Pharmacology Flashcards
What is the mechanism of action of the monoamine oxidase inhibitors?
Inhibit monoamine oxidase
Monoamine oxidase breaks down serotonin and noradrenaline in the brain - so inhibiting the enzyme inhibits breakdown
What are some of the side effects of the monoamine oxidase inhibitors?
Cheese reaction
Insomnia
Postural hypotension
Peripheral oedema
What is the “cheese reaction”
A side effect of monoamine oxidase inhibitors
Hypertensive crisis caused by inhibition of MAO-A in the gut which prevents the breakdown of dietary tyramine
(tyramine exists in wine and cheese)
Patients need to avoid these foods
With which drug class are patients required to have a restricted diet?
Monoamine oxidase inhibitors
Give some examples of tricyclic antidepressants
Imipramine
Dosulepin
Amitriptyline
Lofepramine
What is the mechanism of action of tricyclic antidepressants?
Block the reuptake of monoamines (noradrenaline and 5-HT) into presynaptic terminals
What are some of the side effects of tricyclic antidepressants?
Anticholinergic effects (blurred vision, dry mouth, constipation, urinary retention)
Antihistaminergic effects
(sedation and weight gain)
Cardiac effects
(postural hypotension, tachycardia)
Fatal arrhythmias with overdose
Give some examples of selective serotonin re-uptake inhibitors (SSRIs)
Fluoxetine
Citalopram
Sertraline
Paroxetine
What is the mechanism of action of the SSRIs?
Selective inhibition of the re-uptake of serotonin (5-HT)
What are some of the side effects of SSRIs?
Nausea Headache Sweating Vivid dreams Worsening of anxiety Sexual dysfunction Hyponatraemia
*relatively safe in overdose compared to the others
With which drug class is there a transient increase in the risk of self-harm in patients <25 years old?
Selective serotonin reuptake inhibitors
*This drug class should be avoided in adolescence
Give some examples of dual reuptake inhibitors (SNRIs)
Venlafaxine
Duloxetine
What is the mechanism of action of the SNRIs?
Block the reuptake of monoamines (noradrenaline and 5-HT) into presynaptic terminals
Which drug class lack major receptor-blocking actions and therefore have fewer side effects than tricyclics?
Dual reuptake inhibitors
Give some examples of atypical antidepressants
Mirtazapine
Bupropion
Give some examples of antidepressants which are noradrenaline selective?
Reboxetine
Desipramine
Protriptyline
Give some examples of antidepressants which are 5-HT selective
Fluoxetine
Citalopram
Sertraline
Paroxetine
What is the gold standard medication for bipolar disorder?
Lithium
What is the mechanism of action of lithium?
Blocks phosphatidylinositol pathway
or
inhibits Glycogen Synthase Kinase 3β
What are some of the side effects of lithium?
Dry mouth/ strange taste Weight gain Sedation Polydipsia/ polyuria Tremor GI upset Ankle swelling
Hypothyroidism
Reduced renal function
What medication should not be taken in combination with lithium?
NSAIDs
Diuretics
ACE. I/ ARBs
Give some examples of anticonvulsants which are used long term as mood stabilisers for bipolar disorder
Valproate, lamotrigine, carbamazepine
Which drug which can be used as a mood stabiliser in bipolar disorder should not be given to women of child bearing age?
Valproate
- teratogenic
Give some examples of antipsychotics which are used long term as mood stabilisers for bipolar disorder
Quetiapine
Aripiprazole
Olanzapine
Lurasidone
What are some side effects of antipsychotics used for bipolar disorder?
Sedation
Weight gain
What is the monoamine hypothesis?
Depression results from a functional deficit of monoamine transmitters - particularly serotonin and noradrenaline
How long should you trial an antidepressant before deciding it isn’t working?
About 2-3 months
What factors may contribute to a patient not responding to medications?
May not be compliant
Dosage too low
Social factors
Might not be the right drug for them
Why do some antidepressants work for some people and not for others?
Everyone has different genetics - one patient may have more of a serotonin problem and the other more a noradrenaline issue
How long should a patient be continued on antidepressants for?
