Psychiatric Pharmacology Flashcards
What is the rationale behind SSRIs?
Selective Serotonin Reuptake Inhibitors
Deficiency in serotonergic activity in depressed patients
Give three indications for commencing SSRIs
- Mild to Moderate depression where low intensity psychosocial interventions have not helped
- Patients with subthreshold depression
- Mod to Severe depression with concomitant high intensity psychological intervention
Describe the efficacy of SSRIs
Same efficacy as TCAs
Fewer Anti-muscarinic Side Effects
Less Cardiotoxic
What is the SSRI licensed for Major Depression?
Paroxetine
What is the SSRI licensed for Bulimia Nervosa?
Fluoxetine
Name two contraindications to SSRIs
Children (unless seen by psychiatrist)
Mania
Name two instances in which SSRIs should be cautioned
Epilepsy
Suicidal Ideation
Name two DDIs of SSRIs
Some platelet interference
NSAIDs
Warfarin/Heparin
Name three side effects of SSRIs
Decreased alertness
Suicidal feelings
Dyspepsia
Name four causes of Serotonin Syndrome
- Drug is started too high/Dose escalated
- Addition of another serotinergic
- Replacement of antidepressants without long enough clearance period
- SSRI and MAOI
How does Serotonin Syndrome present?
Neuromuscular Hyperactivity
Autonomic Dysfunction (tachycardia, hyperthermia, shivering)
Altered mental state
How is Serotonin Syndrome managed?
Withdrawal of medication
State three pieces of advice that should be given to patients when starting SSRIs
May take a few weeks to work
Must stop if they develop a rash
After remission of symptoms, needs to be continued for another 4-6 months
When should patients on SSRIs be reviewed
After 1-2 weeks of starting
After 4-8 weeks to determine response
What is the first line SSRI for children?
Fluoxetine
What is the first line SSRI for patients post MI?
Sertraline
What is the max dose of Fluoxetine, Sertraline, Citalopram and Paroxetine?
Fluoxetine - 60mg
Sertraline - 200mg
Citalopram - 40mg
Paroxetine - 50mg
How should SSRIs be withdrawn?
Reduce dose gradually over a four week period
Any abrupt stop - Discontinuation Syndrome (restlessness, problems sleeping, sweating)
Which SSRI commonly causes weight gain?
Paroxetine
Give three indications for SNRIs
Major depressive disorder
Anxiety Disorder
OCD
When should SNRIs be taken?
Recommend to take in the morning as can cause insomnia in some patients if taken at night
Name two contraindications to SNRIs
If they have taken MAOI in the past two weeks
NSAIDs
Name three general Side Effects
Loss of Appetite
Increased suicidal thoughts
Sexual Dysfunction (Low libido, anorgasmia)
How should SNRIs be withdrawn?
Slowly taper to avoid discontinuation syndrome
This is common with Venlafaxine due to short half life
Name an indication and contraindication for Venlafaxine as a choice of SNRI
Good for Geriatrics
CI - High Arrhythmic Risk, Uncontrolled Htn
Give an advantage and disadvantage to Duloxetine as a choice of SNRI
Effective for physical depression symptoms
Can’t break capsules due to instability in stomach
Name three populations unsuitable to take Mirtazepine as a choice of SNRI
Elderly
Hypertensive
Urinary retention
Name two SE of Mirtazepine
Weight Gain
Sedative
What is the mechanism of action of TCAs? Give two examples
Blocks Serotonin and Noradrenaline reuptake (first generation as opposed to SNRIs)
Amitryptyline, Imipramine
Name three indications for TCAs
Depression
Anxiety
Chronic Bed Wetting
Describe some interactions of TCAs
CYP450
TCAs can cause weight gain and colnvulsions. Give three other categories of side effects
Antimuscarinic
Antihistaminic
Antiadrenergic
Name two cautions and two contraindications for TCAs
Caution: Epilepsy, Cardiac Disease
Contraindication: Mania, Recent MI
How quickly does a TCA overdose become apparent?
Within the first hour due to easy absorption from small intestine
Name five effects of TCA overdose
Confusion Hypotension Syncope Hypo ventilations Decreased/Absent bowel sounds
How is TCA overdose managed?
IV Sodium Bicarbonate
Name the two types of MAOI
Irreversible - Phenelzine, Isocarboxazid
Reversible - Moclobamide (MAOI- A selective)
Name three indications for MAOI
3rd line for depression
Social Phobia
Panic Disorder
Name some interactions of MAOI
Lethal - SSRIs, TCA
May potentiate cigarette effects
How should MAOI be stopped?
Withdrawn over a four week period with a two week washout
Name three side effects of MAOI
Orthostatic Hypotension
Dry Mouth
Anorgasmia
What is a Hypertensive Crisis with MAOI?
