Psychiatry medications Flashcards
Why can’t SSRI’s and MAOI’s be prescribed together?
Selective seratonin reuptake inhibitors and Monoamine oxidase inhibitors should not be prescribed together as they risk causing seratonin syndrome
What is seratonin syndrome?
It occurs when too much seratonin is in the body.
It is a rare but serious condition.
Causes: tremors diarrhoea jerking of muscles perfuse sweating increased bp and hr mental state changes increased temp seizures/convulsions
What can antidepressants be used to treat?
Depression (uni or bipolar)
Organic mood disorders- mood disorders caused by injury or disease which affects brain issue. Causes can include metabolic (e.g. thyroid) and alcohol
Schizoaffective disorder
Anxiety disorders (including OCD, panic, social phobia, PTSD)
How do antidepressants work?
No really sure although, it thought that they cause increase in levels of neurotransmitter such as seratonin and/or increase the number of receptors for these neurotransmitters.
How do you decide which antidepressant to give?
They all have similar efficacy so is dependant on past repsonse to medication, the potential side effects and coexisting medical condtions.
Usually take 2-4 weeks to improve after reaching theraputic dose (which needs to be done gradually)
What types of antidepressants are avalible?
SSRIs (selective seratonin reuptake inhibitors) - e.g. sertaline, fluoxetine - these are the most commonly used antidepressants now and are usually 1st line as have the best side effect profile and little risk of cardiotoxicity in overdose
SNRIs (seratonin/norephinenphrine reuptake inhibitors)/ dual action antidepressants- similar to SSRI’s but also work on norephinerine as well e.g. venlafaxine, duloxetine
TCAs (tricyclic antidepressants)- very effective but large side effect profile due to affecting many type so receptors, lethal in overdose (1 week supply), QT lengthening e.g. nortriptyline, desipramine
MAOIs (monamine oxidase inhibitors) prevent incativation of amines such as dopamine, sertonin, norepinephrine- very effective in resistant depression e.g. phenelzine sulphate, isocarboxazid
Novel antidepressants- Mirtazapine
Why is sertraline often 1st line?
SSRI’s in general are 1st line because of better side effect profile and low risk of cardiotoxicity in overdose.
Sertraline in particular:
- short half-life (however this means higher risk os discontinuation syndrome if not reduced slowly)
- less sedating than paroxetine ect
- doesn’t really interact with other drugs
cons:
must be taken with food as max absorption requires full stomach and can have GI adverse drug reactions.
Pro’s and con’s of SNRI’s
Pro’s:
- also works on norephinephirne
- can be used in neuropathic pain as well
Con’s
- increase in bp
- significant nausea
- sexual side effects
- QT prolongation
- can cause bad discontinuation syndrome
What is discontinuation syndrome?
Occurs when medication (such as SSRI's and SNRI's) are stopped Agitation Nausea disequilibrium -diziness , vertigo dysphoria- unease, dissatisfaction
What is activation syndrome?
Can occur when patients start taking antidepressants. Is due to increase in seratonin.
Increase anxiety, panic and agitation.
Typically lasts 2-10 days
Can lead to increase in suicidal ideation
Patients should be warned about this and told to get back in touch if symptoms worsen.
MAOIs pro’s and con’s
Pro’s
- very effective in resistent depression
Con’s
- orthostatic hypotension
- weight gain
- dry mouth
- sedation
- sexual dysfunction
- sleep distrubance
- can be hepatoxic
- hypertenisive crisis can occur if taken with tyramine rich foods such as cheese, red wine ect so dietary restriction required
- seratonin syndrome
What is seratonin syndrome?
Very rare
Increased seratonin causes abdominal pain, diarrhea, sweats, tachycardia, myoclonus- twitching muscles, irritabilty, delrium, cardiovascular shock, death
To avoid this leave at least 2 weeks if switching from SSRI to MAOI and 5 weeks if switching from fluoxetine.
Don’t take SSRI and MAOI together.
Mirtazapine pro’s and con’s
Pro’s
- good in substance misuse cases as sedative
- good augmentation for SSRI
Con’s
- increases serum cholesterol
- very sedative
- weight gain
How long should patients be on antidepressants for?
If 1st episode at least 6 months after well again (otherwise 80% relapse compared to 20%)
2nd episode 2 years after recovery
3rd - possibly lifelong
When are mood stablisers used?
Bipolar
Schizoaffective disorder
Cyclothymia
Resistant depression and augementative treatment
