Depression - Pharmacology Flashcards
Which drugs are usually first line in depression?
SSRIs
How long do anti-depressants usually take to work?
2-6 weeks
If you need a quicker response than what anti-depressants can offer, what treatment can be used?
ECT
How should anti-depressants be started and why?
Started at a low dose and titrated up, to avoid initiation side effects
In psychotic depression an anti-depressant and anti-psychotic can be combined. Which should be the long-term mainstay of treatment?
Anti-depressant
What should you do when prescribing anti-depressants in older people?
Lower the dose - usually half of the adult dose to start with
Why should you be cautious prescribing anti-depressants in younger patients?
They can sometimes cause agitation which leads to suicidal behaviour in young people
What defines non-response to an anti-depressant?
No or inadequate response after 6 weeks at the maximum or highest tolerated dose
Why is it important to check the BNF before changing anti-depressants?
Some drugs require a wash out period
What dose of anti-depressant should patients be continued on once there has been an effect?
The same dose! (the dose that gets you well keeps you well)
After a first depressive episode, how long should treatment with an anti-depressant be continued for?
6-12 months after full resolution of symptoms
After a second depressive episode, how long should treatment with an anti-depressant be continued for?
12-24 months after full resolution of symptoms
After a third depressive episode, how long should treatment with an anti-depressant be continued for?
Indefinitely (if the patient is willing)
When may anti-depressants be continued indefinitely after just one episode?
If the depression has been very severe
How should an anti-depressant be stopped?
By tapering the dose - never stop suddenly
When can an anti-psychotic be used in depression?
It can be combined with an anti-depressant in psychotic unipolar depression, and can also be used as an adjunct to an anti-depressant even if there are no psychotic symptoms
What tests should be checked before starting an atypical anti-psychotic and at 1 month?
BP, weight, lipids, blood glucose, ECG, FBC, Us and Es and LFTs.
After 1 months use of an anti-psychotic, how often should all the relevant tests be performed?
At least yearly, possibly more often depending on the results and other risk factors
In mood disorders, which type of anti-psychotic is more likely to be used?
Atypical
Why can foods containing tyramine not be consumed if on an MAOI?
Tyramine is a potent releaser of noradrenaline, and MAOIs inhibit the breakdown of noradrenaline. This can lead to a hypertensive crisis.
What are some signs which may signal a hypertensive crisis in a patient on an MAOI?
Headache, dyspnoea, nosebleeds, anxiety
What can a hypertensive crisis lead to in a patient on an MAOI?
Arrhythmias, stroke, seizures and death
How is a hypertensive crisis treated?
An infusion of phentolamine
What is an example of an irreversible MAOI?
Phenelzine
What is an example of a reversible MAOI?
Moclobemide
What is the advantage and disadvantage of a reversible MAOI compared to an irreversible one?
Less side effects, but less effective
What is the mechanism of action of MAOIs?
They work by irreversibly or reversibly blocking the monoamine oxidase enzyme to stop the metabolism of monoamine neurotransmitters. This means that the post-synaptic concentration of neurotransmitter is increased and hence the action of the neurotransmitter lasts longer.
The action of which neurotransmitters are increased by MAOIs?
Noradrenaline, dopmine and 5-HT
What are the indications for the use of MAOIs?
Only used in severe, treatment resistant depression
Why are MAOIs not used regularly?
Because of side effects and dietary restrictions, and many other drug interactions
What are the commoner side effects of MAOIs?
Postural hypotension, drowsiness, insomnia, nausea, constipation
What are some rare side effects of MAOIs?
Hypertensive crisis, hepatic impairment, seizures
What other medication should not be taken alongside MAOIs?
Nasal decongestants
What are the dietary requirements when taking MAOIs?
Cheese, wine, yeast products and anything else which is fermented
Why is there sometimes concordance problems with MAOIs?
3 times daily dosing
What are the 3 different types of monoamine reuptake inhibitors?
SSRIs, SNRIs and tricyclics
Name some examples of SSRIs?
Fluoxetine, sertraline, citalopram, escitalopram, paroxetine
What is the mechanism of action of SSRIs?
These selectively block the reuptake of serotonin to increase the amount of neurotransmitter in the synaptic cleft so that the effects of serotonin last longer.
What are the indications for the use of SSRIs?
Usually first line in depression, and also usually first line if an anti-depressant is to be used in bipolar disorder
What are some side effects of SSRIs?
GI upset, nausea, headache, sweats, vivid dreams, agitation, anxiety, insomnia, sexual dysfunction
What electrochemical imbalance may SSRIs cause in older patients?
Hyponatraemia
When should SSRIs be taken and why?