Excess tyramine causes release of Norepinephrine (causing continuous vasoconstriction)
Avoid tyramine rich foods (Alcohol, cheese, fermented foods)
Not required with Moclobamide
When are Antipsychotics required?
Any psychiatric conditions where patient has Delusions and/or Hallucinations
Describe the four dopamine pathways in the CNS
Mesolimbic - too much dopamine in psychosis
Mesocortical - too little dopamine in psychosis
Nigrostriatal - Dopamine dependent movement
Tuberoinfundibular - the pathway that can result in hyperprolactinaemia
What is the MOA of typical antipsychotics?
D2 Receptor Antagonists
Name the three types of typical antipsychotics and give an example of each
High Potency - Haloperidol
Mid Potency - Perphenazine
Low Potency - Chlorpromazine
High potency has much higher risk of Extra Pyramidal SE than Low Potency
Name three side effects of Haloperidol
Akathisia
Parkinsonism
Dystonia
All EPS
Name three contraindications to Haloperidol
Acute stroke
Severe intoxication
Known cardiac disease
How would an overdose of Haloperidol present?
Often just severe forms of the classical side effects
How is a Haloperidol overdose managed?
Activated charcoal if within first hour
Monitor for Long QT
Ropinorole/Bromocriptine for EPS
What should be monitored with Haloperidol?
BMI
BP
Fasting BGC
Name three SE to Chlorpromazine
Dose dependent increase in seizure risk
Weight Gain
Sedation
Name two interactions of Chlorpromazine
Decreased absorption if full stomach/alcohol
Can inhibit own metabolism as it is a CYP2D6 substrate AND inhibitor
What is the MOA of a Atypical Antipsychotics?
Serotonin Dopamine 2 Antagonists
Name three effects more likely with Atypical Antipsychotics (than typical)
Metabolic Syndrome
Weight Gain
T2DM
How long should Atypical Antipsychotics be continued for?
Up to 5 years
If stopping antipsychotics, how long should they be tapered over?
3 months
Describe three side effects of Risperidone
Hyperprolactinaemia
Weight Gain
In doses over 6mg it functions more like a typical - Extrapyramidal
Describe three side effects of Olanzepine
Weight Gain
Hyperprolactinaemia
Hypertriglyceridaemia
How are the effects of Olanzepine monitored?
Fasting BGC at baseline
Then every 4-6 monthly
Then yearly
Depot administration is not an option for Quetiapine. Give three side effects
Weight Gain
Orthostatic Hypotension
Metabolic Syndrome
Name the Atypical Antipsychotic that is NOT KNOWN to cause Metabolic Syndrome
Aripiprazole
Because it’s a partial agonist
Clozapine is an Atypical Antipsychotic with severe SE. When is it used?
Treatment resistant Schizophrenia
Name four SE of Clozapine
Hypersalivation
Incontinence
Increased Seizure Risk
Sedation
How is Clozapine monitored?
Weekly blood draws for 5 months
Fortnightly blood draws for 6 months
Then monthly
Name three general SE for Atypical Antipsychotics
Tardive Dyskinesia (involuntary muscle movement)
Neuroleptic Malignant Syndrome
Extrapyramidal SE
Give three indications for commencing a Mood Stabiliser
Bipolar
Augmenting resistant depression
Schizoaffective
What is the first line mood stabilisers for BPAD?
Lithium
Name five bloods that should be done before commencing Lithium treatment
FBC U&Es TFTs eGFR Pregnancy
How should Lithium therapy be monitored?
- Lithium levels should be checked 12 hours after first dose, and then 3 monthly (therapeutic range is 0.4-1)
- 6 monthly U and Es
- Yearly TFTs
Give three SE of Lithium Therapy
GI distress
Metallic Taste
Fine tremor
Give three contraindications to a Lithium Therapy
Renal Failure
Pregnancy
Breast Feeding
Describe the effects of Lithium Toxicity
Mild (1.5-2) - Ataxia, Dizziness, Coarse Tremor
Severe (>2.5) - Generalised Convulsions, Dysuria, Renal Failure
What could you advise the patient about avoiding Lithium Toxicity?
Stay hydrated
Describe the proposed MOA of Valproate
Inhibits GABA breakdown
Give three indications for use of Valproate
BPAD prophylaxis (Second line) Rapid Cycling (+ Lithium) Mania
What should be measured prior to commencing Valproate?
FBC
LFT
BMI
How should Valproate therapy be monitored?
6 monthly FBC and LFTs
Name three SE of Valproate
Weight Gain
Tremor
Teratogenic
Describe the proposed MOA of Carbamazepine
Blocks voltage gated sodium channels (preventing repetitive firing)
Reduces glutamate release
How is Carbemazepine therapy monitored?
