Drugs are generally classified by effect but this is often difficult and results in ambiguity. Many drugs can produce more than one effect, depending on the quantity taken.

1. Behavior stimulants - cocaine caffeine, nicotine.
2. Convulsant - strychnine
3. Narcotic analgesics - opium, morphine, codeine
4. Psychedelics - THC, mescaline, atropine, scopolamine, LSD
5. Antipsychotic agents - resperine
6. Sedatives and hypnotic compounds - alcohol

Most psychoactive compounds contain nitrogen and most are alkaloids. THC, alcohol, LSD and hallucinogenic terpenes are exceptions.

MODE OF ACTION

1. Absorption - orally, injection, membrane absorption.

2. Most act on CNS, drugs reach brain faster than other tissues but passage of chemicals into brain tissue is more difficult than in other parts of body.

3. Alter interactions between neurons. Neurons transmist information chemically via neurotransmitters which can cross the synapse between neurons. Sites in the receptor neuron recognize compound and bind with it, which causes a response in receptor. Psychoactive drugs alter or mimic neurotransmitters: acetylcholine, norepinephrine, serotonin, neuropeptides, dopamine, and anandamine. Check the text for a more detailed description.

DRUG USAGE

1. Drug usage in human cultures is very ancient and was often associated with religious and cultural ceremonies and customs.

2. Reasons for drug usage in modern society are complex and difficult to understand but main difference is that usage is usually not associated with religious and cultural events unless you count rock concerts.

Marijuana

Cannabis sativa - cultivated for 10,000 years, source of fiber, food and oil. One of most widely used nonmedical drugs. May be 2nd most important cash crop in U.S. and #1 in California. Native to central Asia. Indians were first culture to exploit hallucinogenic properties. Discovered that active component is richest in upper leaves and bracts of female plants. Removal of males from population prevents fertilization and seed production which produces sinsemilla - most potent form. Is consumed in milk in India (bhang). Hashish is the resin - very potent.
Smoking of marijuana was introduced by the Dutch. Use of marijuana in Europe was introduced by French artists and writers. Production of Cannabis was introduced in U.S. in 18th century for hemp, use as a drug first occurred in 1800's, first artists, then general use. Federal government used legends of violence associated with marijuana use to help pass 1937 Marijuana Tax Law, which taxed but did not prohibit marijuana. Use in U.S. exploded in 1960's, largely due to Vietnam War.
Medical uses - relief of glaucoma, nausea caused by chemotherapy.
Effects - heavy users suffer lung damage similar to cigarette smokers, general stupidity.

Opium

Papaver somniferum - used for 5000 years. Arabs introduced opium to China in 7th century. Opium addiction became a problem so Chinese officials outlawed it. England traded opium to China for goods even though it was illegal in their own country and in China. China and England fought two wars over the English import of opium, China lost both, ceded Hong Kong to British at end of first war. Use of opium in China did not drop until Communist Revolution in 1949. Most opium is currently grown in SE Asia.

Morphine is purified from opium and is a very potent painkiller. Many Civil War soldiers became addicted to morphine.

Heroin is a derivative of morphine, is even more potent and addicting. Heroin is illegal in U.S., even for medicinal purposes.

Cocaine

Erythroxylum coca - native to Andes, used at least 3000 years, natives of the region chew on leaves to relieve hunger and work at high elevations. Cocaine was isolated in 1860. Freud recommended it as a treatment for alcoholism and morphine addiction. Coca cola contained coca extracts (still does but cocaine has been removed). Many early "remedies" contained caffeine, alcohol and cocaine. Cocaine was declared illegal in U.S. in 1914. Cocaine is expensive and a status symbol - "rich man's drug" and was not widely used until introduction of crack cocaine, which is much cheaper, potent and addictive.

Peyote

Lophophora williamsii - Cactus native to Rio Grande Valley, mescaline is active compound and is present in "buttons" - stem tips. Causes nausea, then hallucinations. Is illegal except for members of the Native American Church.

LSD

Ipomoea tricolor - Morning glory. Seeds contain LSD, very dangerous since seeds are toxic. Synthetic form of LSD is 10X as potent as natural form.

Tropane Alkaloids

Found in members of Solanaceae: Datura, Hyoscyamus, Atropa belladonna, Mandragona officinarum.

Datura - rich in scopolamine, hallucinogenic and very toxic

Atropine - "flying ointment", absorbed through skin, associated with legend of witches flying on broomsticks, werewolf legends.

Tobacco

Solanum nicotianum - stimulant of CNS, addictive, carcinogenic, causes heart and lung disease, miscarriages, infant health disorders.

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