by Dr. Girivar Singhal
Marijuana is a plant.
The term marijuana refers to all psychoactive substances derived from the dried leaves and flowers of the cannabis plant. Cannabis sativa contains more than 400 compounds in addition to the psychoactive substance, delta-9-tetrahydrocannabinol compound. The high you get from marijuana comes from a chemical called Tetrahydrocannabinol, also known as THC. Some strains contain more or less THC — making them more or less potent. Marijuana cigarettes are prepared from the leaves and flowering tops of the plant, commonly refered to as “buds”, and a typical marijuana cigarette contains 0.5 to 1 g of plant material. Although the usual THC concentration varies between 10 mg and 40 mg, concentrations higher than 100 mg per cigarette have been detected. Marijuana refers to any part of the plant used to induce effects, and hashish is the dried resin from the flower tops.
Cannabis is usually dried and either smoked or eaten, and is widely used. Slang terms for marijuana, include grass, pot, ganja, weed, bud, spliff and reefer, among others. When it is smoked, the onset effect occurs within 10-30 minutes; after ingestion the onset is 1-3 hours. The duration of effect is 4-8 hours. In low doses, cannabis produces euphoria, perceptual alterations and conjunctiva injection, followed by relaxation and drowsiness, hypertension, tachycardia, slurred speech and ataxia. High doses produce acute paranoid pyschosis, anxiety, confusion, hallucinations and distortion of time and space. Most of THC’s effects happen in the brain, where the chemical interacts with receptors on brain cells called cannibinoid receptors. Specific cannabinoid receptors (CB1 and CB2) have been identified in the central nervous system, including the spinal cord, and in the peripheral nervous system. High density of these receptors has been found in cerebral cortex, basal ganglia, and hippocampus. B lymphocytes also appear to have cannabinoid receptors. A naturally occurring THC like ligand has been identified in the nervous system, where it is widely distributed.
THC is quickly absorbed from the lungs into the blood and is then rapidly sequestered in tissues. It is metabolized primarily in the liver, where it is converted to 11-hydroxy –THC, a psychoactive compound, and more than 20 other metabolites. Many THC metabolites are excreted through the feces at a rate of clearance that is relatively slow in comparison to that of most other psychoactive drugs.
Our bodies actually make chemicals very similar to THC, which are used in normal brain function and development. THC co-opts these natural pathways to produce most of its effects. Intravenous misuse of the crude extract of cannabis may cause nausea and vomiting, diarrhea, abdominal pain, fever, hypotension, pulmonary oedema, acute renal failure, disseminated intravascular coagulation and death. Psychological dependency is common but tolerance and withdrawal symptoms are unusual.
Ingestion and smoke of cannabis rarely result in serious poisoning. For patients with drug-induced psychosis reassurance is usually sufficient but i.v. diazepam may be used for sedation. Hypotension usually responds well to intravenous fluids. All patients who have injected cannabis should be admitted, and fluid and electrolyte balance carefully managed, because of the risks of acute renal failure and pulmonary oedema. Chronic marijuana use has also been reported to increase the risk of psychotic symptoms in individuals with a past history of schizophrenia. Persons who initiate marijuana smoking before the age of 17 may subsequently develop severe cognitive and neuropsychological disorders, and may be at higher risk for later polydrug and alcohol abuse problems. Patient with cardiac disease should be strongly advised not to smoke marijuana or use cannabis compounds.
Significant decrements in pulmonary vital capacity have been found in regular daily marijuana smokers. Because marijuana smoking typically involves deep inhalation and prolonged retention of marijuana smoke, marijuana smoke may develop chronic bronchial irritation. Impairment of single-breath carbon monoxide diffusion capacity (DLco) is greater in person who smokes both marijuana and tobacco than in tobacco smokers.
Although marijuana has also been associated with adverse effects on a numbers of other systems, many of these studies replicate and provide confirmation. A reported correlation between chronic marijuana use and decrease testosterone levels in males has been not confirmed. Decrease sperm count and sperm mortality and morphological abnormality of spermatozoa following marijuana use have also been reported. Prospective studies demonstrate a correlation between impaired fetal growth and development and heavy marijuana use during pregnancy. Marijuana has also been implicated in derangement of immune system; in chromosomal abnormalities; and in inhabitation of the DNA, RNA, and protein synthesis; however these findings have not been confirmed or related to any specific physiologic effect in humans.
Dr. Girivar Singhal for The Marijuana Company
In some states, Marijuana use may be illegal. Make sure you abide by all applicable laws, where you reside.