BASIC - PSYCHIATRY Flashcards
Names of SSRIs?
Citalopram, fluoxetine, sertraline, escitalopram
Indications of SSRIs?
- First-line treatment for moderate-to-severe depression and mild depression if psychological treatments fail
- Panic Disorder
- OCD
Mechanisms of SSRIs?
- Inhibit neuronal reuptake of serotonin (5-HT) from the synaptic cleft
- Increase availability for neurotransmission
- SSRIs are preferred - fewer adverse effects and less dangerous in overdose
SE of SSRIs?
- GI upset
- Appetite and weight loss/gain
- Increase risk of bleeding
- Suicidal thoughts and behaviours
o Motivation improves before mood giving period of increased risk. - Hyponatraemia
o esp. older thin females in summer with poor renal function.
o Monitor at risk group
o Can occur with all antidepressants but SSRIs worst, lofepramine/ mirtazapine best. - Lower seizure threshold
- Citalopram/Escitalopram prolong QT interval (if >440ms in men, >470ms in women – prescribe with care/cardiology; >500ms need cardiology input)
What is serotonin syndrome?
Causes, symptoms/signs, investigations, Rx?
o Excess serotonin (via e.g. SSRI + TCA/MAOI/St John’s Wort/Ecstasy)
o Causes – therapeutic drugs, OD, interactions, cocaine/MDMA
o Triad of autonomic hyperactivity, neuromuscular abnormality and altered mental state
o Sx: Usually within 6 hours - restless, fever, tremor, myoclonus, confusion, fits, arrhythmias
o Ix – Bloods (FBC, U&Es, CK, LFTs), urine drug screen
o Supportive treatment (IV fluids may be needed)/monitoring, stop drug
o Activated charcoal if recent OD
o Most mild and better within 24hrs
What happens in sudden withdrawal of SSRIs?
Sudden withdrawal can cause GI upset, flu-like symptoms, sleep disturbances
Cautions of SSRIs?
o Epilepsy
o Peptic Ulcer disease
o Metabolised by liver – reduced dose in hepatic impairment
o Aspirin and NSAIDs – need gastroprotection
Contraindications of SSRIs?
o Do not give with MAOIs (Serotonin syndrome)
o Avoid drugs which prolong QT (antipsychotics)
o Mania
Prescription of SSRIs?
- Oral
- Started at low dose, taken regularly and increased according to response
- Improve symptoms over a few weeks, particularly sleep and appetite
How long should you continue SSRIs?
- Should continue SSRIs for 6 months after they feel better to prevent relapse (2 years for recurrent)
- Do not stop treatment suddenly
Monitoring of SSRIs?
- Review 1-2 weeks after starting and regularly after that
- If no effect after 4 weeks, change dose or drug – normally adjust dose after 6-8 weeks
Treatment of overdose of SSRIs?
- Activated charcoal within 1 hour of the overdose reduces drug absorption
Names of TCAs?
Amitriptyline, Lofepramine, imipiramine
Indications of TCAs?
- Second line for moderate-to-severe depression where first-line serotonin-specific reuptake inhibitors (SSRIs) are ineffective
- Neuropathic pain
Mechanism of TCAs?
- Inhibit neuronal reuptake of serotonin (5-HT) and noradrenaline from the synaptic cleft
- Increase availability for neurotransmission
- Block muscarinic, histamine (H1), α-adrenergic (α1 and α2) and dopamine (D2) receptors – adverse effects
SE of TCAs?
- Blockage of antimuscarinic receptors
o Dry mouth, constipation, urinary retention, blurred mouth - Blockage of H1 and a1 receptors
o Sedation, hypotension - Blockage of dopamine receptors
o Breast changes, sexual dysfunction, extrapyramidal symptoms (tremor, dyskinesia) - Arrhythmias, prolongation of QT and QRS complexes
Overdose of TCAs?
o Severe hypotension, arrhythmias, convulsions, coma and can be fatal
Sudden withdrawal of TCAs?
o Cause GI upset, flu-like symptoms, sleep disturbances
Caution of TCAs?