6 monthly FBC and LFTs
Give three SE of Carbemazepine
Rash
Hyponatraemia
Nausea and Vomiting
Describe the proposed MOA of Lamotrigine
Inhibits presynaptic sodium and potassium channels, reducing action potentials
What should be measured before commencing Lamotrigine therapy?
LFTs
FBC
U and Es
How should Lamotrigine therapy be initiated?
Start at 25mg for 2/52
Increase slowly up to 100mg
If stopped for >5d, need to restart at 25mg
Lamotrigine is the drug of choice in child bearing age as it is NOT teratogenic. However, give three other SE
Sedation
Headache
Steven Johnson Syndrome
Name 5 Anxiolytics
Benzodiazepines Pregabalin Buspirone Propranolol Zopiclone
What is the MOA of Benzodiazepines?
GABA Potentiators
Name three SE of Benzodiazepines
Somnolence
Amnesia
Disinhibition
Overdose of Benzodiazpeones causes respiratory depression, what is the antidote?
Flumazenil
Name two short acting and two long acting Benzodiazepines
Short acting - Lorazepam, Midazolam
Long acting - Diazepam, Chlordiazepoxide
What is the MOA of Pregabalin?
Glutamate, Noradrenaline and Substance P inhibitor
Other than being an Anxiolytic, what other actions can Pregabalin have?
Epilepsy control
Pain control
Give three SE of Pregabalin
Headache
Dizziness
Sleepiness
Buspirone is a Non Sedating Anxiolytic. What is it’s MOA?
Serotonin 5HT1A receptor agonist
Give three contraindications to Buspirone
Metabolic Acidosis
MAO Inhibitors
Severely compromised liver/renal function
What can be used as long term management for Anxiety?
SSRI
What is the first line medication for ADHD? What is it’s MOA?
Methylphenidate/Ritalin
Increases dopamine and noradrenaline in synaptic cleft
Give three SE of Ritalin
Difficulty sleeping
Decreased Appetite
Anxiety
When is Ritalin Contraindicated?
MAOI
Tics
Glaucoma
Other than Ritalin, name two other drugs used in ADHD
Amphetamines
Atomoxetine
Give four SE of Amphetamines
Raynaud
ED
Difficulty Urinating
Increased Alertness
What is the MOA of Atomoxetine?
Inhibits Noradrenaline reuptake
Give two contraindications for Atomoxetine
Symptomatic Cardiac Disease
Phaeochromocytoma
What are Hypnotics? How are they different to Sedatives?
Psychoactive drug whose primary function is to increase sleep
Different to sedatives: Sedatives calm or relieve anxiety
Give four examples of Hypnotic Drugs
Barbiturates
Benzodiazepines
Zopiclone
Melatonin
What is the MOA of Zopiclone?
GABA receptor Agonist
Reduces amount of time in REM
Give three SE of Zopiclone
Metallic taste
Nausea
Dizziness
Describe the options for electrode placement in ECT
Bitemporal (4cm above midline between tragus and outer eye)
Bifrontal
Unilateral (both on non dominant hemisphere)
Describe the physical principles of ECT
- Small electrical current passed through the brain of an anaesthetised patient with a muscle relaxant
- Voltage causes neurone firing to be recurrent and synchronous
- Induces neuroplastic changes faster and more powerfully than antidepressants
How often is ECT administered?
Generally 6-12 sessions in total
Roughly two a week
Describe the indication for ECT in terms of depression
Recommended against routine use, but when other treatments have failed
Can use maintenance ECT - patient continues to have ECT at a reduced frequency, alongside meds to maintain remission
Describe the indication for ECT in terms of psychoses
Recommended for a prolonged or severe manic episode
Describe the indication for ECT in terms of catatonia
Recommended as Catatonia is often the final common pathway for severe mental illness
The higher the voltage above the seizure threshold, the more efficacious. Give an example of a drug that increases the seizure threshold, and one that decreases it.
Increased by Anaesthetics
Decreased by Antipsychotics
After a full medical examination, what anaesthetic is used for ECT?
Short acting barbiturate anaesthetics such as Methohexitone Sodium
Give three contraindications to ECT
Status Epilepticus
MI less than 3 months ago
Raised ICP
What is the most common complication of ECT?
Cardiac complications
Bigeminy and SVT
The presence of arrhythmias pre ECT predicts the outcome post ECT
Other than cardiac, give four other potential complications of ECT
Dental Fractures
Aspiration Pneumonitis
Peripheral Nerve Palsies
Anterograde/Retrograde Amnesia
What is Neuroleptic Malignant Syndrome?
