Flashcards in Pharmacological Therapy Deck (74)
What are the TCAs?
Amitriptyline - most tox, sed
Imipramine - less sed
Lofepramine - least tox in OD, less sed
Clomipramine - sed
Dosulepin - most tox, sed
Trazodone - sed
Selective serotonin and noradrenaline reuptake inhibitor
What are Mirtazapine's SEs?
Increased appetite/weight gain
What are the SSRIs?
What are the atypical antipsychotics?
Dopamine D2 receptor blockade
Olanzapine +ve sx
Aripiprazole red EPSE
What are the typical antipsychotics?
Dopamine D2 receptor blockade
Flupentixol decanoate - depot assoc with v severe EPSEs
Tend to cause distressing EPSEs at normal treatment doses
What are SEs of typical antipsychotics?
EPSE: extra pyramidal side effects
Weight gain, dyslipidaemia + increased risk diabetes
Neuroleptic malignant syndrome
Most common side effect= hypersalivation
1-2% Agranulocytosis rate
Increased prolactin levels
What are the benzodiazepines?
Incr Cl channel freq = enhance GABA
What are the MAOIs?
Irreversible MAO inhibition
Moclobemide: reversible inhibition
How would you counsel patients regarding SSRIs?
Avoid drinking alcohol whilst in antidepressants due to increased sedation
Never drive if feeling drowsy on antidepressants
Onset of action is delayed
Outline side effects
What are common side effects of SSRIs?
Appetite, weight change
Anxiety + agitation
Insomnia, tremor, dizziness
What are common side effects for SSNRIs
Same as SSRIs plus
Noradrenergic and Specific Serotonin Antidepressant
What are the SEs of TCAs?
Dry mouth, blurred vision,
Constipation, urinary retention
Nausea, weight gain
What are the common side effects of MAOIs?
Hypertensive crisis "cheese reaction"
Postural hypotension, dizziness
Headache, blurred vision
What are the side effects of St John's Wort?
As effective as TCAs for mild-mod depression
Induces P52 risks drug interactions: reduces warfarin, ciclosporin, COCP
What are discontinuation symptoms?
Occur when antidepressant stopped suddenly:
Flu like sx, electric shock sensations, headaches, vertigo, irritability
To avoid withdraw over a few weeks
What should you be careful of when swapping antidepressants?
If of different classes they might interact dangerously: check!
SSRI-> TCA: cross-taper
Drug free washout period: fluoxetine 1 wk
Start venlafaxine v slowly 37.5mg each day
What is serotonin syndrome?
Sx: restlessness, sweating, myoclonus, confusion, fits
Acts on 5HT1a receptor
No antidepressant action alone
May synergistic effect in combination with SSRIs
What are the mood stabilisers?
?action on Na channels / GABA
Unknown mech of action ? cAMP inhibition
Therapeutic range: 0.6-1mmol/L
>1.2 mmol/L = toxic
Monitored weekly after start/ dose change until a steady therapeutic level achieved
U+Es & TFTs every 3-6 months
Can cause renal impairment + hypothyroidism
Active drug= valproic acid
Plasma levels don't require monitoring
Dose related toxicity not an issue
2nd line, less effective than lithium
Can cause toxicity at high doses
Induces liver enzymes
Levels must be carefully monitored
Nausea + vomiting
Nausea, vomiting, diarrhoea
Oedema, weight gain, hyponatraenia
Presents: GI disturbance, sluggishness, giddiness, ataxia, gross tremor, fits, renal failure
Triggers: salt balance changes, drugs affecting lithium excretion (NSAIDs, diuretics, ACEi), OD
Management: stop lithium, medics: rehydration, osmotic diuresis
Mood stabilisers and pregnancy, what are the risks and how are they mitigated?
Lithium: Ebstein's anomaly
Valproate + Carbamazepine: spina bifida
Teratogenic risk must be weighed against harm of a manic relapse!
Women of childbearing age: contraceptive advice + folate supplement
If medications are used during pregnancy close monitoring of fetus req
What are the EPSEs associated with antipsychotics?
