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Introduction to Pharmacology of Psychoactive Drugs

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1 Introduction to Pharmacology of Psychoactive Drugs
Marijuana Adam Williamson & Jessica Chilcott Introduction to Pharmacology of Psychoactive Drugs

2 Marijuana is a cannabinoid drug.
Cannabinoids are characterized by the chemical compound Tetrahydrocannabinol (THC) and include hashish, hashish oil, and marijuana.

3 History 2737 B.C. Early writings in China note prescribing marijuana to treat every thing from gout to absentmindedness. 1600s American Colonies mandated the growth of Cannabis Sativa for the hemp which was needed for rope and fabric among other things. 1765 George Washington thought to use cannabis for hemp product, medicinal, as well as recreational use. As late as 1850 Cannabis Sativa grown for hemp products as well as for medicinal purposes. Cannabis begins to be prohibited for non-medical use in the U.S.

4 1936 The government released the docudrama “Reefer Madness”
1936 The government released the docudrama “Reefer Madness”. The film has since become a cult classic 1937 Marijuana Tax Act taxed growers, purchasers and, users. While not making marijuana illegal the act made marijuana virtually impossible to obtain. State laws later made marijuana illegal.

5 s During a time of social upheaval marijuana use becomes somewhat more accepted, especially with the large numbers of popular public figures using marijuana 1970 The Controlled Substance Act, reported that marijuana had no potential medicinal use. Determining marijuana’s status as a Schedule 1 Drug.

6 1970 Congress passed the Comprehensive Drug Abuse Prevention and Control Act, which categorized marijuana separately from other drugs and eliminated mandatory Federal sentences for possession of small amounts. 1985 Dronabinol (Marinol), or synthetic THC, classified as a schedule II drug, was approved by the Government for treating nausea and vomiting associated with cancer chemotherapy.

7 1988 DEA administrative law Judge Francis Young finds after thorough hearings that marijuana has clearly established medical use and should be reclassified as a prescriptive drug. The recommendation is turned down. 1996 Arizona and California pass laws allowing marijuana to be prescribed for medicinal purposes. Compassionate Use Act 2001 United States Supreme Court ruled 8-0 against medicinal marijuana under federal law. Despite the fact that 9 States allow medicinal use of marijuana, United States federal law prohibits medicinal use of marijuana.

8 What is Marijuana? Marijuana is the dried mix of flowers and leaves form the female Cannabis Sativa plant. Hashish is the resin, or sap, harvested from the plant. Hashish oil is the essential oil of the female Cannabis Sativa plant.

9 Marijuana: Modes of Absorption
The most common method of absorption is smoking. Either in a loosely rolled cigarette called a joint, or through a pipe or water pipe. However, it can also be cooked in foods or brewed as a tea.

10 Smoking and the Body THC enters the body through the Lungs.
The smoke is inhaled and held in the lungs. Depth of inhalation How long the smoke is held Potency of the marijuana All affect how much THC will enter the plasma

11 THC crosses the blood barrier through the capillaries in the lungs
After inhalation THC can reach the brain in about 14 seconds

12 Effects are felt as the THC begins to bind to the large numbers of natural cannabinoid receptors in the brain. Cannabinoid receptors are found on the presynaptic nerve terminals and inhibit calcium (Ca++) ion flux. As a result glutamate and neurotransmitter release is inhibited.

13 Receptors in the Basil Ganglia and Cerebellum involved with many forms of movement and postural control, are affected by smoking marijuana.

14 In the Cerebral Cortex, cannabinoid receptors are activated which distortions in sense of time, reduces the ability to concentrate and, produces a dream like state. As well as altering how sound and taste are perceived. The Hippocampus which is responsible for movement of short term memories into long term memory storage, is affected. Damaging memory formation capabilities

15 Cannabinoid Receptors

16 Cannabinoid receptors are G-Protein coupled receptors, usually thought to mediate inhibition of adenylyl cyclase, reducing cyclic AMP levels Brain stem structures do not bind with cannabinoids, therefore THC does not affect basal bodily functions such as breathing, explaining the nonlethality of smoking marijuana.

17 Certain Cannabinoid (cannabinoid 2) receptors are found in the lymphatic system. These receptors are thought to produce the immunosuppressive effects of THC. While not dangerous to most individuals, THC can produce increased heart rate and blood pressure. This can be observed when the blood vessels in the eyes dilate.

18 Effects on the respiratory system are the same as smoking cigarettes.
Chronic use of marijuana can reduce testosterone levels in men as well as reducing the production of sperm. In women follicle-stimulating hormone, luteinizing hormone are reduced. The menstrual cycle can also be affected.

19 Smoking Marijuana during pregnancy has many of the same effect as smoking cigarettes, mild fetal growth retardation. There have been cases of infants born with THC dependence and withdrawal.

20 Physical Effects Most of the time, senses may be enhanced and the perception of time is usually altered. Users also report an increased sense of well-being , mild euphoria, relaxation, and relief from anxiety. Contrary to popular belief, illusions and hallucinations occur infrequently.

