users smoked about 9 cigarettes daily, while average marijuana use was only a joint or two a few times a month – typical for U.S. marijuana users, Kertesz said.
The authors calculated the effects of tobacco and marijuana separately, both in people who used only one or the other, and in people who used both. They also considered other factors that could influence lung function, including air pollution in cities studied.
The analyses showed pot didn’t appear to harm lung function, but cigarettes did. Cigarette smokers’ test scores worsened steadily during the study. Smoking marijuana as often as one joint daily for seven years, or one joint weekly for 20 years was not linked with worse scores. Very few study participants smoked more often than that.
Like cigarette smokers, marijuana users can develop throat irritation and coughs, but the study didn’t focus on those. It also didn’t examine lung cancer, but other studies haven’t found any definitive link between marijuana use and cancer.
Science Says: Lungs Love Weed
Twenty-year study suggests smoking marijuana is healthier than tobacco.
Breathe easy, tokers. Smoking marijuana in moderate amounts may not be so bad for your lungs, after all.
A new study, published in this month’s Journal of the American Medical Association, tested the lung function of over 5,000 young adults between 18 and 30. After 20 years of testing, researchers found some buzzworthy results: regular marijuana smokers (defined by up to a joint a day for seven years) had no discernable impairment in lung activity from non-smokers.
In fact, researchers were surprised to find marijuana smokers performed slightly better than both smokers and non-smokers on the lung performance test. Why? The most likely explanation seems to be that the act of inhaling marijuana—holding each puff in for as long as possible—is a lot like a pulmonary function test, giving marijuana smokers an edge over their cigarette smoking counterparts.
For most of human existence, cannabis has been considered a medicine. Queen Victoria used it to alleviate her menstrual cramps. Extracts were prescribed by doctors and available at every pharmacy in the U.S. According to Fast Food Nation author Eric Schlosser, attitudes toward cannabis only shifted when Americans began to notice and object to its use by immigrants around the turn of the 20th century. Said Schlosser in a PBS interview:
“What’s interesting is if you look at origins of the marijuana prohibition in this country, it coincides with a rise in anti-immigrant sentiment. . . really since the early years of this century, the war on marijuana has been much more a war on the sort of people who smoke it, be they Mexicans or blacks or jazz musicians or beatniks or hippies or hip-hop artists. It’s really been a war on nonconformists and the laws against marijuana have been used as a way of reasserting what are seen as traditional American values.”
Attitudes are changing, however. Sixteen states now offer medicinal weed legally for patients, and the number is growing. More students are now smoking marijuana than binge drinking or smoking cigarettes. Weed-friendly communities like Oaksterdam, unthinkable a decade or two ago, are sprouting up and campaigning to have marijuana revenue regulated and taxed like alcohol.
- Viewpoints: Science supporting medicinal pot is clear (sacbee.com)
- Five Scientific Conclusions About Cannabis That The Mainstream Media Doesn’t Want You To Know (talesfromthelou.wordpress.com)
- Israelis develop ‘highless’ marijuana (thesciencebulletin.wordpress.com)
- Medical Marijuana: Clearing Away the Smoke (cannabee.wordpress.com)
- Research backs up claims of medical marijuana’s benefits (pasadenamarijuanaevaluations.com)
- Chemists discover cannabis ‘pharma factory’ – Phys.Org (phys.org)
- THC for TLC? (mikewatkinsinvestigates.wordpress.com)
- Mom With Cerebral Palsy Transformed By Pot (VIDEO) (huffingtonpost.com)
- What Is Tetrahydrocannabinol? An Overview (cancer.answers.com)
- The Life of THC (chem.answers.com)