At least 6 months from the resolution of symptoms
NB - what makes you well keeps you well
What are some of the side effects of anticonvulsants which can be used in the management of bipolar disorder?
Sodium valproate is teratogenic
Lamotrigine takes a long time to work and can cause Steven Johnson’s syndrome
Carbamazepine can be quite sedative
What investigations need to be routinely done for patients taking lithium?
Bloods
Lithium levels 12 hours after dose
Thyroid function, parathyroid function and renal function every 6 months
Which antidepressants are the worst in overdose?
Tricyclics are fatal in overdose
SSRIs are not so bad in overdose
Why should tricyclics be avoided in patients with prostatism?
They cause urinary retention (anticholinergic effects)
Which class of antidepressants are useful in patients who are struggling to sleep?
Tricyclic antidepressants - these are sedative
Which drugs are most associated with weight gain?
Mirtazapine, tricyclics, lithium and antipsychotics
Why does lithium require monitoring?
It has a narrow therapeutic index
What drugs are used to treat anxiety disorders?
SSRIs (first line), other antidepressants
Pregabalin (as mono therapy or to augment antidepressants)
B-blockers and benzodiazepines for symptomatic relief
What drugs are used to treat OCD?
SSRIs/ clomipramine - tricyclic
Antipsychotics
What is the mechanism of action of benzodiazepine?
What are the pharmacological effects of this drug class?
Enhance the effect of GABA by allosteric modulation
Relaxation
Anticonvulsant effects
Sedation
What are some of the side effects of benzodiazepines?
Sedation
Psychomotor retardation / impaired coordination
Dependency
Alcohol interaction
Aggression
Anterograde amnesia
Give some examples of benzodiazepines
Diazepam (valium)
Lorazepam
Chlordiazepoxide
Which benzodiazepine is suitable for use in the community?
Diazepam (valium) this is because it has a longer half life than the others
What are some of the clinical uses of benzodiazepines?
Acute treatment of extreme anxiety
Alcohol withdrawal
Mania
Delirium
Status epilepticus
Rapid tranquilisation
What is the mechanism of action of pregabalin, a drug which can be used in the management of anxiety?
Calcium channel blocker and GABA enhancer
*NB only considered if the patient doesn’t respond to other treatments
What specific symptoms are b-blockers useful for?
Physical symptoms such as palpitations and tremors
Give some examples of typical antipsychotics
Chlorpromazine, thioridazine, haloperidol
Give some examples of atypical antipsychotics
Olanzapine, quetiapine, aripiprazole, clozapine
Amisulpramide
What is the mechanism of action of the antipsychotics?
Block dopamine D2 receptors, blocking dopaminergic transmission in the mesolimbic pathways
Which type of antipsychotic are more associated with extra-pyramidal side effects?
Typical antipsychotics
Which typical antipsychotic is associated with being the worst for causing extra- pyramidal side effects?
Haloperidol
What are the 4 main EPSE caused by typical antipsychotics?
Parkinsonism
Acute dystonic reaction
Akathisia
Tardive dyskinesia
How can parkinsonism, an EPSE be managed?
Treatment with anticholinergics
How can acute dystonic reaction, an EPSE be managed?
IV anticholinergics - e.g prochlorperazine
How can akathisia, an EPSE be managed?
Reduce the dose or change to a different drug
When do patients develop tardive dyskinesia, an EPSE?
After long-term use of typical antipsychotics (years)
What is the main side effect of the atypical antipsychotics?
Metabolic syndrome
Both typical and atypicals may cause sedation. T/F?
True
Antipsychotics act by blocking dopamine receptors. what effect does this have on prolactin levels?
How may this present?
Hyperprolactinaemia
Dopamine blocks prolactin production
- therefore drugs which block dopamine block the blockage or prolactin
This may present with gelactorrhea, gynaecomastia and osteoporosis
Antipsychotics cause histamine blockage. How does this present?
Sedation and increased appetite
Antipsychotics cause alpha adrenergic blockage. How does this present?
Dizziness
Postural hypotension
Antipsychotics cause muscarinic blockage. How does this present?
Blurred vision
Dry mouth
Constipation
Urinary retention
Clozapine is the most effective atypical antipsychotic so it is still used despite which serious side effects?
