Медициналық марихуана: зерттеулер мен тәуекелдер

Marijuana used medicinally

Medical cannabis, or medical marijuana (MMJ), is cannabis and cannabinoids that are prescribed by physicians for their patients. The use of cannabis as medicine has not been rigorously tested due to production and governmental restrictions, resulting in limited clinical research to define the safety and efficacy of using cannabis to treat diseases. Preliminary evidence has indicated that cannabis might reduce nausea and vomiting during chemotherapy and reduce chronic pain and muscle spasms. Short term use increases the risk of minor and major adverse effects. Some American medical organizations have requested removal of cannabis from the list of Schedule I controlled substances maintained by the United States federal government, followed by regulatory and scientific review. A cannabis plant includes more than 400 different chemicals, of which about 70 are cannabinoids. In comparison, typical government approved medications contain only one or two chemicals.) of cannabis products.

Overall, research into the health effects of medical cannabis has been of low quality and it is not clear whether it is a useful treatment for any condition, or whether harms outweigh any benefit. There is no consistent evidence that it helps with chronic pain and muscle spasms. When usual treatments are ineffective, cannabinoids have also been recommended for anorexia, arthritis, glaucoma,

It is unclear whether American states might be able to mitigate the adverse effects of the opioid epidemic by prescribing medical cannabis as an alternative pain management drug. Cannabis should not be used in pregnancy.

Research analyzing data from the National Health and Nutrition Examination Survey (NHANES) did not find significant differences in sleep duration between cannabis users and non users. This suggests that while some individuals may perceive benefits from cannabis use in terms of sleep, it may not significantly change overall sleep patterns across the general population. A review of literature up to 2018 indicates that cannabidiol (CBD) may have therapeutic potential for the treatment of insomnia. CBD, a non psychoactive component of cannabis, is of particular interest due to its potential to influence sleep without the psychoactive effects associated with tetrahydrocannabinol (THC).

Medical cannabis is somewhat effective in chemotherapy induced nausea and vomiting (CINV) and may be a reasonable option in those who do not improve following preferential treatment. but these are used less frequently because of side effects including dizziness, dysphoria, and hallucinations. Long term cannabis use may cause nausea and vomiting, a condition known as cannabinoid hyperemesis syndrome (CHS). A 2016 Cochrane review said that cannabinoids were "probably effective" in treating chemotherapy induced nausea in children, but with a high side effect profile (mainly drowsiness, dizziness, altered moods, and increased appetite). Less common side effects were "ocular problems, orthostatic hypotension, muscle twitching, pruritus, vagueness, hallucinations, lightheadedness and dry mouth".

Evidence is lacking for both efficacy and safety of cannabis and cannabinoids in treating patients with HIV/AIDS or for anorexia associated with AIDS. As of 2013, current studies suffer from the effects of bias, small sample size, and lack of long term data.

A 2021 review found little effect of using non inhaled cannabis to relieve chronic pain. A 2011 review considered cannabis to be generally safe, and it appears safer than opioids in palliative care. A 2022 review concluded the pain relief experienced after using medical cannabis is due to the placebo effect, especially given widespread media attention that sets the expectation for pain relief.

Cannabis' efficacy is not clear in treating neurological problems, including multiple sclerosis (MS) and movement problems. A 2012 review found no problems with tolerance, abuse, or addiction. In the United States, cannabidiol, one of the cannabinoids found in the marijuana plant, has been approved for treating two severe forms of epilepsy, Lennox Gastaut syndrome and Dravet syndrome.

