PSYCH - PHARMACOLOGY Flashcards
ANTI-PSYCHOTICS
What are the two types of anti-psychotics?
- Typical/1st generation
- Atypical/2nd generation
ANTI-PSYCHOTICS
what is the general mechanism of action for anti-psychotics?
psychosis is thought to be caused be an excess of dopamine
therefore anti-psychotics aim to reduce dopamine by blocking receptors
ANTI-PSYCHOTICS
Give an example of a typical (1st generation) anti-psychotic.
haloperidol,
flupentixol
zuclopenthixol (decanoate = depot)
chlorpromazine
ANTI-PSYCHOTICS
Give examples of atypical (2nd generation) psychotics.
olanzapine,
risperidone (depot),
clozapine,
aripiprazole (depot),
quetiapine
ANTI-PSYCHOTICS
What is the mechanism of action of typical (1st generation) anti-psychotics?
- D2 receptor antagonist
- Reduced release of dopamine from dopaminergic neurones + so reduced electrical activity in dopaminergic pathways
ANTI-PSYCHOTICS
What pathway do typical (1st generation) anti-psychotics work on to have anti-psychotic effect?
Mesolimbic pathway (reduces +ve Sx)
ANTI-PSYCHOTICS
What is the mechanism of action of atypical (2nd generation) anti-psychotics?
- Antagonists at dopamine D2 receptors but more selective in dopamine blockade + so block serotonin 5-HT2a
ANTI-PSYCHOTICS
What is the most crucial adverse effect of clozapine?
- Severe life-threatening agranulocytosis
ANTI-PSYCHOTICS
What are the 5 broad categories of SEs caused by anti-psychotics?
- Extra-pyramidal side effects (EPSEs)
- Hyperprolactinaemia
- Metabolic
- Anticholinergic
- Neurological
ANTI-PSYCHOTICS
What are the extra-pyramidal side effects (EPSEs) of anti-psychotics?
- Acute dystonic reaction
- Parkinsonism
- Akathisia
- Tardive dyskinesia
ANTI-PSYCHOTICS
How does Parkinsonism present?
- Bradykinesia, rigid, resting pill-rolling tremor + postural instability
ANTI-PSYCHOTICS
How does akathisia present?
- Motor restlessness, typically lower legs (can’t sit still)
ANTI-PSYCHOTICS
How does tardive dyskinesia present?
- Purposeless involuntary movements (chewing, lip smacking, blinking, tongue protrusion)
ANTI-PSYCHOTICS
What are the SEs from hyperprolactinaemia?
- Sexual dysfunction (+ anti-adrenergic)
- Osteoporosis risk
- Amenorrhoea
- Galactorrhoea, gynaecomastia + hypogonadism in men
ANTI-PSYCHOTICS
What are the metabolic SEs?
- Weight gain (esp. olanzapine)
- Hyperlipidaemia, risk of stroke + VTE in elderly
- T2DM risk + metabolic syndrome
ANTI-PSYCHOTICS
What are the anticholinergic SEs?
Can’t see, pee, spit, shit –
- Blurred vision
- Urinary retention
- Dry mouth
- Constipation
+ tachycardia
ANTI-PSYCHOTICS
What are the neurological SEs?
- Seizures
- Postural hypotension (anti-adrenergic)
- Sedation
- Headaches
ANTI-PSYCHOTICS
What baseline investigations are done for people starting on anti-psychotics?
- FBC, U+Es, LFTs, lipids, BMI, fasting glucose, prolactin, BP, ECG (QTc prolongation) + smoking status (can reduce effects by enhancing metabolism so issues if suddenly stop)
ANTI-PSYCHOTICS
What regular investigations are done for people on anti-psychotics?
- Lipids + BMI at 3m
- Fasting glucose + prolactin at 6m
- Frequent BP during dose titration
- FBC, U+Es, LFTs, lipids, BMI, fasting glucose, prolactin + CV risk yearly
ANTI-PSYCHOTICS
What specific monitoring is required for clozapine?
