Drugs of misuse

Question 1

What is the mehanism of action of opioids?

Answer 1

They act on opiate receptors on gaba inhibitory interneurones. This decreses gaba activity and hence causes less inhibition of certain brain neurones.

Question 2

What are the effects of opioids?

Answer 2

• Analgesia
• Respiratory depression
• Pupil constriction
• Reduced gastrointestinal mobility (constipation is a common side effect)
• Euphoria and sedation

Question 3

How do you treat opioid overdose?

Answer 3

With naloxone repeated transfusions as it has a shorter half life than opioids

Question 4

What is the mechanism of action of cocaine?

Answer 4

It works by inhibiting catecholamine reuptake in synapses that causes synaptic concentrations of dopamine and noradrenaline.
It also blocks sodium channels so causes a local anaesthetic effect

Question 5

What are the effects of cocaine toxicity?

Answer 5

Ventricular arrhythmia, coronary artery spasm, severe hypertension
intracerebral haemorrhage, ischaemic stroke

Question 6

How is cocaine overdose managed?

Answer 6

Suportive measures to reverse effects of the drug. Dont use beta blockers for hypertension as this increases the effect of the cocaine on alpha receptors

Question 7

What is the mechanism of action of phenethylamines?

Answer 7

Increase catecholamine release and inhibit neuronal reuptake and MAO activity

Question 8

What is the mechanism of action of hallucigens?

Answer 8

They work by acting as gaba agonists and causing decreased neuronal activity through gaba