Disorder characterised by hyperthermia, muscle rigidity, autonomic dysfunction and depressed/fluctuating levels of arousal over 24-72 hours
Describe the aetiology of Neuroleptic Malignant Syndrome
- Sudden and marked Dopamine receptor blockade India Nigrostriatal/Hypothalamic/Mesocortical and Mesolimbic pathways
- Common with typical antipsychotics such as Haloperidol
- Leads to impaired thermoregulation in hypothalamus and basal ganglia
Give two differentials for Neuroleptic Malignant Syndrome
Phaeochromocytoma
Thyrotoxicosis
Using the mnemonic FEVER, describe the clinical features of Neuroleptic Malignant Syndrome
Fever (higher than 40 degrees Celsius in 40% of patients)
Elevated Enzymes (Creatine Kinase)
Vital Sign Instability (Tachycardia, Elevated/Labile BP, Postural Hypotension)
Encephalopathy
Rigidity
How would you investigate Neuroleptic Malignant Syndrome?
Bloods (Creatine Kinase, FBC, U and Es, Drug Titre)
Urinary Myoglobin
ABG
Name four management options for Neuroleptic Malignant Syndrome
Hydration
Active Cooling
IV Benzodiazepines
Bromocriptine (Dopamine Agonist)
Name three reasons Thiamine is reduced in Wernicke’s Encephalopathy
Inadequate nutritional Thiamine intake
Decreased GI absorption of Thiamine
Impaired Thiamine utilisation in cells
What is the triad of Wernickes Encephalopathy?
Ataxia
Ophthalmoplegia
Confusion
Name five bloods you would do to investigate Wernicke’s Encephalopathy
FBC LFTs Thiamine (Low) Pyruvate (High) ABG
How would you manage Wernicke’s Encephalopathy?
Thiamine (Oral/IV/IM) plus Vitamin B Complex/Multivitamins
When should prophylactic Thiamine be given?
If they are malnourished (50g/day)
If they have decompensated Liver Disease
What is the main complication of Wernicke’s Encephalopathy?
Korsakoff’s Syndrome (Permanent memory features of Confabulation and Amnesia etc)
What is Delirium Tremens?
A disorder of acute alcohol withdrawal
Symptoms normally begin 24-72 hours after cease of Alcohol a Consumption. Give four clinical features of Delirium Tremens
Hallucinations
Confusion
Delusions
Severe Agitation
Give three risk factors which puts a patient more at risk of Delirium Tremens during alcohol withdrawal
Co-Existing medical condition
Older age
Abnormal liver function
Give four managements of Delirium Tremens
A to E
Treat any Hypoglycaemia
Benzodiazepine Sedation
Start Pabrinex (likely to have coexisting Wernicke’s)
What is Acute Dystonia?
Reversible Extrapyramidal effects that can occur after admin of a neuroleptic drug
Describe the aetiology of Acute Dystonia
Drug induced alteration of Dopaminergic/Cholinergic balance in Basal Ganglia
D2 receptor blockade leads to excess cholinergic output
Mental Status and Vital Signs are usually unaffected in Acute Dystonia. Give three clinical features
Oculogyric Crisis (fixed deviation of eyes in one direction)
Protrusion of tongue
Trismus (lock jaw)
Name three potential medications for Acute Dystonia
Anticholinergics - Benztropine
Antihistamine - Diphenhydramine
Benzodiazepines
When does Lithium Toxicity occur?
Safe levels are 0.4-1 mEq/l
Toxicity occurs at >1.5, severe at >2 and >3 is a medical emergency
Give three features of Mild to Moderate Lithium Toxicity
Diarrhoea
Vomiting
Stomach Pain
Give three features of Severe Lithium Toxicity
Seizures
Agitation
Slurred Speech
Describe the three types of Lithium Toxicity
Acute - Too much lithium at once (accidentally or on purpose)
Chronic - Too much lithium daily over a long period of time (affected by dehydration, kidney problems)
Acute on Chronic - Can happen if you take too much for a long time, then suddenly take more
Name three investigations for Lithium Toxicity
ECG
Bloods (U and Es, Glucose)
Lithium levels (Urine or Blood)
How would you treat Mild Lithium Toxicity?
Normally goes away on its own
Drink extra fluids and monitor
How would you treat Moderate to Severe Lithium Toxicity?
If taken in last hour - Gastric Lavage/Activated Charcoal
IV fluids
Haemodialysis
What drug commonly causes Agranulocytosis (<500/cm2)?
Clozapine
What are three granulocytes?
Neutrophils
Eosinophils
Basophils
How should Clozapine induced Agranulocytosis be avoided?
WBC monitoring carried out weekly for the first 18 months
How is Clozapine Induced agranulocytosis managed?
Stop drug and treat and infections
What kind of seizure does ECT induce?
Generalised Tonic Clonic