Psych drugs Flashcards
Name some tricyclics
imipramine, dosulepin, amitriptyline, lofepramine
when to use tricyclics
Mainly chronic pain and sometimes depression
tricyclic mech of action
Block the reuptake of monoamines (mainly noradrenaline and 5-HT) into presynaptic terminals
when not to use tricyclics
In manic phase of bipolar
When to use SSRIs
Depression
Name some SSRIs
fluoxetine, citalopram/escitaloprim, sertraline
SSRI mech of action
- Selectively inhibit reuptake of serotonin (5-HT) from the synaptic cleft
- Escitalopram probably best all round SSRI
- Dose dependent QT prolongation
- Sertraline is well established, has a good cardiac safety profile and allows easy dose titration
- Mirtazapine promotes sleep and appetite/weight gain, less likely to cause nausea or sexual side effects
- Fluoxetine has the longest half-life so least discontinuation syndrome, only SSRI licensed for under 18s
SNRIs name
venlafaxine, duloxetine
Contraindications to SSRIs
Not in Manic phase
Give PPI if pt on NSAID
Mirtazapine if on warafarin
No if they are on triptans
No in preg
When to use SNRIs
- Major depression
- Generalised anxiety disorder, social anxiety disorder, panic disorder
- Duloxetine is also good for neuropathic pain and urge incontinence
SSRI and SNRI side effects
- GI - nausea, vomiting, dyspepsia
- CNS - dizziness, agitation, insomnia, headache
- Spinal - sexual dysfunction
- Misc. - dry mouth, bleeding disorders, weight loss, hyponatraemia in elderly
- Can cause transient increase in self-harm/suicidal ideation, especially in < 25 years
- Also cause discontinuation effects: mood change, dizziness, nausea, diarrhoea, headache
SNRIs mech of action
- Block the reuptake of monoamines (noradrenaline and 5-HT) into presynaptic terminals - block SERT and NET
- May be slightly more effective than SSRIs but associated with a higher rate of adverse effects
- Venlafaxine - SSRI at low doses, at higher doses starts targeting noradrenaline receptors
Contras to SNRIs
in uncontrolled hypertension
Name some atypical antidepressants
Mirtapine, trazodone, bupropion
Mirtapine mech and side effects
- Mixed receptor effects - blocks ⍺2, 5-HT2 and 5-HT3
- Side effects - weight gain (increases appetite) and sedation
- Less of the other side effects than SSRIs or venlafaxine
- Can be used synergistically with SSRIs and blocks serotenergic side effects
Name some 1st Gen dopamine antagonist (typical antipsychotics)
haloperidol, prochloperazine, fluphenazine, chlorpromazine, trifluperazine
1st gen Dopamine antagonists mech of action (typical antipsychotics)
- Non-selectively block D2 and other receptors
- Reduce positive symptoms
When to use first gen dopamine antagonists (typical antipsychotics)
Haloperidol is commonly used for delirium or psychosis
Others for schizo and bipolar
1st gen Dopamine antagonists side effects (typical antipsychotics)
Worsen negative symps, extra-pyramydal side effects (parkinsonism, dyskinesia), Neuroleptic malig syndrome, hyperprolactinaemia, restless legs
2nd gen dopamine antagonists (atypical antipsychotics) names
olanzapine, rispiridone, quetiapine, aripiprazole, clozapine, amisulpride, lurasidone
Atypical (2nd gen) antipsychotics mech of action
- Work on D2 and 5HT-3 (serotonin) to reduce side effect profile
- Also work on H1, alpha and cholinergic
- Reduce positive symptoms with no worsening of negative symptoms
- Less likely to cause extra-pyramidal side effects
- Clozapine is better for treatment non-responders
Contras to clozapine
- Strict monitoring protocol for clozapine due to side effects
- ECG and FBC before starting
- FBC every week for 18 weeks then every 2 weeks thereafter
- Patient must notify if started or stopping smoking
- Weight calculated on each visit to ensure dose remains in therapeutic range
Atypical (2nd gen) antipsychotics side effects
- Risperidone is most likely to cause EPSE and increased PRL side effects (e.g. galactorrhoea)
- Olanzapine - metabolic syndrome
- Quetiapine - sedation and weight gain
- Clozapine - agranulocytosis, neutropenia, seizures, metabolic syndrome, weight gain and sedation
Name some benzos
Midazolam, clonezepam
when to use benzos
Short-term (2-4 weeks) management of anxiety
benzos mech of action
- Positive allosteric modulators of GABAa receptors in the CNS
- The GABA-A receptor is an inhibitory ionotropic receptor
- Benzodiazapines will increase the Cl- entering the neurons, resulting in membrane hyperpolarisation producing an inhibitory postsynaptic potential → reduced neuronal firing
Contras to benzos
- Avoid prolonged use - develop tolerance, are addictive
- Avoid in pregnancy
- Risk of foetal malformation, ‘floppy baby syndrome’, also lethargy with breastfeeding
- Increase falls risk, can worsen delirium also
Benzo side effects
Rapid action, well tolerated, efficacious but can be problems (particularly if used over 2 weeks):
- Sedation and psychomotor impairment
- Discontinuation/withdrawal problems
- Dependency and abuse - hence only used for short term
- Alcohol interaction
- Can worsen co-morbid depression
When to use lithium
Management of bipolar affective disorder:
- Acute treatment of symptoms - to reduce mood in episodes of mania and raise mood in episodes of depression
- Long term treatment - to stabilise mood and prevent recurrence of both mania and depression
contras to lithium
- If possible avoid in pregnancy (particularly 1st trimester) and breast feeding
- Associated with Ebstein’s anomaly of the heart
- Medication-free pregnancy is suggested for women with less severe illness and good supports
- Full or partial prophylaxis with a mood stabiliser is recommended for women at higher risk of relapse
- Drug interactions predisposing to toxicity include medications such as NSAIDs, furosemide, thiazide diuretics, ACE inhibitors and some antidepressants
lithium side effects
- Dry mouth/strange taste
- Polydipsia and polyuria
- Tremor
- Fine tremor seen at therapeutic dose - coarse tremor indicates toxicity
- Hypothyroidism
- Long term reduced renal function
- Nephrogenic diabetes insipidus
- Weight gain
- Toxic effects:
- Vomiting
- Diarrhoea
- Ataxia/coarse tremor
- Drowsiness/altered conscious level
- Convulsions
- Coma
Side effects of sodium val
teratogenicity (neural tube defects)