- Elderly
- CVD
- Epilepsy
- Constipation, BPH or raised intraocular pressure
Contraindications of TCAs?
- MAOIs
- Augment antimuscarinic effects of other drugs
Prescription of TCAs?
- Similar efficacy but more adverse effects and dangerous in overdose
- Oral tablets
- Supply small quantity of medication at a time when overdose risk (2 weeks)
- Symptoms improve over few weeks, particularly sleep and appetite
How long should TCA treatment last?
- Drug treatment should carry on 6 months following symptom resolution to prevent relapse (2 years in recurrent)
- Dose reduction slowly over 4 weeks when discontinuing
Monitoring of TCAs?
- Review symptoms after 1-2 weeks and then regularly
- If no effect after 4 weeks, change dose or drug – normally adjust dose after 6-8 weeks
Treatment of TCA overdose?
- Activated charcoal within 1 hour of the overdose reduces drug absorption
- IV lorazepam or IV diazepam (emulsion form) to treat convulsions
Names of SNRIs?
- Venlafaxine, duloxetine
Indications of SNRIs?
- Option for major depression when first-line SSRIs not tolerated
- GAD
Mechanisms of SNRIs?
- Serotonin and noradrenaline reuptake inhibitor in synaptic cleft
- Increase availability of monoamines
- Weaker antagonist of muscarinic and histamine (h1) receptors than TCAs – less side effects
SE of SNRIs?
- Dry mouth, diarrhoea, constipation, nausea
- Headache, insomnia, abnormal dreams and confusion
- Hyponatraemia
- Serotonin syndrome
- Suicidal thoughts and behaviours
- Prolong QT interval
Sudden withdrawal of SNRIs?
o GI upset, flu-like symptoms, sleep problems (more than other ADs)
Cautions of SNRIs?
o Elderly
o Dose reduction in hepatic and renal impairment
o CVD as increased risk of arrhythmias
Prescription of SNRIs?
- Oral tablet
- Low dose then titrated up according to response
- Should improve symptoms over few weeks, particularly sleep and appetite
How long should drug treatment of SNRIs last?
- Drug treatment should carry on 6 months following symptom resolution to prevent relapse (2 years in recurrent)
- Dose reduction slowly over 4 weeks when discontinuing
Monitoring of SNRIs?
- Review symptoms after 1-2 weeks and then regularly
- If no effect after 4 weeks, change dose or drug – normally adjust dose after 6-8 weeks
Name of NaSSa?
Mirtazapine
Indications of mirtazapine?
- Option for major depression where first-line SSRIs fail to work
Mechanism of mirtazapine?
- Antagonist of inhibitory pre-synaptic Alpha-2-adrenoreceptors
- Potent antagonist of histamine (H1) but not to muscarinic receptors – less side effects
- Increases availability of monoamines
SE of mirtazapine?
- Sedative
o Sedative effects more potent at lower doses
o Low doses, antihistamine effects predominate
o Higher doses augmented monoamine transmission counter-acts - GI upset
- Weight gain
- Headaches, confusion, abnormal dreams
- Hyponatraemia – least in mirtazapine
- Serotonin syndrome
- Suicidal thoughts and behaviours
Withdrawal symptoms of mirtazapine?
o GI upset, flu-like
Caution of mirtazapine?
o Elderly
o Dose reduction in hepatic and renal impairment
Prescription of mirtazapine?
- Oral tablet
- Low dose then titrated up according to response
- Should improve symptoms over few weeks, particularly sleep and appetite
- Mirtazapine taken at night for best sedative effects
Length of treatment of mirtazapine?
- Drug treatment should carry on 6 months following symptom resolution to prevent relapse (2 years in recurrent)
- Dose reduction slowly over 4 weeks when discontinuing
Monitoring of mirtazapine?