- FBC at baseline + weekly for 18w, fortnightly until 1y + monthly after
ANTI-PSYCHOTICS
What happens if a patient does not take their clozapine for 48 hours?
If not taken for 48hr needs retitrating
ANTI-DEPRESSANTS
What monitoring is needed when starting someone on an anti-depressant?
- 2 weekly to ensure dose working + patient stable, may take up to 6w to start working,
- weekly if <30y as increased suicide risk
ANTI-DEPRESSANTS
How should anti-depressants be stopped?
Why?
- Gradual dose reduction over 4w
- Sudden cessation can cause severe withdrawal effects (mostly GI) – pain, diarrhoea, vomiting, restlessness, sweating + mood change
ANTI-DEPRESSANTS
What is the mechanism of action of SSRIs?
Give some examples
- Prevents reuptake + subsequent degradation of serotonin from synaptic cleft by inhibiting its reuptake transporter on the post-synaptic membrane
- Prolonged serotonin in synaptic cleft = prolonged neuronal activity
- Citalopram, sertraline, fluoxetine
ANTI-DEPRESSANTS
What are the side effects of SSRIs?
- GI Sx most common (N+V, hyponatraemia, abdo pain, bowel issues, increased bleed risk)
- Sedation + sexual impotence
- Citalopram + QTc prolongation (dose-dependent)
ANTI-DEPRESSANTS
What are some cautions for SSRIs?
- Suicidal thoughts may increase initially, esp. younger patients
- May precipitate manic phase in bipolar
- 1st trimester risk of CHD, 3rd trimester risk of persistent pulmonary HTN
ANTI-DEPRESSANTS
What are some interactions for SSRIs?
- NSAIDs + aspirin = increased risk of bleeding, co-prescribe PPI
- Can lower seizure threshold
- Do not start until 2w after stopping MAOI + vice-versa as increased risk of serotonin syndrome
ANTI-DEPRESSANTS
What is the mechanism of action of SNRIs?
- Prevents reuptake + subsequent degradation of serotonin AND noradrenaline from synaptic cleft by inhibiting reuptake transporters on post-synaptic membrane
ANTI-DEPRESSANTS
Give some examples of SNRIs?
Venlafaxine, duloxetine
ANTI-DEPRESSANTS
What are some side effects of SNRIs?
- GI (N+V, constipation),
central/peripheral effects (SIADH, rhabdomyolysis)
ANTI-DEPRESSANTS
What is the mechanism of action of monoamine oxidase inhibitors (MAOI)?
- Inhibits monoamine oxidase enzyme which reduces breakdown of adrenaline, noradrenaline + serotonin so increases level
ANTI-DEPRESSANTS
Give some examples of monoamine oxidase inhibitors (MAOI)?
Give some examples.
- Selegiline is selective MAO-B inhibitor which also increases dopamine
- Isocarboxazid, phenelzine
ANTI-DEPRESSANTS
What are some side effects from MAOIs?
- Sexual dysfunction, weight gain + postural hypotension
ANTI-DEPRESSANTS
What are some cautions with MAOIs?
- Increased risk of serotonin syndrome if used with other serotonergic drugs
- Hypertensive crisis with ingestion of foods containing tyramine (aged cheeses, smoked/cured meats, pickled herring, Bovril, Marmite)
ANTI-DEPRESSANTS
What is the mechanism of action of tricyclic antidepressants (TCAs)?
- Prevents reuptake + subsequent degradation of serotonin + noradrenaline from synaptic cleft by inhibiting reuptake transporters on post-synaptic neuronal membrane
ANTI-DEPRESSANTS
Give some examples of tricyclic antidepressants (TCAs)?
Amitriptyline, dosulepin, imipramine
ANTI-DEPRESSANTS
What are the side effects of TCAs?
- Anticholinergic (can’t see, pee, spit, shit)
ANTI-DEPRESSANTS
What cautions are there for TCAs?
