Marijuana

The Cannabis or hemp plant is very useful. It's fibers can make rope, cloth, and roofing materials, it produces an oil that can be used as a lubricant, and it also produces a psychoactive resin. Galen noted in 200 AD that sometimes giving cannabis to guests helped induce enjoyment and mirth.

Hemp is usually used to describe cannabis plants that are high in fiber whereas marijuana is used to describe those high in psychoactive components.

Sinsemilla is a growing technique that is used to greatly increase potency. In this technique, female plants are separated from male plants before pollination. This makes the female plants produce more resin because they are unpollinated and therefore have no seeds (hence sinsemilla).

Relative to other substances, cannabis is not that addictive or harmful.

Pharmacology

The most potent psychoactive chemical in cannabis is △-9-tetrahydrocannabinol (THC). THC has over 60 metabolites, of which many are active.

THC acts on anandamide receptors, which are located in the limbic system. There are far fewer anandamide receptors in the brainstem so it is very challenging to overdose on marijuana.

Peak intoxication after smoking marijuana usually occurs in 10-30 minutes. THC is highly liquid soluble and tends to accumulate in fat cells.

Tolerance to marijuana develops rather rapidly. THC can persist in the body of a chronic user for up to three months because of slow release from fat stores, although the major effects only last 4-6 hours. In occasional users, urine tests are positive for 1-5 days.

Effects

The most common immediate effect of marijuana is relaxation, along with bloodshot eyes. There can also be increased heart rate and blood pressure as well as decreased intraocular pressure. Marijuana impairs tracking ability and can cause a trailing afterimage of a moving object.

There aren't a lot of long term effects of marijuana, but because THC is a bronchodilator it can expose the lungs to increased irritation. Marijuana over the long term may depress the immune system.

Management

The acute management of marijuana intoxication usually requires no professional attention. It is very rare to see someone in an emergency room who has only smoked pot. There is a chance that patients with severe cardiovascular disease may not tolerate the increased heart rate and blood pressure.