Depression

Question 1

Give examples of SSRI’s and describe the mechanism of action?

Answer 1

SSRI’s: fluoxetine, paroxetine, sertraline

Selective seretonin reuptake inhibitor.

Selectively inhibits the reuptake of 5HT therefore increasing its time at the synaptic cleft.

Note: Symptoms will get worse before they get better

Question 2

Give examples of TCA’s, describe the mechanism of action and the important s/e’s and points to consider when prescribing?

Answer 2

Amitryptaline.

Inhibits the neuronal reuptake of 5HT and NA, therefore longer at the synaptic cleft.

Many TCAs are sedating and dangerous in overdose as they can prolong the QT interval and cause heart block.

Antimuscarinic side effect include:
dry mouth
blurred vision
constipation
urinary retention

Muscarinic receptors are part of the parasympathetic NS so anti muscarinics cause similar s/e to adrenaline

Question 3

Describe the action of MAOI’s and why they are no longer used?

Answer 3

Monoamine oxidase inhibitors.
MAO are an enzyme used in the breakdown of neurotransmitters therefore its inhibition increase neurotransmitter concentrations.

Also inhibits the the breakdown of thiamine, which is found in many foods, because of this it has many interactions with food which can be fatal. The Cheese Reaction. For this reason it is rarely used.

Question 4

Describe the other antidepressants and briefly describe their mechanism of action?

Answer 4

NARI’s: Noradrenaline reuptake inhibitors. Selectively inhibit NA reuptake.
E.g Reboxetine

SNRI’s: Seretonin noradrenaline reuptake inhibitors. Binds to fewer receptors than TCA’s therefore casues fewer s/e’s.
E.g Venlafaxine

NaSSA’s: Noradrenergic and specific serotonergic antidepressants.
Acts as an alpha 2 adrenoreceptor antagonist reducing -ve feedback and therefore increasing the amount of NA and 5HT in transmission.
E.g Mirtazapine

SRM’s: Seretonin receptor modulators
Inhibition of serotonin reuptake and the selective inhibition of postsynaptic serotonin receptors.

Question 5

Describe the pharmaceutical management of a patient with depression?

Answer 5

Moderate depression:
1st line: SSRI
If SSRI fails:

2nd line: alternative SSRI, Mirtazapine, Reboxetine or a TCA if not contraindicated (suicidal intention)

Continue any successful treatment for > 6 months then gradually reduce dose.

Question 6

Describe the different treatments of bipolar affective disorder?

Answer 6

1st line: Lithium as a mood stabiliser (narrow TI)
2nd line: Sodium valporate and carbamezapine to stabilise mood.

Antipsychotics for any delusions particularly in the manic phase: haloperidol, cholpromazine.

Question 7

Describe the medications used to treat anxiety?

Answer 7

Beta Blockers: used to treat the physical symptoms of anxiety such as: palpitations, sweating and tremor.

Benzodiazepines: reduces anxiety and aggression and induces sleep by increasing the activity of GABA (the inhibitory neurotransmitter) in the brain.

Many antidepressants have anxiolytic effects