- Caution in CVD, avoid following MI
- Cardiotoxic in overdose so caution in suicidal patients (QTc prolongation)
ANTI-DEPRESSANTS
In terms of TCA overdose…
i) mild-moderate Sx?
ii) severe Sx?
i) Dilated pupils, dry mouth, urinary retention, increased tendon reflexes + extensor plantars
ii) Fits, coma, cardiac arrhythmias > arrest
ANTI-DEPRESSANTS
In terms of TCA overdose what are the ECG signs?
Sinus tachy,
wide QRS,
prolonged QT interval
ANTI-DEPRESSANTS
What is the management of a TCA overdose?
Sodium bicarbonate
ANTI-DEPRESSANTS
What is the mechanism of action of mirtazapine?
- Blocks alpha-2 adrenergic receptors > increased release of neurotransmitters
ANTI-DEPRESSANTS
What are some side effects of mirtazapine?
Increased appetite + weight gain + sedation are big ones, also increased triglyceride levels
MOOD STABILISERS
What are some examples of mood stabilisers?
Lithium (first line)
AEDs such as valproate, carbamazepine, lamotrigine
MOOD STABILISERS
What is the mechanism of action of mood stabilisers?
Lithium inhibits cAMP production which inhibits monoamines
MOOD STABILISERS
What is important to note about mood stabilisers?
Narrow therapeutic range 0.4–1.0mmol/L
MOOD STABILISERS
What are the side effects of lithium?
LITHIUM –
- Leukocytosis
- Insipidus (diabetes, nephrogenic)
- Tremors (fine if SE, coarse if toxicity)
- Hydration (easily dehydrates, renally cleared)
- Increased GI motility (N+V, diarrhoea)
- Underactive thyroid
- Mums beware (Ebstein’s anomaly)
Can cause weight gain + derm (acne, psoriasis) long-term too
MOOD STABILISERS
What drugs does lithium interact with?
- NSAIDs, ACEi, ARBs + diuretics may increase lithium levels
- Diuretics = dehydration,
NSAIDs = renal damage
MOOD STABILISERS
What baseline measurements are taken for lithium?
- FBC, U+Es, eGFR, TFTs, BMI + ECG
MOOD STABILISERS
What regular monitoring is done for lithium?
- Weekly serum lithium after initiation + dose changes until stable then every 3m for a year, then every 6m (sample taken 12h after dose)
- 6m = TFTs, U+Es, eGFR
- Annual = BMI
MOOD STABILISERS
What might carbamazepine and lamotrigine interfere with?
- Contraceptive pill
HYPNOTICS
What is the mechanism of action of hypnotics?
- GABA agonists on alpha2-subunit of GABA(A)-BDZ receptor/Cl- channel complex
HYPNOTICS
Give some examples
Zopiclone, zolpidem, BDZs used for hypnotic effect (lorazepam, temazepam)
HYPNOTICS
What are the adverse effects?
Same as BDZs
- Amnesia, ataxia (esp elderly = falls risk), confusion, drowsiness, dizziness next day (hangover effect), tolerance
- Monitor for resp depression (caution in resp disease)
ANTI-PSYCHOTICS
What are the issues for typical anti-psychotics?
Not selective so can bind to other dopaminergic pathways causing generalised dopamine receptor blockade
ANTI-PSYCHOTICS
What pathway do typical anti-psychotics work on to cause side effects?
Nigrostriatal (Parkinsonism),
tuberoinfundibular (prolactin)
ANTI-PSYCHOTICS
What is the benefit of atypical anti-psychotics?
More useful in treating -ve Sx of schizophrenia + less likely to cause EPSEs
ANTI-PSYCHOTICS
What anti-psychotic has a reduced SE profile and why?
Aripiprazole as it is a partial dopamine agonist
ANTI-PSYCHOTICS
What is the most crucial adverse effect of clozapine?
- Severe life-threatening agranulocytosis
ANTI-PSYCHOTICS
What is the most common adverse effect of clozapine?
What other adverse effects may it have?
- Constipation (big issue in elderly)
- Reduced seizure threshold, hypersalivation (Rx hyoscine hydrobromide)