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
What are the options of mood stablisers?
Lithium
Anticonvulsants
Antipsychotics
Describe lithium, pro’s and con’s
Pro’s
Only mediaction to reduce suicide rates in BAD
Con’s
Need baseline U&E’s, TSH and pregnancy test done before use
Must be monitored , after 5 days, then every 3 months once at stable level, then every 6 months because affects renal and thyroid function
GI distress- reduced appetite, vomiting, diarrhoea
Nonsignificant leukocytosis (increase WBC)
polyuria/polydypsia
hairloss
acne
Describe the levels of lithium toxicity
Mild- levels 1.5-2.0 see vomiting, diarrhea, ataxia, dizziness, slurred speech, nystagmus.
Moderate-2.0-2.5 nausea, vomiting, anorexia, blurred vision, clonic limb movements, convulsions, delirium, syncope
Severe- >2.5 generalized convulsions, oliguria and renal failure
How do typical antipsychotics work?
D2 dopamine receptor antagonists
Can be low or high potency. High potency have more risk of extra-pyramidal side effects e.g. parkinsonim symtoms
Examples of high potency - fluphenazine, pimozide
Low potency- chlorpromazine and thioridazine these are more liekly to cause sedation, hypotenison, dry mouth and blurred vision
How do atypical antipsychotics work?
Serotonin-dopamine 2 antagonists (SDAs)
Atypical antipschotics can caue extrapyramidal side effects but they can also caue hyperprolactinemia, weight gain and sedation
Examples
Risperidone- most likely to cause hyperprolactinemia
Olanzapine - LFT’s must be monitored
Quetiapine - can cause hypercholesterolemia and orthostatic hypotension
Aripiprazole - no QT prolongation, low sedation, not associated with weight gain
Clozapine - reserved for reistant patients, can cause agranulocytosis so need regular blood tests (weekly for 6 months, then monthly)- worse side effects
Would want schizophrenic patients to stay on medication as cognitive decline occurs with each episode.
When are benzodiazapienes used and what for?
Only used in short term as dependance can develop. Is reserved for use in emergency sedation and withdrawal states.
Examples of benzodiazapine:
Clonazepam
DIazepam
Flurazepam
Can also be used in insomnia, parainsomnia and anxiety disorders.
Why are anxiolytics not really used anymore?
They work on GABA recpetors so sedate the brain, so are less favourable to use.
What is valproic acid used to treat?
Bipolar disorder Particulalry good in: rapidly cycling patients Co-morbid substance issues Patients with comorbid anxiety disorders
What do you need to check before giveing Valproic acid?
LFTS
FBC
Pregnancy test (should not be given to pregnant women due to neural tube defects)
What are the side effects of valproic acid?
Nausea Vominting Weightgain Sedation Tremor
When is carbamazepine used?
This anticonvulsant is used in the treatment of acute mania and mania prophylaxis
Need to check LFTs and ECG before giving it
What are the side effects of carbamazepeine?
Rash Nausea Vomiting Diarrhoea Sedation Dizziness Aganulocytosis Water retention
