PSYC62H3 Chapter Notes - Chapter 6: Caudate Nucleus, Dopamine Transporter, Aldehyde Dehydrogenase
Chapter 6: Psychostimulants
Psychostimulants: Large Variety of Substances
• Increase psychomotor and sympathetic NS activity
• Improves alertness and positive mood
• Common drugs of abuse but many have therapeutic purposes
o Amphetamines have uses for treatment of ADHD, narcolepsy, and obesity
Psychostimulants: Herbal products, Prescription Drugs, and Substances of Abuse
→ Ephedra
• First amphetamines derived from ephedra
• Extract of Ephedra sinica
• Contains two psychostimulants:
o Ephedrine
o Pseudoephedrine
→ Amphetamines
• All share a similar structure
• Optical isomers: Has a chemical structure that occurs in two different Forms that are
mirror images of e/o → d or l
o Benzedrine = racemic amphetamine → mixture of equal amounts of both d and l
optical isomers
o Dexedrine = d-amphetamine isomer
o Adderall = 3:1 ratio of d-amphetamine and l-amphetamine
• Methamphetamine
o Production of it in a meth lab uses household chemicals along with either
ephedrine or pseudoephedrine
o Meth labs
▪ Produce a crystallized form of methamphetamine → crystal meth
• 1920s → physicians used amphetamine as a drug for raising blood pressure
• 1937 → first used to treat ADHD
• 1919→ Japanese chemist discovered meth
→ Methylphenidate
• Prescription psychostimulant used for treatment of ADHD
• Weaker psychostimulant
→ Cathinones
• Comes from leaves of Catha edulis (aka khat)
• Traditional use involves chewing the leaves or using the leaves in tea
• Fresh khat leaves produce most potent psychostimulant effects
o Limits its use to local inhabitants
→ Cocaine
• Leaves of Erythroxylon coca plant give direct source of cocaine
• Process of separation of cocaine from the leaves:
o Break down and mix coca leaves into a liquid to form a paste → coca paste
o Coca paste is dried and sold for recreational use as is OR transported to a
crystal lab for further processing
• Crystal labs
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o Convert cocaine from a base to salt → becomes powdered form
o Salt form produced for two reasons:
▪ It’s a purer cocaine product thn in base form
▪ Allows for either insufflating (snorting) or intravenously injecting it
o Base form can be smoked (vapour)
• Freebase: transforming salt form into base form
o Aka crack cocaine
• Erythroxylon coca was long sued by indigenous ppl for religious purposes, appetite
suppression, and enhanced stamina
• Cocaine remains classified as a narcotic by the U.S. DEA
Pharmacokinetics of Psychostimulants
→ Route and Forms of Psychostimulant Administration
• Selected route of administration depends on user’s desired purpose for taking the drug
• For therapeutic effects → oral administration
• For rewarding effects → prefer administration routes that provide rapid drug absorption
o intravenous injection
o Insufflation
o Inhalation → heating drug on a foil or plate/glass bulb/pipe
• Peak drug effect onset times for different routes of cocaine in cocaine-addicted indvs
o Inhalation > intravenous > insufflation
o Drug’s onset times can affect its addiction liability
→ Biotransformation of Psychostimulants
• Some psychostimulants produce active metabolites in the liver
o Many times these metabolites exhibit effects similar to parent drug
o Ex: liver enzymes convert methamphetamine(parent drug) to amphetamine
• Drug combos may also interact to produce active metabolites
o Ex: combining cocaine with alcohol produces, through metabolism in liver, an
active metabolite
o Polydrug use: byproduct of combining drugs
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