Dystonia: involuntary painful sustained muscle spasm - within hours - torticolis, oculogyric spasms
Akathisia: unpleasant feeling of restlessness -> pacing/jiggling - hours to weeks
Parkinsonism: resting tremor, rigidity, bradykinesia - days to weeks
Tardive dyskinesia: rhythmic involuntary movements, often grimacing, sucking or chewing movements - months to years
How are EPSEs of antipsychotics treated?
Dystonia = anticholinergics e.g. Procyclidine
Akathisia = decr dose/change antipsychotic, add propanolol or benzos
Parkinsonism = decr dose/change antipsychotic, anticholinergic
Tardive dyskinesia (oft irreversible) = stop antipsychotic/decr dose avoid anticholinergics, switch to atypical / clozapine
What factors are associated with increased risk of violence in schizophrenics?
Past Hx violence
Acute psychotic symptoms
Non-concordance with treatment
Access to weapons
Specific threats to a victim
Comorbid personality disorder
What risk is a schizophrenic to themself?
Lifetime suicide risk= 10%
Risk highest in early years after diagnosis, following 1st admission or where there are depressive symptoms
What is the prognosis in schizophrenia?
25% experience no further issues after one episode
66% remain liable to relapse
10% seriously and continuously disabled
What SSRI is preferred post MI?
What SSRI is preferred in children + young adults?
Which SSRI should be avoided in those with known long QT or taking other drugs which could prolong QT
Also assoc with sexual dysfunction
If prescribing SSRI to a patient on NSAIDs what must you also prescribe?
If prescribing SSRIs what might give you cause to reconsider?
Warfarin/heparin - avoid SSRIs -> mirtazapine
NSAIDS - avoid/ coprescribe PPI!
Triptans - avoid SSRIs
Renal impairment -> incr risk SIADH: monitor renal function + U + Es
When should SSRI use be reviewed?
How do you avoid discontinuation symptoms following SSRI use?
Gradually reduce dose over 4 wks when stopping
Except fluoxetine which can be stopped straight away
Incr risk of sx with paroxetine
What are the discontinuation sx seen following abrupt end to SSRI use?
When would clozapine be offered?
With treatment resistant schizophrenia
2 other antipsychotics, one being an atypical
Which were trialled for 6-8 wks without effect
What increased risks are associated with antipsychotic use on the elderly?
Incr stroke risk
Incr VTE risk
What are the non EPSEs of antipsychotics?
Anti muscarinic sx
Incr prolactin: galactorrhoea, red glucose tolerance
Neuroleptic malignant syndrome: pyrexia muscle stiffness
Red seizure threshold
Causes of long QT syndrome
How do you treat TCA overdoses presenting with widened QRS complexes
How do you treat lithium OD?
Mild/mod: fluid resus with IV normal saline
How do you treat benzo OD?
How do you treat opiate OD?
How do you treat paracetamol OD?
How do you treat salicylate OD
(Urine alkalinisation if mild but CI in cerebral + pulm oedema
How do you treat warfarin OD?
How do you treat heparin OD?
How do you treat beta blocker OD?
If bradycardic give atropine
If resistant give glucagon
How do you treat ethylene glycol OD?
How do you treat methanol poisoning
Fomepizole or ethanol
How do you treat organophosphate poisoning?
How do you treat digoxin OD
Digoxin specific antibody fragments
How do you treat iron overload?
How do you treat lead poisoning?
How do you treat cyanide poisoning?
Amylnitrite, sodium nitrite + sodium thiosulphate
What is neuroleptic malignant syndrome?
Oft just commenced antipsychotics ATN + renal failure
How do you manage neuroleptic malignant syndrome?
IV fluids to prevent renal failure
Narrow angle glaucoma
How do you withdraw benzodiazepines?
1/8 of daily dose reduction every fortnight
Or switch to equivalent dose diazepam and reduce 2-2.5 mg fortnightly
May take 4 wks to a year to withdraw
Sx of benzo withdrawal
Up to 3 wks after stopping:
Loss of appetite
Enhance GABA by incr duration of Cl channel opening
Only after failure of non pharm methods and refusal of oral meds
With sufficient risk to themselves / others
With sufficient flumazenil on site
2mg IM lorazepam
10mg IM haloperidol