Psychiatric Drugs Flashcards
What side effects can adrenergic drugs cause?
Sweating, tremor, headaches, nausea, dizziness
What side effect can muscarinic drugs cause?
Dry mouth, difficulty swallowing, thrist, difficulty urinating/urinary retention, hot flushed skin, dry skin
What side effect can drugs acting on histamine receptors cause?
Dry mouth, drowsiness, dizziness, N+V
What are the types of antidepressants?
SSRIs
SNRIs
Tricyclics
MAOIs
Which are the most commonly used antidepressants?
SSRIs
Name some SSRIs
Fluoxetine
Paroxetine
Sertraline
Citalopram
Which is more effective in mild/moderate depression; a TCA or an SSRI?
They are just as effective as each other
Which is more effective in severe depression; a TCA or an SSRI?
A TCA
Can SSRIs be used in under 18s?
Nope, no evidence it works (excpet using fluoxetine with caution)
When should an SSRI be taken, and why?
In the morning as it disrupts sleep pattern if given at night
How do SSRIs work mainly? (MoA)
Reduce neuronal reuptake of serotonin
What other low affinity do SSRIs have?
Muscarinic, histaminergic, and adrenergic receptors
Which is less dangerous in overdose, SSRIs or TCAs?
SSRIs
How do SSRIs work?
Prevent reuptake of serotonin into the presynaptic neurone so more is available. It also causes downregulation of the 5-HT inhibitory receptors.
How well are SSRIs absorbed in the gut?
Well absorbed
What is the half life of SSRIs?
24 hours
How long after an SSRI is started is improvement seen?
2-4 weeks
Can SSRIs be combined with MAOIs? Why?
No!
The combination of multiple drugs that increase serotonin levels can lead to dangerous serotonin levels with adverse effects
Which SSRIs shouldnt be used with TCAs? Why not?
Paroxetine and fluoxetine
Alter hepatic metabolism of TCAs -> toxicity
What side effects can SSRIs cause?
Increased anxiety Emotional numbness Headache Nausea/Vomiting Dry mouth Insomnia Loss of libido Possible increased risk of suicidal/self harm thoughts
What can SSRIs do in epilepsy?
Can prolong a seizure
What can SSRIs do to other drugs?
Alter metabolism of some hepatically metabolised drugs
What can too much serotonin cause (i.e. when ssris are used with maois)?
Tremor
Hyperthermia
CVS S/Es
Can SSRIs be used in bipolar?
Noooooooooooooo
Can SSRIs be addictive?
Probably not, but withdrawal symptoms can occur if they are withdrawn too quickly
Which SSRI is 1st line?
Sertraline
Why is sertraline good?
Safest ssri in CVS disease
What can citalopram cause?
Long QT syndrome
What should be monitored with citalopram and when?
ECG for long QT syndrome before commencing, and after
Which SSRI has the longest half life?
Fluoxetine
What class of drug is clozapine?
An atypical antipsychotic
Which receptors does clozapine act on?
D1, D2, 5-HT, α1 adrenoceptors, and muscarinic receptors
What makes clozapine an atypical antipsychotic?
It acts on serotonin recpetors as well as dopamine receptors
How does clozapine act on serotonin receptors?
As an agonist
How does clozapine act on dopamine receptors?
As an antagonist
What is the indication for cloazpine according to the BNF?
Schizophrenia in patients unresponsive to, or intolerant of, conventional antipsychotic drugs
How many conventional drugs should be trialed before commencing cloazpine?
2 others i.e. clozapine is third line
What other neuro disease can clozapine be used in?
PD with psychosis
What dose should adults aged 18-65 be started on for clozapine?
12.5 mg 1–2 times a day for day 1
How should clozapine be escalated?
After day 1, 25–50 mg for day 2, then increased, if tolerated, in steps of 25–50 mg daily, dose to be increased gradually over 14–21 days, increased to up to 300 mg daily in divided doses, larger dose to be taken at night, up to 200 mg daily may be taken as a single dose at bedtime
How should clozapine be escalated in 18-65 year olds?
After day 1, 25–50 mg for day 2, then increased, if tolerated, in steps of 25–50 mg daily, dose to be increased gradually over 14–21 days, increased to up to 300 mg daily in divided doses, larger dose to be taken at night, up to 200 mg daily may be taken as a single dose at bedtime
How should clozapine be administered in elderly pts?
12.5 mg once daily for day 1, then increased to 25–37.5 mg for day 2, then increased, if tolerated, in steps of up to 25 mg daily, dose to be increased gradually over 14–21 days, increased to up to 300 mg daily in divided doses
What has clozapine been associated with that is important for pt safety? (think GI)
Varying degrees of impairment of intestinal peristalsis
What type of psychoses is clozapine contraindicated in?
Alcoholic and toxic psychoses
What haematological contraindications are there for clozapine?
Hx of agranulocytosis
Hx of neutropenia
What CVS conditions is clozapine contraindicated in?
Hx of circulatory collapse
Any severe cardiac disroders
What CNS disorders is clozapine contraindicated in?
Severe epilepsy
Severe CNS depression
What should be monitored with clozapine, and how regularly?