In the morning to try to avoid insomnia
What is the outcome if a patient overdoses on SSRIs?
Relatively safe
What happens if an SSRI is stopped suddenly?
Discontinuation syndrome - can result in shivering, anxiety, dizziness, ‘electric shocks’, headache and nausea
Which SSRI gives the worst discontinuation symptoms and why?
Paroxetine because it has a short half-life
What drug should SSRIs not be taken alongside and why? How can this be avoided?
NSAIDs- increased risk of GI bleed / Give patients a PPI
Which SSRI is safest if there are pre-existent cardiac problems?
Sertraline
Which SSRI is safest in epilepsy?
Citalopram
Why should an ECG always be performed before and after starting an SSRI?
Risk of long QT syndrome which could lead to arrhythmias
Why should SSRI use be restricted in younger people?
Transient increased risk of self-harm and suicide
If an SSRI needs to be used in a younger patient, which is the safest to use?
Fluoxetine
Give two examples of SNRIs?
Venlafaxine, duloxetine
What is the mechanism of action of SNRIs
These selectively block the reuptake of serotonin and noradrenaline to increase the amount of neurotransmitter in the synaptic cleft so that the effects of serotonin and noradrenaline last longer.
Why are SNRIs not usually used first line for depression?
More side effects than SSRIs (but less than tricyclics)
When are SNRIs usually used?
When SSRIs and/or mirtazapine have not worked
What may duloxetine be used for aside from depression?
Neuropathic pain or bladder instability
What are the side effects of SNRIs?
The same as for SSRIs, but also hypertension and arrhythmias
When monotherapy has not worked, venlafaxine works excellently in combination with which other drug?
Mirtazapine (California Rocket Fuel)
When should SNRIs be taken and why?
In the morning to avoid insomnia
Name some examples of tricyclic anti-depressants?
Imipramine, amitriptyline, clomipramine
What is the mechanism of action of tricyclics?
Non-specifically block the reuptake of monoamines in the pre-synaptic terminals to increase the amount of neurotransmitter to make their actions last longer
Tricyclic anti-depressants are equally as effective as SSRIs. Why are they not used first line in depression?
Cardiac side effects and danger in overdose
What are some uses of tricyclics which are not depression?
Neuropathic pain, OCD, anxiety, migraine prophylaxis
The side effects of tricyclics can be put into 3 groups. What are these groups?
Anti-cholinergic, anti-histaminergic and cardiovascular
What are anti-cholinergic side effects seen in tricyclic anti-depressants?
Dry mouth, blurred vision, constipation and urinary retention
What are anti-histaminergic side effects seen in tricyclic anti-depressants?
Sedation and weight gain
What are cardiovascular side effects seen in tricyclic anti-depressants?
Postural hypotension, tachycardia, arrhythmias, cardiotoxic in overdose
What is the remaining side effect of tricyclic anti-depressants which does not come under one of the 3 main groups?
Sexual dysfunction
When should tricyclic anti-depressants be taken and why?
At night due to sedation
Who should tricyclic anti-depressants be avoided in?
Older people, those with pre-existing cardiac conditions and those with suicidal intent
What is the only atypical anti-depressant?
Mirtazapine
What is the name of the drug class in which mirtazapine is found?
Noradrenergic and specific serotonergic antidepressants
What is the mechanism of action of mirtazapine?
Works similarly to an SSRI but also blocks some post-synaptic receptors
Which neurotransmitters are increased by using mirtazapine?
Noradrenaline and 5-HT
When should mirtazapine be used first line?
If the patient has insomnia and/or poor appetite
When is mirtazapine often used?
When SSRIs have not worked
Mirtazapine is also a useful drug for the treatment of which common co-morbidity of depression?
Anxiety
What are the main side effects of mirtazapine?
Sedation, hunger and weight gain, constipation, dizziness and falls, vivid dreams
Mirtazapine can be used in combination with which other drugs?
SSRIs or venlafaxine
What is the advantage of using mirtazapine in combination with SSRIs?
Blocks serotonergic side effects
When should mirtazapine be taken and why?
At night due to sedation
Can mirtazapine be given to people with cardiac problems?
Yes, this is relatively safe
What happens if mirtazapine is taken with alcohol?
Causes GI upset
When do you have to be careful about combining mirtazapine?
If the patient is taking other sedating agents
You should always be aware of drugs causing cognitive impairment in the elderly. Which anti-depressants are most likely to cause this?
Tricyclics
If elderly patients are prone to falls, which type of anti-depressant should you use? What are features which you should try to avoid?
You should stick to SSRIs and try to avoid any drugs which decrease BP or cause sedation
What is probably the best all round SSRI?
Escitalopram
