Pharmacology Flashcards
How long after starting treatment do symptoms of depression begin to improve?
Delay of typically 3-6 weeks before symptoms improve
How long should you wait before switching to a different anti-depressant if no improvement of symptoms?
Trial of 2 months
How long should someone be on anti-depressants after 1 depressive episode?
6 months-year
How long should someone be on anti-depressants after 2 depressive episodes?
2 years
How long should someone be on anti-depressants after 3 despressive episodes?
Lifelong
What is the order of anti-depressant prescribing?
Selective Serotonin Reuptake Inhibitor (SSRI)
Second SSRI or augment with another agent
Serotonin/Noradrenaline Reuptake Inhibitor (SNRI) or novel
Tricyclic Antidepressants (TCAs) or Monoamine Oxidase Inhibitors (MOI), Lithium
Give the classifications of anti-depressants?
Tricyclics (TCAs)
Monoamine Oxidase Inhibitors (MAOIs)
Selective Serotonin Reuptake Inhibitors (SSRIs)
Serotonin/Noradrenaline Reuptake Inhibitors (SNRIs)
Novel antidepressants
Give example of tertiary TCA
Amitriptyline
Imipramine
Doxepin
Clomipramine
Give side effects of TCAs
Antihistaminic
- Sedation
- Weight gain
Anticholinergic
- Dry mouth
- Dry eyes
- Constipation
- Memory deficits
- Potentially delirium
Antiadrenergic
- Orthostatic hypotension
- Sedation
- Sexual dysfunction
- Overflow incontinence
Give example of secondary TCA
Notrtriptyline
Desipramine
Give side effects of MAOIs
Orthostatic hypotension
Weight gain
Dry mouth
Sedation
Sexual dysfunction
sleep disturbance
Hypertensive Crisis/Cheese Reaction
- Can develop when MAOI’s are taken with tyramine-rich foods or sympathomimetics (Cheese, fava beans, wine, processed meat)
How does serotonin syndrome present?
Abdominal pain
Diarrhoea
Sweats/extremes of temperature
Tachycardia
HTN
Irritability
Delirium
Hypertonia
Hyperreflexia
Clonus
Can lead to hyperpyrexia, cardiovascular shock and death
Give example of MAOI
Phenelzine
Rasagiline
Give side effects of SSRIs
GI upset
Sexual dysfunction
Anxiety/restlessness
Insomnia
Sedation/fatigue
Dizziness
Very little risk of cardiotoxicity in overdose
GI bleeding
How does discontinuation syndrome present?
Agitation
Nausea
Sweating
Difficulty sleeping
Diarrhoea
Give examples of SSRIs
Paroxetine
Sertraline
Fluoxetine
Citlopram
Give example of SNRI
Duloxetine
Give pros of Paroxetine
Short half life with no active metabolite meaning no build-up, which is good if hypomania develops
Sedating properties (dose at night) offers good initial relief from anxiety and insomnia
Give pros of Sertraline
Short half life with lower build-up of metabolites
Less sedating when compared to paroxetine
Give pros of Fluoxetine
Long half life so decreased incidence of discontinuation syndromes, good for patients with noncompliance issues
Initially activating so my provide increased energy
Secondary to long half life, can give one 20mg tablet to taper someone off SSRI when trying to prevent SSRI discontinuation
Give example of a novel antidepressant
Buproprion
Mirtazapine
Give side effects of Mirtazapine
Increases serum cholesterol
Sedating/Drowsiness
Weight gain/increased appetite
What is the mechanism of action of Mirtazapine?
Noradrenergic and specific serotonergic antidepressant which increases release of neurotramsitters by blocking alpha2 adrenoreceptors
What is the SSRI of choice in children and adolescents?
Fluoxetine
What is the SSRI of choice post MI or unstable angina?
Sertraline
What is the most common side effect of SSRIs?
GI symptoms
What should be prescribed if a patient is taking an SSRI and NSAID?
PPI for GI protection
Give specific side effects of Citalopram?
QT prolongation
Sedation
What medications can cause adverse drug reactions with SSRIs?
NSAIDS
- Avoid prescribing or give with PPI
Warfarin/Heparin and Aspirin
- Due to increased bleeding risk
- NICE guidelines recommend avoiding SSRIs and considering mirtazapine
Triptans
- Increased risk of serotonin syndrome
MAOIs
- Increased risk of serotonin syndrome
How long should SSRIs be reduced to avoid discontinuation syndrome?
4 weeks
Which SSRI has an increased risk of discontinuation syndrome?
Paroxetine
How do SSRIs affect pregnancy?
During the first trimester gives a small increased risk of congenital heart defects
Third trimester can result in persistent pulmonary hypertension of the newborn
Paroxetine has an increased risk of congenital malformations, particularly in the first trimester
What medication is known to reduce suicide rate?
Lithium
Give side effects of lithium?