Agranulocytosis
Myocarditis
Also causes metabolic syndrome and hyper salivation
How should patients taking clozapine be monitored?
FBCs weekly for the first 6 months, then very 2 weeks e.t.c
A patient presents with a sore throat. They are known to be taking clozapine, how should they be managed?
STOP CLOZAPINE AND CHECK FBC FOR AGRANULOCYTOSIS
What drugs can make the symptoms of schizophrenia worse?
Drugs which release dopamine into the brain
E.g amphetamines and apomorphine
What is the assumed neurochemical basis of schizophrenia?
Over-activity of dopamine pathways in the brain
Why is haloperidol contraindicated in patients with Parkinson’s?
What medication can be used instead to manage psychosis?
Haloperidol is contraindicated because it can cause EPSE.
Quetiapine can be used instead.
What drugs can be used in the management of Alzheimer’s?
Acetylcholinesterase inhibitors
Memantine
What is the mechanism of action of the acetylcholinesterase inhibitors, which can be used in the management of Alzheimer’s?
Inhibit the re-uptake of acetylcholine, meaning there is more in the synaptic space
(NB the disease is not due to acetylcholine deficiency, but increasing it does help)
Give some examples of acetylcholinesterase inhibitors which can be used in the management of Alzheimer’s disease
Donepezil, rivastigmine, galantamine
What are some of the side effects of the acetylcholinesterase inhibitors which can be used in the management of Alzheimer’s disease?
Bradycardia, muscle cramps, nausea, diarrhoea and headaches
Contraindicated in patients with asthma and COPD
What is the mechanism of action of memantine, a drug which can be used in the management of Alzheimer’s disease?
Antagonist of NMDA receptors which bind glutamate
When can memantine be prescribed?
For patients with moderate Alzheimer’s or patients that can’t tolerate acetylcholinesterase inhibitors
What medications can be used in the management of ADHD?
STIMULANTS
Methylphenidate (ritalin), dexamfetamine and lisdexamfetamine
NON-STIMULANTS
Atomoxetine, antidepressants e.t.c
What is the mechanism of action of methylphenidate (ritalin) which can be used in the management of ADHD?
Improves dopaminergic neurotransmission in networks involved in executive functioning e.g prefrontal cortex
What are some of the possible side effects or methylphenidate (ritalin)?
Appetite and sleep reduction
Dysphoria
Anxiety
Tics
What is the mechanism of action of atomexetine, a medication which can be used in the management of ADHD?
Noradrenergic and dopaminergic agonist
Which anticonvulsants are most useful in patients with bipolar disorder who are primarily manic/ hypomanic vs primarily depressed?
Primarily manic/ hypomanic - sodium valproate
Primarily depressed - lamotrigine
What tests should be done before starting a patient on sodium valproate
LFTs
U&Es
Platelets
What are some of the signs of lithium toxicity?
Blurred vision
Coarse tremor
Ataxia
Drowsiness
If clozapine has been missed for >48 hours, what is the most appropriate management?
Restarted at the starting dose of 12.5mg
What is the role of D1 receptors?
Stimulate cAMP
What is the role of D2 receptors?
Inhibit adenyl cyclase, inhibit Ca2+ channels and open K+ channels
Which EPSE is most associated with dysphonia?
Akathisia
akathisia is the EPSE associated with causing internal restlessness
What are some of the side effects of clozapine?
Weight gain Hyper-salivatino Constipation Seizures Agranulocytosis
Which EPSE are most receptive to treatment with anticholinergics?
Parkinsonism and acute dystonic reaction
Which antipsychotic is most associated with a risk of causing myocarditis and should therefore only be started in hospital?
Clozapine
Which pathways in the brain are responsible for motivation and reward systems?
Mesolimbic and cortical dopamine pathways
How does alpha-adrenergic blockade (S/E of antipsychotics) present?
Dizziness
Lightheadedness
Postural hypotension
Which antipsychotic is most associated with causing metabolic syndrome and should therefore be avoided in people with diabetes?
Olanzapine
Which pathway in the brain is responsible for prolactin release?