A 2019 systematic review found that there is a lack of evidence that cannabinoids are effective in treating depressive or anxiety disorders, attention deficit hyperactivity disorder (ADHD), Tourette syndrome, post traumatic stress disorder, or psychosis. Research indicates that cannabis, particularly CBD, may have anxiolytic (anxiety reducing) effects. A study found that CBD significantly reduced anxiety during a simulated public speaking test for individuals with social anxiety disorder. However, the relationship between cannabis use and anxiety symptoms is complex, and while some users report relief, the overall evidence from observational studies and clinical trials remains inconclusive. Cannabis is often used by people to cope with anxiety, yet it is crucial to note that the efficacy and safety of cannabis for treating anxiety disorders need further investigation. Cannabis use, especially at high doses, is associated with a higher risk of psychosis, particularly in individuals with a genetic predisposition to psychotic disorders like schizophrenia. Some studies have shown that cannabis can trigger a temporary psychotic episode, which may increase the risk of developing a psychotic disorder later. The impact of cannabis on depression is less clear. Some studies suggest a potential increase in depression risk among adolescents who use cannabis, though findings are inconsistent across studies. Typically, adverse effects of medical cannabis use are not serious; they include tiredness, dizziness, increased appetite, and cardiovascular and psychoactive effects. Other effects can include impaired short term memory; impaired motor coordination; altered judgment; and paranoia or psychosis at high doses. Tolerance to these effects develops over a period of days or weeks. The amount of cannabis normally used for medicinal purposes is not believed to cause any permanent cognitive impairment in adults, though long term treatment in adolescents should be weighed carefully as they are more susceptible to these impairments. Withdrawal symptoms are rarely a problem with controlled medical administration of cannabinoids. The ability to drive vehicles or to operate machinery may be impaired until a tolerance is developed. Although supporters of medical cannabis say that it is safe,

Recreational use of cannabis is associated with cognitive deficits, especially for those who begin to use cannabis in adolescence. as of 2021 there is a lack of research into long term cognitive effects of medical use of cannabis, but one 12 month observational study reported that "MC patients demonstrated significant improvements on measures of executive function and clinical state over the course of 12 months".

Exposure to THC can cause acute transient psychotic symptoms in healthy individuals and people with schizophrenia. A 2005 meta analysis concluded that adolescent use of cannabis increases the risk of psychosis, and that the risk is dose related. A 2004 literature review on the subject concluded that cannabis use is associated with a two fold increase in the risk of psychosis, but that cannabis use is "neither necessary nor sufficient" to cause psychosis. A French review from 2009 came to a conclusion that cannabis use, particularly that before age 15, was a factor in the development of schizophrenic disorders.

The genus Cannabis contains two species which produce useful amounts of psychoactive cannabinoids: Cannabis indica and Cannabis sativa, which are listed as Schedule I medicinal plants in the US; – chemical compounds that interact with cannabinoid receptors in the brain. The most psychoactive cannabinoid found in the cannabis plant is tetrahydrocannabinol (or delta 9 tetrahydrocannabinol, commonly known as THC). CB1 and CB2 are the primary cannabinoid receptors responsible for several of the effects of cannabinoids, although other receptors may play a role as well. Both belong to a group of receptors called G protein coupled receptors (GPCRs). CB1 receptors are found in very high levels in the brain and are thought to be responsible for psychoactive effects. CB2 receptors are found peripherally throughout the body and are thought to modulate pain and inflammation.

Cannabinoid absorption is dependent on its route of administration. Inhaled and vaporized THC have similar absorption profiles to smoked THC, with a bioavailability ranging from 10 to 35%. Oral administration has the lowest bioavailability of approximately 6%, variable absorption depending on the vehicle used, and the longest time to peak plasma levels (2 to 6 hours) compared to smoked or vaporized THC. Similar to THC, CBD has poor oral bioavailability, approximately 6%. The low bioavailability is largely attributed to significant first pass metabolism in the liver and erratic absorption from the gastrointestinal tract. However, oral administration of CBD has a faster time to peak concentrations (2 hours) than THC. Rectal administration in monkeys doubled bioavailability to 13.5% and achieved peak blood concentrations within 1 to 8 hours after administration.

Like cannabinoid absorption, distribution is also dependent on route of administration. Smoking and inhalation of vaporized cannabis have better absorption than do other routes of administration, and therefore also have more predictable distribution. THC is highly protein bound once absorbed, with only 3% found unbound in the plasma. It distributes rapidly to highly vascularized organs such as the heart, lungs, liver, spleen, and kidneys, as well as to various glands. Low levels can be detected in the brain, testes, and unborn fetuses, all of which are protected from systemic circulation via barriers. THC further distributes into fatty tissues a few days after administration due to its high lipophilicity, and is found deposited in the spleen and fat after redistribution.

