Psychopharmacology Flashcards
(36 cards)
What are the principles for prescribing in psychiatry
- Establish a diagnosis
- identify the target symptoms that will be used to monitor therapy response
- Choose a suitable agent and dosage
How do you chose the agent and dose
Select an agent with acceptable side effect profile
Use the lowest acceptable dose.
Keep to simplest regime
Describe the management of psychiatric drugs
Adjust dosage for optimum benefit, safety and compliance
Keep in mind the delayed response for many psych meds and the drug to drug interactions they can have. Delay of 3-6 weeks before maximum dose is in body
If no improvement after 2 months of adequate dose, switch to another antidepressant or use another agent
What are antidepressants used for
Unipolar depression Bipolar depression Organic mood disorders Schizoaffective disorder Anxiety disorders, OCD Panic attacks Social phobia PTSD
What is the best antidepressant
There is no one antidepressant that works better than any other as a first line treatment
Second like there is good evidence for metrazipine
What would influence your decision of what antidepressant to use?
Past history of response
Side effects profile
Other medical conditions
What are the different classes of antidepressants
Tricyclics antidepressants
Monoamine oxidase inhibitors (MAOIs)
Selective Serotonin Reuptake inhibitors (SSRI’s)
Serotonin/noradrenaline reuptake inhibitors (SNRI’s)
Novel antidepressants
Describe the use of tricyclics antidepressants
Very effective but side effects can be strong
Have an effect on seratonin and norepinephrine. Also have antihistaminic, anticholinergic, antiadrenergic affects
Can be lethal to overdose, a one week course can be lethal
Can cause QT lengthening
What are tertiary tricyclics
Have tertiary amine side chains which react with other receptors leading to more side effects
Act predominantly on serotonin receptors
Amitriptyline, Imipramine, dosepin, cloipramine
Contain active metabolites including deipramine and notrptyline
What are the side effects of tertiary TCA
Antihstaminic affects (sedation and weight gain) Anticholinergic affects-dry mouth, dry eyes, constipation memory deficits and potentially delirium) Antiadrenergic affects- orthostatic hypotension, sedation, sexual dysfunction)
What are the secondary trycyclic antidepressants?
Are often metabolites of tertiary amines
Primarily block noreadrenaline
Side affects are the smae but generally less severe
E.g. Desipramine, notriptyline
What do you need to know about tricyclics antidperssants
They exist
What they do
A few names of the most common ones
What are monoamine oxidase inhibitors
Bind irreversibly to monoamine oxidase thereby preventing inactivation of aminesnsuch as norepinephrine, dopamine mad serotonin leading to increased synaptic levels
They are very effective for depression
What are the side effects of monoamine oxidase inhibitors
Orthostatic hypotension weight gain Dry mouth Sedation Sexual Dysfunction Sleep disturbance
What is the cheese reaction
Cheese
Red wine
Processed meats
Beans (not baked?)
Hypertensive crisis caused by MAOI’s taken with tyramine-rich foods or sympathomimetics
How can serotonin syndrome develop in Monoamine oxidase inhibitors
If MAOI’s are taken with medications that increase serotonin or have sympathomimetic actions serotonin syndrome may occur
What is seratonin syndrome?
Abdominal pain Diarrhea Sweats Tachycardia Hypertension Myoclonus Irritability Delirium
to avoid wait two weeks before switching from an SSRI to an MAOI, except fluoxetine where need to wait 5 week due to large half life
What do serotonin reputable inhibitors do?
Block the presynaptic serotonin reuptake
Treat both anxiety and depressive symptoms
Change the receptors in papez circuit (between amygdala and control centres)
What are the side effects of SSRI’s
Activation syndrome (lasts a few days feel on edge, sweaty restless)
Sexual dysfunction, anorgasmia, erectile dysfunction, lack of libido
Can also cause anxiety, restlessness, nervousness, insomnia, fatigue, sedation and dizziness
Very little risk of cardio toxicity in overdose
Discontinuation syndrome (not withdrawal!) agitation, nausea, dysphoria (unsatisfactuon with life) Lasts around a week
Why don’t we use peroxitine much
Short half life causes a lot of starting syndrome and discontinuation syndrome
Can cause a lot of side effects e.g. weight gain anticholinergic affects. Likely to cause discontinuation syndrome
What is the lecturers favourite antidepressant and why?
Setraline- short half life with lower builds up of metabolites (reduces discontinuation syndrome)
Not so good as can cause adverse GI drug reactions
What is another good one?
Fluoxetine (Prozac)
Long half life life stays in the system for 2-3 weeks. If concerned about compliance use this one.
Good way to treat discontinuation syndrome
not good for liver disease
What is citalopram like?
Similar to setraline
Has a dose dependent QT interval side effect. Dose has been lowered to 40mg
may be sedating
What do we not use very often?
Fluvoxamine and escitalopram
