Amphetamines

Question 1

Amphetamines and the 2 deviations?

Answer 1

Synthetic psychostimulants.

• Benzedrine: L-amphetamine.
• Dexedrine: D-amphetamine.

Taken up orally, IV or Subcutaneous injection.

Question 2

Characteristics of methamphetamines and amphetamines?

• Half life?
• where is it metabolized?

Answer 2

• Long half life: 10 hours-longer:
  
  • longer lasting high achieved in comparison to cocaine.
• Metabolized slowly in the liver.

Can experience multiple highs with an injection every 2 hours, for as long as 3-6 days.

Question 3

Mechanism of action of amphetamines and methamphetamines?[2 marks]

Answer 3

Indirect agonists:

• Enter DA nerve terminal via DAT, allows vesicles release DA by binding to VMAT.
• DA is reversibly transported out of cell via DAT.

Overall: high level of DA in the synaptic cleft.

Question 4

Behavioural and neural effects of Amphetamines:

• How it enhances athletic performance?
• Adverse effects?
• Chronic, high dose abuse?

Answer 4

Atheltic performance and its reason for high abuse potential:

• Suppresses appetite and used to treat obesity.
• heightened alertness, increased confidence , sustained physical effort without rest.

Adverse effects:

• leading to dependence and withdrawal syndrome.
  
  • withdrawal may take several weeks to subside.
• Females are more likely to become more dependent.

Chronic high dosage:

• visual and/or auditory hallucinations.
  
  • development of a paranoid state with delusions.

Question 5

Therapeutic uses of Amphetamines?

Answer 5

• Narcolepsy and ADHD:
  
  • within low dosages, produce a calming effect in the PFC.

Question 6

Effects of Amphetamines shown in imaging.

Also the neurotoxicity associated with amphetamines?

Answer 6

PET Scans:

• Reduction in striatal DAT binding in chronic methamphetamine and methcathinone use.

Also damage in the neocortex, hippocampus, and striatum.

Neurotoxicity:

• oxidative stress, excitotoxicity and neuroinflammation.