21 Dependence and Addiction
Dependence is usually classified as: 1. Preoccupation with the acquisition of the drug. 2. Compulsive use of the drug. 3. Relapse to or recurrent use of the drug

22 There is little evidence that marijuana can cause physical dependence
There is little evidence that marijuana can cause physical dependence. However, some individuals experience withdrawal syndrome with symptoms including anxiety sleep disturbances. Withdrawal symptoms usually begin within 48 hours of cessation.

23 There is support for the possibility of psychological dependence occurring.
Psychological dependence is based on maintaining the good feelings associated with smoking marijuana.

24 Tolerance and Withdrawal
Tolerance to the effects of Marijuana can develop especially in long term and chronic marijuana. Tolerance to Marijuana develops from two mechanisms 1. Cannabinoid induced down regulation and gradual desensitizing of brain cannabinoid receptors. 2. Rapid receptor internalization following agonist binding and receptor activation.

25 Treatment Because around 20% of illicit drug users use marijuana in conjunction with other drugs, there is not treatment program specifically for marijuana users. However, treatments such as psychotherapy with an emphasis in behavior modification can be appropriate.

26 Use Rates Marijuana is the number one drug of choice in the United States. An estimated 16 million people regularly smoke marijuana An estimated million people have tried marijuana.

27 As with the use rates for alcohol
As with the use rates for alcohol. Students over estimate peer use rates. Most students believe that their peers are smoking around once a week when in actuality around one third of students use marijuana. Parents on the other hand underestimate use rates. Around 14% of parents believe that their children have tried marijuana, 38% of their children admit to experimenting with marijuana.

28 Medicinal Marijuana The use of marijuana for medicinal proposes dates back more then 5ooo years. However, the debate over medicinal marijuana rages today in the United States

29 Marijuana has been used across cultures for medicinal purposes for over 5,000 years. Renewed interest in the use of marijuana for therapeutic purposes has popped up within the last 15 years.

30 Research on the therapeutic uses of cannabis has been slowed due to the bad reputation marijuana obtained in this country especially in the 1930’s when marijuana was billed as the Assassin of the Youth and was purported to induce a desire to commit violent crimes.

31 There were also concerns, voiced among others, by the first head of the Bureau of Narcotics, Harry Anslinger about the use of marijuana having “sexual connotations” especially on college campuses

32 Between the 1970 Controlled Substance Act and marijuana’s subsequent classification as a Schedule 1 drug reduced the research possibilities for medicinal marijuana. In 1999 the Institute of Medicine determined that cannabinoids have therapeutic value, but that an ingestion route other than smoking should be used.

33 In 1988 Judge Francis Young was quoted as saying : "In strict medical terms marijuana is far safer than many foods we commonly consume. For example, eating 10 raw potatoes can result in a toxic response. By comparison, it is physically impossible to eat enough marijuana to induce death. Marijuana in its natural form is one of the safest therapeutically active substances known to man. By any measure of rational analysis marijuana can be safely used within the supervised routine of medical care.”

34 There has been a lot of concern that legalizing marijuana for medicinal use will undermine drug resistance programs aimed at youth and encourage the push to legalize recreational marijuana use.

35 In 1985 the synthetic THC drug Marinol® was approved to treat nausea and vomiting in Cancer patients. In 1992 Marinol was approved for the treatment of appetite loss and subsequent severe anorexia in AIDS patients.

36 Unauthorized therapeutic benefits of marijuana include:
Reduction of intraocular pressure associated with glaucoma. Use as a bronchodilator in asthmatics. Relief of muscle spasms in such disorders as multiple sclerosis. Preventing seizures associated with epilepsy. Treatment of depression. Treatment of chronic pain, and migraines. Fibromyalgia anxiety depression ,methadone

37 There are those who support the actual smoking of marijuana over the use of Marinol® arguing that smoking marijuana activates more of the receptor sites.

38 However, the ability to regulate dosing is a problem.
In 1960 the average potency of smoked marijuana was around 1-2%, currently the potency average is around 6% which can change the based on quality and grade of the plants. Marinol ® has controlled doses at 2.5, 5, and 10 mg

39 Sociology of Marijuana
While the debate rages over the use of marijuana for medicinal purposes a very active subculture surrounding the recreational use of marijuana has developed.

40 Popular figures in movies, television, and the music industry support the use of marijuana.

41 Or are perceived as supporting marijuana use

42 And of course the internet where you can look up recipes, order seeds, get cultivation advice and paraphernalia.

43 Social Costs Students who smoke marijuana get lower grades in school and are less likely to graduate, that students who do not smoke marijuana. Employees who smoke marijuana have more accidents, increases tardiness rates, more accidents, reduced attentiveness and, a general loss in productivity.

44 Research has shown that marijuana negatively affects driving ability because of altered sense of time and space as well as slowed reaction time. In % of arrests for drug abuse violations were for marijuana. 646,042 people were arrested for possession of marijuana.

45 Compared to Cocaine, Heroin, Methamphetamines, and other drugs
Compared to Cocaine, Heroin, Methamphetamines, and other drugs. Marijuana accounts for an estimated 3.9% of crime. Marijuana accounts for an estimated $10.7 billion (16.3%) in drug related spending each year.

46 Conclusion Marijuana is an intensely popular drug, it is estimated that one third if the population uses marijuana. Marijuana is a controversial drug whose true social cost has not really been measured. Marijuana is also a drug with exceptional medical possibilities, if it can over come its bad reputation.


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