Drugs of Abuse

Question 1

What is metabolic tolerance?

Answer 1

Change in the pharmacokinetics = lowered drug CONCENTRATIONS at the active sites.

Because of metabolism: ex = more rapid enzyme degradation of the drug.

Question 2

What is pharmacodynamic tolerance?

Answer 2

Lowered drug RESPONSE at active sites, same amount of drug.

Changes in receptor sensitivity.

Question 3

What is learned tolerance?

Answer 3

Lowered drug effect due to LEARNED compensatory mechanisms.

• -> behavioral tolerance
• -> conditioned tolerance (cues paired with drug admin)

Question 4

What is reverse tolerance?

Answer 4

Sensitization (an INCREASED response) to a drug following repeated doses.

Question 5

What is cross tolerance?

Answer 5

Tolerance develops to one drug, and also then have tolerance to other drugs (often same class or same pharmacodynamic mechanisms)

Question 6

What is cross dependence?

Answer 6

The ability of a drug to suppress the withdrawal of another drug - due to pharmacologically similar effects.

1. morphine + other opioids
2. alcohol, barbs
3. benzos and alcohol

Question 7

What makes a drug more likely to be abused?

Answer 7

1. intense euphoria or relief of a negative effect

2. Enhance dopamine activity in the nucleus accumbens

Question 8

What is heroin, what is its target, mode of action, effect, and risk of addiction?

Answer 8

Heroin:
Opiate
Targets: mu opioid receptor 
Action: agonist
Effect: disinhibition
Risk of addiction: high

Question 9

What are barbituates, what is its target, mode of action, effect, and risk of addiction?

Answer 9

Barbituates:

CNS depression

Question 10

What is diazepam, what is its target, mode of action, effect, and risk of addiction?

Answer 10

Diazepam:
Benzodiazepine, CNS depressant
Targets: GABA channel
Action: Positive modulator (enhances GABA)
Effect: Disinhibition
Risk of addiction: medium

Question 11

What is alprazolam, what is its target, mode of action, effect, and risk of addiction?

Answer 11

Alprazolam:
Benzodiazepine, CNS depressant
Targets: GABA channel
Action: Positive modulator (enhances GABA)
Effect: Disinhibition
Risk of addiction: medium

Question 12

What is amphetamine and methamphetamine, what is its target, mode of action, effect, and risk of addiction?

Answer 12

Amphetamine:
CNS Stimulant
Targets: DAT
Action: Reverse transporter
Effect: DA releaser
Risk of addiction: highest

Question 13

What is cocaine, what is its target, mode of action, effect, and risk of addiction?

Answer 13

Cocaine:
CNS Stimulant
Targets: DAT
Action: inhibitor
Effect: Blocks DA uptake
Risk of addiction: highest

Preferred to smoke.
Onset = 7 seconds!

Question 14

Is N2O a hallucinogen?

Answer 14

Yes! At high enough concentrations.

Question 15

How does onset of effect of a drug affect its risk of addiction?

Answer 15

The faster the onset of effect, the greater the abuse liability.

Therefore, IV and inhalation drugs are more likely to have addictions.

The shorter the half life, the higher the abuse.

• need more frequent administration
• withdrawal is worse for short half lives
  (ex: heroin vs methadone)

Question 16

What is the onset of IV?

What is the onset of mucous membrane?

What is the onset of oral

Answer 16

IV: 15 - 30 seconds

Mucous: 3 - 5 mintes.
–> bypass the liver = more intense and fast than oral

Oral: 20- 30 minutes. Not as much of a rush.

Question 17

Heroin.

What dental drugs could cause additive effect, and what dental drugs will be inhibited?

Answer 17

Heroin:

Acute intoxication:
-Additive = opioid analgesics

Chronic use:
-Inhibited = opioid analgesics (cross tolerance)

Question 18

Ethanol.

What dental drugs could cause additive effect, and what dental drugs will be inhibited?

Answer 18

Ethanol:

Acute intoxication:
-Additive = N2O, benzos, barbs (all depressants)

Chronic use:
-Inhibited = N2O, benzos, barbs (all depressants, cross tolerance)

Question 19

Meth, amphetamine.

What dental drugs could cause additive effect, and what dental drugs will be inhibited?

Answer 19

Meth, amphetamine:

Acute intoxication:
-Additive = Epinephrine

Question 20

How does meth mouth cause xerostomia?

Answer 20

Sympathetic adrenergic actions of drug.

Drug induced cravings for high calorie, sweet, carbonated foods

Dopaminergic actions = cause teeth clenching and grinding

Long action of meth = 12 hours, neglect hygiene.