Delta 9 THC is the primary molecule responsible for the effects of cannabis. Delta 9 THC is metabolized in the liver and turns into 11 OH THC. 11 OH THC is the first metabolic product in this pathway. Both Delta 9 THC and 11 OH THC are psychoactive. The metabolism of THC into 11 OH THC plays a part in the heightened psychoactive effects of edible cannabis. Next, 11 OH THC is metabolized in the liver into 11 COOH THC, which is the second metabolic product of THC. 11 COOH THC is not psychoactive. After delta 9 THC is hydroxylated into 11 OH THC via CYP2C9, CYP2C19, and CYP3A4, it undergoes phase II metabolism into more than 30 metabolites, a majority of which are products of glucuronidation. Approximately 65% of THC is excreted in feces and 25% in the urine, while the remaining 10% is excreted by other means. whereas for CBD it is 18 to 32 hours. Similar to delta 9 THC, a majority of CBD is excreted in feces and some in the urine.

Smoking has been the means of administration of cannabis for many users, but it is not suitable for the use of cannabis as a medicine. It was the most common method of medical cannabis consumption in the US .

Cannabis, called má 麻 (meaning "hemp; cannabis; numbness") or dàmá 大麻 (with "big; great") in Chinese, was used in Taiwan for fiber starting about 10,000 years ago. The botanist Hui lin Li wrote that in China, "The use of Cannabis in medicine was probably a very early development. Since ancient humans used hemp seed as food, it was quite natural for them to also discover the medicinal properties of the plant." Emperor Shen Nung, who was also a pharmacologist, wrote a book on treatment methods in 2737 BCE that included the medical benefits of cannabis. He recommended the substance for many ailments, including constipation, gout, rheumatism, and absent mindedness. Cannabis is one of the 50 "fundamental" herbs in traditional Chinese medicine. The Ebers Papyrus (c. 1550 BCE) from Ancient Egypt describes medical cannabis. The ancient Egyptians used hemp (cannabis) in suppositories for relieving the pain of hemorrhoids. Surviving texts from ancient India confirm that cannabis' psychoactive properties were recognized, and doctors used it for treating a variety of illnesses and ailments, including insomnia, headaches, gastrointestinal disorders, and pain, including during childbirth. The Ancient Greeks used cannabis to dress wounds and sores on their horses, and in humans, dried leaves of cannabis were used to treat nose bleeds, and cannabis seeds were used to expel tapeworms.

Cannabis seeds may have been used for food, rituals or religious practices in ancient Europe and China. Harvesting the plant led to the spread of cannabis throughout Eurasia about 10,000 to 5,000 years ago, with further distribution to the Middle East and Africa about 2,000 to 500 years ago. They are cultivars of the plant that originated in one specific region. Widely cultivated strains of cannabis, such as "Afghani" or "Hindu Kush", are indigenous to the Pakistan and Afghanistan regions, while "Durban Poison" is native to Africa.

An Irish physician, William Brooke O'Shaughnessy, is credited with introducing cannabis to Western medicine. O'Shaughnessy discovered cannabis in the 1830s while living abroad in India, where he conducted numerous experiments investigating the drug's medical utility (noting in particular its analgesic and anticonvulsant effects). He returned to England with a supply of cannabis in 1842, after which its use spread through Europe and the United States. In 1845 French physician Jacques Joseph Moreau published a book about the use of cannabis in psychiatry. In 1850 cannabis was entered into the United States Pharmacopeia. The use of cannabis in medicine began to decline by the end of the 19th century, due to difficulty in controlling dosages and the rise in popularity of synthetic and opium derived drugs. Cannabis was removed from the U. S. Pharmacopeia in 1941, and officially banned for any use with the passage of the Controlled Substances Act of 1970. In 1996, California became the first U. S. state to legalize medical cannabis in defiance of federal law. In 2001, Canada became the first country to adopt a system regulating the medical use of cannabis.

