Drugs of abuse: Cocaine and nicotine Flashcards Preview

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Flashcards in Drugs of abuse: Cocaine and nicotine Deck (18)
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1
Q

How is cocaine metabolised?

A

75-90% broken down into inactive metabolites: ecgonine methyl ester and benzoylecgonine.
Half-life = 20-90 minutes.
Plasma/liver cholinesterases.

2
Q

What are the 2 major effects of cocaine on the body?

A

Local anaesthetic- blocks sodium channels at high doses.
Reuptake inhibition at low doses- dopamine, serotonin, noradrenaline are not removed from the synapse- more commonly seen.

3
Q

Does cocaine influence dopamine affinity or efficacy for the dopamine receptor?

A

No- blocks reuptake protein. Affinity and efficacy are related to interactions at the receptor. Number of dopamine molecules in synapse increased, more complexes formed, but same affinity and efficacy.

4
Q

How does cocaine stimulate euphoria?

A

Binds to dopamine transporter in the nucleus accumbens, inhibits reuptake of dopamine from the synapse, causing euphoria. Very direct effect.

5
Q

What are the positive/reinforcing effects of cocaine?

A

Mood amplification- euphoria and dysphoria
Heightened energy
Sleep disturbance, insomnia
Restlessness
Talkativeness
Anger, anorexia, inflated self-esteem, etc.

6
Q

What are the negative/stereotypic effects of cocaine?

A

Tolerance to euphoric effects.
Irritability, hostility, anxiety, fear, withdrawal
Extreme energy or exhaustion
Rambling
Delusions of grandiosity
Total insomnia
Usually associated with chronic cocaine bingeing.

7
Q

What effects does cocaine have on the cardiovascular system?

A

Increases sympathetic output and catecholamines: increased HR, BP and contractility, increased oxygen demand; coronary spasm/vasoconstriction and increased platelet adherence/thrombus leads to decreased oxygen supply. Results in ischaemia, infarction and death.
Decreases sodium transport and has a local anaesthetic effect at high doses: decreased left ventricular function (also due to ischaemia and infarction), combined with arrhythmia, QRS prolongation and QT prolongation leads to death.

8
Q

What effects does cocaine overdose have on the CNS?

A

Seizures
Vasoconstriction
Hyperpyrexia

9
Q

What are nicotine cigarettes made up of?

A

95% volatile: nitrogen, carbon monoxide/dioxide, benzene, hydrogen cyanide.
5% particulate: alkaloids (nicotine itself) dissolved in tar droplets when heated.

10
Q

What are the routes of administration for nicotine?

A

Cigarettes (inhalation)
Nicotine spray
Nicotine gum
Nicotine patch

11
Q

What is the pKa of nicotine?

A

7.9- heavily ionised in acidic cigarette smoke

12
Q

How is nicotine metabolised?

A

In the liver by hepatic CYP2A6 (70-80%), converted to inactive metabolite, cotinine.
Half-life = 1-4 hours.

13
Q

How does nicotine cause euphoria?

A

Stimulates nicotinic acetylcholine receptors in ventral tegmental area leading to dopamine release in nucleus accumbens.

14
Q

What are the cardiovascular effects of nicotine?

A
Autonomic stimulation.
Increased sympathetic stimulation
Increased HR and SV
Vasodilation
Atherogenic effects (poor lipid profile, increased thromboxane, etc.)
Cardiovascular disease
15
Q

How does nicotine affect metabolism?

A

Increases metabolic rate

Decreases appetite

16
Q

How might chronic nicotine affect Parkinson’s disease?

A

Increased brain CYPs which metabolise neurotoxins.

Positive impact.

17
Q

How might chronic nicotine affect Alzheimer’s disease?

A

Decreased beta-amyloid toxicity and amyloid precursor protein.
Positive effect on progression.

18
Q

Can caffeine cause euphoria?

A

Yes- it is a stimulant.

Blocks adenosine receptor and thus increases dopamine release.