Psychopharmacology Flashcards
What are the principles of psychiatric treatment?
Bio Psycho Social model
Combinations more effective
Social interventions important
Name some antipsychotic drugs
First gen (typical) - chlorpromazine, haloperidol, sulpride
Second gen (atypical) - clozapine, lurasidone, olanzapine, risperidole
What are the main effects of antipsychotics?
Sedation, anti-cholinergic, extrapyramidal, hypotensive
What is the MOA of antipsychotics?
Block dopamine receptors - D2 receptors (+ histamine, ACh, 5-HT)
- blockade of mesolimbic + mesocortical pathways gives anti-psychotic effects
- blockade of nigrostriatal gives motor side effects
- Takes a few weeks to become effective
- Control positive symptoms (e.g. delusions, hallucinations), but not the negative symptoms (e.g. social isolation, low mood)
- Atypicals could help with negative symptoms
What are the clinical effects of antipsychotics?
Depression of emotional responses - delusions, thought disorders, perception problems
Sedation - confusion + restlessness
Antiemetic - vomiting
Antihistamine - allergies
Atypical better compliance due to less side effects
What are the clinical indications for use of antipsychotics?
Mainly schizophrenia + acute behavioural disturbances
Can be used as adjuvants in other psychiatric conditions e.g. mania, psychotic depression
What are the pharmacokinetics?
Extensive first pass metabolism
Eliminated by liver metabolism
Given orally or IM injection
What are the adverse effects of antipsychotics?
Mediated by nigrostriatal pathway
- motor symptoms
- acute dystonia, Parkinsonism, akathisia, tardive dyskinesia (after months/years of use)
These effects are less prominent with atypical antipsychotics + do not occur with clozapine
Mediated by tuberoinfundibular system
- prolactin elevation
- galactorrhoea, gynaecomastia, amenorrhoea, impotence
- less common with atypical
Mediated by other receptors
- metabolic side effects
- more common with atypical
- weight gain, dyslipidaemia, T2D, increased risk of seizures
- rarely neuroleptic malignant syndrome which can cause death
(signs: fever, rigidity, hypertension, sweating, urinary incontinence, altered concsiousness)
What are the types of antidepressants?
SSRIS, SNRIs, NASSAs, MAOIs, TCAs
What is the MOA of SSRIs?
Reduce neuronal reuptake of serotonin
- initial increase in serotonin conc, and onset of action delayed for a couple weeks
- increase BDNF + stimulates neurogenesis, moderates limbic system to reduce negative cognitive bias, increases serotinergic transmission
What are the pharmacokinetic properties of SSRIs?
- Well absorbed from gut
- Should be taken in morning to avoid sleep disturbance
- Paroxetine + fluoxetine should not be used in conjunction with TCAs due to toxicity
What are the adverse effects of SSRIs?
Increased anxiousness, emotional numbness, headache, nausea, weight loss/weight gain, vomiting, insomnia
- small increased risk of suicidal thoughts esp. in children
What is the MOA of benzodiazepines?
Type of anxiolytics to treat anxiety
- agonist at GABA-A receptor on separate site from GABA binding site
- increase affinity for GABA - enhance inhibitory effect
Give examples of benzodiazepines.
Lorazepam, diazepam, alprazolam, clonazepam
What are the clinical uses of benzodiazepines?
Anxiolytics, hypnotic, muscle relaxant, anti-convulsant, amnestic
What are the side effects of benzodiazepines?
Headaches, confusion, ataxia, dysarthria, blurred vision
- paradoxical reaction (at risk: children, learning disability, CNS disorder)
- overdose dangerous in comb. with alcohol
What other drugs act on the GABA receptor?
Z-drugs
Barbiturates (amobarbital, phenobarbital)
Flumazenil (antagonist)
Alcohol
What are barbiturates used for?
Rarely used now
- only in severe insomnia, epilepsy, anaesthesia
- highly addictive, dangerous in od
What is flumazenil used for?
Competitive antagonist in benzodiazepine binding site
- can treat overdose
- rapid onset of action but short half-life so needs repeated doses
- no effect on barbiturates as they bind to different site
- should not be used in epilepsy as abrupt withdrawal of benzos can cause seizure