Countries that have legalized the medical use of cannabis include Argentina, Australia, Brazil, Canada, Chile, Croatia, Cyprus, Czech Republic, Germany, Greece, Israel, Italy, Jamaica, Lebanon, Luxembourg, Malta, Morocco, the Netherlands, North Macedonia, Panama, Peru, Poland, Portugal, Rwanda, Spain, Sri Lanka, Switzerland, Thailand, the United Kingdom, and Uruguay. Countries with the most relaxed policies include Canada, the Netherlands, and Uruguay, In the United States, the legality of medical cannabis varies by state. Cannabis is classified as a Schedule I drug under the Single Convention treaty, meaning that medical use is allowed but that it is considered to be an addictive drug with a serious risk of abuse – along with other drugs such as opium and cocaine. Prior to December 2020 it was also included in Schedule IV, a subset of Schedule I, which is for only the most dangerous drugs such as heroin and fentanyl. Member nations of the UN Commission on Narcotic Drugs voted 27–25 to remove it from Schedule IV on 2 December 2020, following a World Health Organization recommendation for removal in January 2019.

In the United States, the use of cannabis for medical purposes is legal in 38 states, four out of five permanently inhabited U. S. territories, and the District of Columbia. An additional 10 states have more restrictive laws allowing the use of low THC products.

The method of obtaining medical cannabis varies by region and by legislation. In the US, most consumers grow their own or buy it from cannabis dispensaries in states where it is legal. Marijuana vending machines for selling or dispensing cannabis are in use in the United States and are planned to be used in Canada. In 2014, the startup Meadow began offering on demand delivery of medical marijuana in the San Francisco Bay Area, through their mobile app. Almost 70% of medical cannabis is exported from the United Kingdom, according to a 2017 United Nations report, with much of the remaining amount coming from Canada and the Netherlands.

In the United States, health insurance companies may not pay for a medical marijuana prescription as the Food and Drug Administration must approve any substance for medicinal purposes. Before this can happen, the FDA must first permit the study of the medical benefits and drawbacks of the substance, which it has not done since it was placed on Schedule I of the Controlled Substances Act in 1970. Therefore, all expenses incurred fulfilling a medical marijuana prescription will possibly be incurred as out of pocket. However, the New Mexico Court of Appeals has ruled that workers' compensation insurance must pay for prescribed marijuana as part of the state's Medical Cannabis Program.

Medical organizations that have issued statements in support of allowing access to medical cannabis include the American Nurses Association, American Public Health Association, American Medical Student Association, National Multiple Sclerosis Society, Epilepsy Foundation, and Leukemia & Lymphoma Society. Organizations that oppose the legalization of medical cannabis include the American Academy of Pediatrics and American Psychiatric Association. However, the AAP also supports rescheduling for the purpose of facilitating research. and American College of Physicians do not take a position on the legalization of medical cannabis, but have called for the Schedule I classification to be reviewed. The American Academy of Family Physicians and American Society of Addiction Medicine also do not take a position, but do support rescheduling to better facilitate research. The American Heart Association says that "many of the concerning health implications of cannabis include cardiovascular diseases" but that it supports rescheduling to allow "more nuanced marijuana legislation and regulation" and to "reflect the existing science behind cannabis". The American Cancer Society and American Psychological Association have noted the obstacles that exist for conducting research on cannabis, and have called on the federal government to better enable scientific study of the drug. Cancer Research UK say that while cannabis is being studied for therapeutic potential, "claims that there is solid "proof" that cannabis or cannabinoids can cure cancer is highly misleading to patients and their families, and builds a false picture of the state of progress in this area".

In the US, the FDA has approved two oral cannabinoids for use as medicine: dronabinol and nabilone. Nabilone, a synthetic cannabinoid, is also Schedule II, indicating high potential for side effects and addiction. Nabiximols, an oromucosal spray derived from two strains of Cannabis sativa and containing THC and CBD,
| Limited treatment for spasticity and neuropathic pain associated with multiple sclerosis and intractable cancer pain. Relative to inhaled consumption, peak concentration of oral THC is delayed, and it may be difficult to determine optimal dosage because of variability in patient absorption.

A 2022 review concluded that "oral, synthetic cannabis products with high THC to CBD ratios and sublingual, extracted cannabis products with comparable THC to CBD ratios may be associated with short term improvements in chronic pain and increased risk for dizziness and sedation."