Tuberoinfundibular dopamine pathway
Prolonged QT is a side effect more associated with which type of antipsychotics?
Typicals
Which dopamine pathway is responsible for the extra-pyramidal motor system?
Nigrastriatal dopamine pathway
Which receptors do typicals and antitypical antipsychotics mainly block?
Typicals - D2
Atypical - block more 5HT2 (serotonin) than D2 (dopamine)
Why are atypical antipsychotics less likely to cause EPSE than typical antipsychotics?
Atypical antipsychotics block more 5-HT2A (serotonin) than D2 (dopamine) receptors
Which dopamine pathway is responsible for the control of prolactin release?
Tuberoinfundibular dopamine pathway
What is the role of dopamine (D2) receptors in the brain?
Inhibition of adenylyl cyclase
Opening of potassium channels
How are SSRIs eliminated from the body?
Hepatic metabolism
Which class of antidepressants should SSRIs NOT Be given alongside?
MOAIs
Together can cause serotonin syndrome (excess levels of serotonin)
Which class of antidepressants increase bleeding risk and shouldn’t be used in conjunction with aspirin?
SSRIs
*they interact with serotonin receptors on platelets
Why is venlafaxine not used first line?
It has a short half life - can cause serotonin withdrawal syndrome when patients come off it
Which medication that can help with sleep should be avoided in the elderly? What can be used as an alternative?
Zopiclone - *Can cause falls
Melatonin can be used instead
Tricyclics work by increasing the concentration of which neurotransmitters in the synaptic cleft?
Serotonin
Noradrenaline
Dopamine
(they are non-specific)
What are the symptoms of discontinuation syndrome which can occur following withdrawal of an SSRI?
Headache
Sweating and shivering
Increased anxiety
GI symptoms
In elderly patients prone to falls, which antidepressant drug class should you try ad stick to?
SSRIs
- Don’t cause sedation or lower BP
What are some of the symptoms of hypertensive crisis caused by intake of foods containing tyramine in a patient taking an MAOI?
Anxiety
Headache
Dyspnoea
Nosebleeds
SSRIs may cause a transient increase in the risk of self-harm in adolescents, if they have to be used, which one should you choose?
Fluoxetine
Depression causes what to happen to levels of cortisol in the body?
Causes cortisol levels to be chronically increased
Which SSRI is especially associated with prolongation of the QT interval?
Citalopram
Nasal congestants shouldn’t be taken alongside which class of antidepressants?
MOAIs
Which two antidepressants used together are referred to as ‘california rocket fuel’?
Mirtazapine and venlafaxine
Lithium should be avoided in both pregnancy and breastfeeding
True
Which tests should be done every 6 months in a patient taking lithium?
TFTs
Parathyroid function
Renal function
Which tests should be done every 3 months in a patient taking lithium?
Plasma lithium levels
U&Es
Why is it important to test renal function in patients taking lithium?
There is a risk of nephrogenic DI and reduced glomerular function
When a patient is first commenced on lithium, how often should U&Es be formed?
Every 5 days until the therapeutic dose is reached
What tests should be done before starting a patient on sodium valproate?
Platelet count
LFTs
What drug is used to treat benzodiazepine overdose and works as a GABA antagonist?
Flumazenil
Which mood stabiliser drug does EUPD typically respond well to?
Lamotrigine
- Lamotrigine is also used for bipolar II
- Bipolar II and EUPD are often seen as similar as they both involve ups and downs
Why can tricyclic drugs cause fatal arrhythmias?
They affect sodium channels in the heart
What is the role of GABA?
Inhibitory neurotransmitter
Role is for passage of CL- ions into the cell to cause hyper polarisation.
What risk to the baby is there with SSRIs when used in the third trimester of pregnancy?
Risk of PPH of the newborn
What is the big risk of using antipsychotics in the elderly?
Increased risk of stroke and VTE
What is first line for delirium tremens/ alcohol withdrawal?
Oral chlordiazepoxide
SSRIs + NSAIDs (e.g aspirin) increases the risk of GI bleed, what medication should be given to counter this?
PPI
Triptans should be avoided with which antidepressant class?
SSRIs