- Review symptoms after 1-2 weeks and then regularly
- If no effect after 4 weeks, change dose or drug – normally adjust dose after 6-8 weeks
Name of MAOIs?
- Phenelzine, Moclobemide (Reversible inhibitor – RIMA)
Indications of MAOIs?
- Option in Major depression when first-line SSRIs fail
Mechanism of MAOIs?What foods should be avoided and why?
- Inhibit monoamine oxidase (MAO-A & MAO-B)
- Increase availability of monoamines
- Monoamine oxidase breaks down tyramine in your gut
o If you eat tyramine containing food: cheese, red wine, bovril there is potential for hypertensive crisis
SE of MAOIs?
- Dizziness, postural hypotension
- Hypertensive crisis
- Serotonin syndrome
- Withdrawal symptoms
Cautions of MAOIs?
o Blood disorders
o CVD
o ECT therapy
o Elderly, epilepsy
Contraindications of MAOIs?
o Stroke
o Mania
o Pheochromocytoma
o Hepatic impairment
Monitoring in MAOIs?
- Monitor BP
- Review symptoms after 1-2 weeks and then regularly
- If no effect after 4 weeks, change dose or drug – normally adjust dose after 6-8 weeks
Prescription of MAOIs?
- Oral tablet
- Low dose then titrated up according to response
- Should improve symptoms over few weeks, particularly sleep and appetite
Avoid what foods when on treatment of MAOIs?
- Avoid food that is stale, avoid game, avoid alcoholic/de-alcoholised drinks - interaction for up to 2 weeks after treatment cessation
Length of treatment of MAOIs?
- Drug treatment should carry on 6 months following symptom resolution to prevent relapse (2 years in recurrent)
- Dose reduction slowly over 4 weeks when discontinuing
Name of benzodiazepines?
Diazepam, Temazepam, Lorazepam, Chlordiazepoxide, Midazolam
Indications of benzodiazepines?
1st line – Seizures, status epilepticus - Long-acting lorazepam/diazepam 1st line – alcohol withdrawal - Oral long-acting chlordiazepoxide Sedation for interventional procedures - Short-acting midazolam Short-term treatment of severe anxiety, insomnia - Intermediate-acting temazepam given at bedtime
Mechanisms of benzodiazepines?
- γ-aminobutyric acid type A (GABAA) receptor is a chloride channel
- Opens in response to GABA, making the cell more resistant to depolarisation, the main inhibitory neurotransmitter in the brain
- Benzodiazepines facilitate and enhance binding of GABA to the GABAA receptor
- Depressant effect on synaptic transmission
SE of benzodiazepines?
- Dose-dependent drowsiness, sedation and coma
- Relatively little cardiorespiratory depression in benzodiazepine overdose
- Loss of airway reflexes can lead to airway obstruction and death
Withdrawal symptoms of benzodiazepines?
- Withdrawal symptoms
o Anxiety, insomnia, tremor, agitation, nausea, sweating, seizures, delirium
What happens if you use benzos regularly?
- If used regularly, tolerance and dependence develop
Interactions of benzodiazepines?
- Additive to sedating drugs (alcohol, opioids)
- Depend on CYP450 enzymes for elimination – effects increased/decreased with inducers/inhibitors
Cautions of benzodiazepines?
o Elderly more susceptible to effects (lower dose)
o Avoid in respiratory impairment, neuromuscular disease (myasthenia gravis), liver failure (lorazepam if needed)
Prescription of benzodiazepines?
- Water-based solution or oil in water emulsion
- Solution more irritant to veins
- Therapy only short-term for anxiety or insomnia
o Risk of dependence (<4 weeks) - Do not drive or operate heavy machinery after taking drug
- Sedation may persist for a few days
Treatment of overdose of benzodiazepines?
- Activated charcoal can be given within 1 hour of ingesting a significant quantity of benzodiazepine