Pharmacology

Question 1

What is the action of cocaine?

What are some desirable/undesirable effects?

Answer 1

Stimulant: Blocks re-uptake of noradrenaline, dopamine and serotonin by blocking Na2+ channels
Feeling of euphoria
Dependence, Psychotic symptoms (anxiety depression), tachycardia, dysrhythmias, HT, convulsions

Question 2

How do local anaesthetics work?
Are they selective?
What are potential bad effects in CNS and CV with too high doses?

Answer 2

Reversibly block conductance of AP’s by blocking Na2+ channels.
Selective to sensory pathways as they are more sensitive to it then motor pathways
Depress cardio and excite CNS

Question 3

What is the mechanism of hydrophobic vs hydrophilic local anaesthetics?
Give examples of each and their method of administrations

Answer 3

Hydrophobic; fast and non use dependent. physically blocks Na channel
Benzocaine; used topically
Hydrophillic; slower and use dependent, binds H+ once crosses membrane and blocks channel thats firing
Lignocaine an aminoamide, can be used topically (skin), injected (dentist) or IV (minor surgery)

Question 4

What are the two possible theories for the action of general anaesthetics?
What are some side effects of general anesthetics?

Answer 4

1. lipid theory; volume expansion of membrane lipids
2. receptor interaction; decreasing excitatory/increasing inhibitory

Depress CV- depress vasomotor centre decrease contractility, arrhythmias, vasodilation
Respiratory- impaired ventilation, airway obstruction, depress of resp centres

Question 5

Out of these general anaesthetics, which do you inhale and which are via IV?

• Desfurane
• Propofol
• Sevoflurane
• Isoflurane
• Thiopentone

Answer 5

Inhalation

• Desflurane
• Sevoflurane
• Isoflurane

IV

• Propofol
• Thiopentone

Question 6

What is the difference between drug dependence and drug abuse?

Answer 6

Dependence; take drugs over other needs

Abuse; illicit drugs or legal drugs illicitly with clinically adverse consequences

Question 7

How does amphetamines work? What are some issues with its use?

Answer 7

Stimulant: Increases NA, Serotonin and dopamine in CNS

Get tolerance and dependence, and can overdose.

Question 8

What dose LSD do?

Answer 8

Psychomimetic; agonist of serotonin receptors

Get hallucinations and sensory confusions etc.

Question 9

What does ecstasy do?

Answer 9

Stimulant AND psychomimetic; releases DA and ST but doesn’t have the strength of effect as the pure stimulants/psychomimetics. Gets feelings of closeness an d love

Question 10

What does cannabis do? Whats the active ingredient?

Answer 10

Depressant; D9-THC which inhibits adenyl cyclase to inhibit GABA neurons so increase the amount of dopamine
Relaxing and feeling of well being, can have sharpened sensory awareness

Question 11

What does alcohol do?

Answer 11

Depressant; increases GABA or decreases glutamate

Get tolerance and dependence

Question 12

How do tricyclic antidepressants work? What are some side effects?

Answer 12

Stop uptake of NA and ST
Side effects
Anticholenergic 
Sedation 
Weight gain 
Postural hypotension

Question 13

How do monoamine oxidase inhibitors work?
Whats an example of a reversible one?
What are some side effects?

Answer 13

Increase ST, NA and DA. Also has a sympathomimetic effect, better in the reversible ones but can still get:
- nausea, dizziness and insomnia
Reversible- Moclobemide

Question 14

How do SSRI’s work?

What are some side effects?

Answer 14

Inhibit re-uptake of serotonin

• suicidal tendencies
• anxiety
• nausea and insomnia
• weight change and decrease libido

Question 15

What drug is used to treat bipolar?

Answer 15

Lithium carbonate

Question 16

What is the effect of phenytoin in epilepsy?

Answer 16

It decreases excitatory input by inhibiting Na channels

Question 17

What are benzodiazepes used in?
What receptor does it interact with?
What are some side effects
How does its action contrast with barbiturates?

Answer 17

Anxiety & sleep disorders (induces sleep)
Can also for Epilepsy (reduces muscle tone) and premedicant (before surgery as obliterates memory)
GABA A an ionotropic receptor mediating fast inhibitory potentials. Its an allosteric modulator; so increasing receptor affinity for GABA
Drowsiness, confusion, impaired coordination. Can also get tolerance and dependence (so therefore withdrawal)

Barbiturates bind the GABA channel and increase duration of it being open- increasing efficacy

Question 18

What drug is given to treat parkinsons? What it given in combo with and why? Whats another adjunct drug?
What are some side effects of levadopa?

Answer 18

Levadopa (L-DOPA) given with a dopa decarboxylase inhibitor as 90% gets broken down in periphery and has side effects
Can also give muscarinic antagonist for tremor
Central side effects; hallucinations and abnormal motor movements.
Peripheral; vomiting, tachycardia, postural hypotension