- FBC (esp for WBCs) every week for 18 weeks, then every 4 weeks after that
- Blood glucose
- Blood lipids and weight
- LFTs
What major side effect is associated with clozapine?
Agranulocytosis
What is the correct way to stop clozapine?
On planned withdrawal reduce dose over 1–2 weeks to avoid risk of rebound psychosis. If abrupt withdrawal necessary observe patient carefully.
What other side effects are experienced with clozapine?
Constipation
Hypersalivation
Weight gain
Sedation
What should happenw ith any antipsychotic before commencing it, especially if there is a history of CVS disease?
A baseline ECG should be done
What is agranulocytosis?
A severe acute lack of white blood cells, usually due to reduced numbers of neutrophils (but can be any class of WBC in severe shortage)
Considering its GI side effects, what should be considered contraindications when starting clozapine?
- Hx of bowel surgery or colonic disease
- Pts receiving drugs that may cause constipation eg anti-muscarinics
What happens in a clozapine overdose?
- Depressed consciousness and respiratory drive (although less than with other sedatives)
- Hypotension, hypothermia, sinus tachycardia and arrhythmias may complicate overdose
Can clozapine be given in hepatic impairment?
No
Can clozapine be given in renal impairment?
Not in severe impairment
Can clozapine cause extrapyramidal S/Es?
Yes if at high doses, but not normally as it is an atypical antipsychotic
Name some commonly prescribed mood stabilisers
Lithium Sodium valproate Carbamezepine Lamotrigine Antipsychotics
How is clozapine metabolised?
By CYP450 in the liver
What is the half life of clozapine?
About 14 hours
What is the indication for Lithium according to the BNF?
Treatment and prophylaxis of 1. mania, 2. bipolar disorder, 3. recurrent depression, and 4. aggressive/self harming behaviour
What is the issue with the different preparations of lithium?
They have different bioavailabilities so changing the preparation requires the same precautions as initiation of treatment.
What precautions should be taken when initiating lithium?
Dose adjusted according to serum-lithium concentration, doses are initially divided throughout the day, but once daily administration is preferred when serum-lithium concentration stabilised.
What are the contraindicatiosn for all Lithium salts?
Addison's disease Heart failure Untreated hypothyroidism Hx/FHx of Brugada syndrome Dehydration or low sodium diets
Why is lithium contraindicated in Addison’s disease?
Lithium inhibits the action of fludrocortisone in the distal kidney tubules (so treatment of addisons becomes ineffective and hypotension can occur)
How does lithium work as a mood stabiliser?
Theory - competition with electrolytes at channels, increases serotonin and decreases 5-HT receptors long term, and possible alteration to neurotransmitter-receptor binding as a second messanger
How is lithium metabolised/excreted?
Excreted by kidneys
Which drugs is lithium not recommended with, considering its excretion?
NSAIDs and ACE-Is
When should bloods be taken to monitor lithium? Why?
12 hours after last dose as it has a narrow therapeutic window
What specific blood checks should be done before commencing lithium? How should they be monitored from then on?
Thyroid function and renal function. Every 6 months after commencing lithium,
Which mood stabiliser has the best evidence?
Lithium
What do 52% of pts on lithium experience?
Memory problems (long term use)
What do 34% of pts on lithium experience?
Tremor
What do 24% of pts on lithium experience?
Drowsiness
How does a lithium overdose manifest?
V&D, coarse tremor, dysarthria, cognitive impairment, restlessness, agitation
How should a lithium overdose be treated?
Increase fluid intake
Anticonvulsants
Supportive measures
Haemodialysis may be necessary
What is the first step on the depression treatment ladder for any level of suspected depression?
Assess, support and advise.
Psychoeducation, active monitoring and further referral.
For persistent subthreshold depressive symptoms, and mild to moderate depression, what is the second step of management?
Low intensity psychosocial interventions
Psychological intervention
Medication
Referral for further assessment.
If second step of management for depressive symptoms doesnt work, what is the next step?
Medication
High intensity psychological interventions
Combined treatment and collaborative care
What is the management for severe and complex depression, risk to life, or severe self-neglect?
Medication, high-intensity psychological interventions, electroconvulsive therapy, crisis service, combined treatments, multiprofessional and inpatient care
In terms of drug choice for depression, how do we choose what to start with?
Discussing treatment options with the patient
After the 1st agent is tried, how do we reassess?
Is the pt happy with the treatment? If so, continue.
If not, try another SSRI or and SNRI.
What do we try if 2 SSRIs have already failed?
An SNRI
What side effects are classic antipsychotics associated with?
Extrapyramidal side-effects
What are the extrapyramidal side-effects?
- Parkinsonism
- Acute dystonia
- Akathisia
- Tardive dyskinease
What is acute dystonia?
Sustained muscle contraction
How can acute dystonia assciated with antipsychotics manifest?
- Torticollis - abnormal head or neck position
- Oculogyric crisis - prolonged upward deviation of eyes.
What is akathisia?
Severe restlessness
What is tardive dyskinesia, and why is it different to other EPSEs?
Late onset choreoathetoid movements like tics, e.g. chewing or pouting of jaw.
Occurs much later onset i.e. with long term antipsychotic use.
How can EPSEs be managed?
If a patient cannot come off antipsychotics, use of procyclidine