GI distress
Thyroid abnormalities
Reduces seizure threshold
Hair loss
Acne
Leukocytosis
Renal failure/oliguria
Weight gain
Metallic taste
Dry mouth
Coarse tremor, fine tremor is seen in therapeutic levels
How does lithium toxicity present?
Coarse tremor, fine tremor is seen in therapeutic levels)
Hyperreflexia
Acute confusion
Polyuria
Seizure
Coma
Ataxia
Blurred vision
Tinnitus
What can precipitate lithium toxicity?
Dehydration
Renal failure
Drugs
- Diuretics, especially thiazides
- ACEI and ARBS
- NSAIDs
- Metronidazole
What monitoring is involved in lithium prescribing?
Baseline U&E and TSH before initiation
Pregnancy test
How does lithium affect pregnancy?
Associated with Epstein’s anomaly in first trimester
When after last dose should lithium levels be checked?
Check 8-12 hours after last dose
Give example of a typical antipsychotic
Haloperidol
Pimozide
Give examples of atypical antipsychotics
Risperidone
Olanzapine
Quetiapine
Clozapine
What is the last resort antipsychotic?
Clozapine
Offered if patient has not responded adequately to at least 2 anti-psychotics
Give side effects of antipsychotics
Neuroleptic Malignant Syndrome (NMS)
Extrapyramidal side effects (EPS)
Metabolic Syndrome
Hyperprolactinaemia
Hypertriglyceridemia
Hypercholesterolemia
What are the extrapyramidal side effects?
Acute dystonia
- Uncontrollable sustained contractions of muscles, such as inability to control gaze (oculogyric crisis)
Parkinsonism
Akathisia
- Restlessness/inability to sit still, such as pacing up and down
Tardive dyskinesia
- Repetitive involuntary movements usually involving the face, such as grimacing, tongue protrusion and lip smacking
How does metabolic syndrome present?
Weight gain
DM, elevated blood sugars
Abnormal LFTs
Dyslipidemia
Give side effects of clozapine specifically?
Agranulocytosis
Myocarditis
Hypersalivation
Weight gain
Sedation
Seizures
Idiopathic hypothermia
Constipation/intestinal obstruction
What do you do if clozapine doses have been missed for more than 48 hours?
Dose needs to be re-started again slowly
What is there an increased risk of when prescribing atypical antipsychotics in the elderly?
Stroke and VTE
What should be considered in psychotic patients with non-compliance?
Once monthly IM antipsychotic depot injection
How should patient’s medication be adjusted before recieving electroconvulsion therapy?
Reduced but not stopped
What can hyperprolactinaemia cause?
Galactorrhea
Menstrual irregularities
Sexual dysfunction
Osteoporosis
Increased risk breast cancer
What side effect does clozapine NOT cause?
Tardive dyskineisa
What birth deformity can valproic acid cause?
Spina bifida
What is used to treat acute dystonia?
Procyclidine (anti muscarinic agent)
What is the mechanism of action of Olanzapine?
Mainly works via blockade of dopamine receptors, but also serotonin receptors
How does neuroleptic malignant syndrome present?
It occurs within hours to days of starting an antipsychotic
Pyrexia
Muscle rigidity
Autonomic lability
- HTN
- Tachycardia
- Tachypnoea
Agitated delirium with confusion
Hyperthermia
Urinary incontinence
What investigations are used in neuroleptic malignant syndrome diagnosis?
>CK
AKI
- Secondary to rhabdomyolysis
>WCC
Deranged LFT
How is neuroleptic malignant syndrome managed?
Stop antipsychotic
IV fluids to prevent renal failure
Dantrolene
Bromocriptine
What antipsychotic should be used in dementia patients?
Typical such as haloperidol
Atypical antipsychotics should be avoided due to increased risk of cerebrovascular events
What is an appropriate therapeutic range for lithium?
0.4-1.0 mmol/l
What is the anti-psychotic of choice in pregnancy?
Olanzapine
How often should lithium levels be monitored?
Initially, check levels at 1 week, once stable monitor at 3 months and TSH/creatinine at 6 months
Which atypical antipsychotic is not associated with weight gain or prolactin elevation?
Aripiprazole
What is the mechanism of action of benzodiazepines?
enhance the effect of GABA, the main inhibitory neurotransmitter
Give side effects of benzodiazepines
Somnolence
Cognitive deficits/memory loss
Disinhibition
Dependence
Respiratory depression
What is used to treat tardive dyskinesia?
Tetrabenazine
What electrolyte abnormality is associated with SSRIs?
Hyponatraemia
What is the difference between typical and atypical antipsychotics?
Typical anti-psychotics are more effective, however atypical have less side effects
What is used to manage the Parkinsonism of extrapyramidal side effects?
Procyclidine
What is the most likely antipsychotic to cause neuroleptic malignant syndrome?
Haloperidol
What can cause a rise in Clozapine levels?
Smoking
What monitoring tests should be done for patients on antipsychotics?
FBC
U&E
LFT
Lipids
Weight
Glucose
Prolactin
BP
ECG