Psychopharmacology Flashcards
Antipsychotics/Neuroleptics general mechanism
Dopamine receptor antagonists - produces antipsychotic effect (especially D2 receptors)
Many of these drugs are multipotent antagonists and also block 5-HT, cholinergic, H and alpha recptors
Examples of extra-pyramidal side effects
Acute Parkinsonism
Akathisia (feeling of needing to move constantly)
Acute dystonic reaction (follows sudden dopamine reduction)
Tardive dyskinesia
Major adverse effects of neuroleptics
Extrapyramidal effects
Sedation
Disturbances in thermoregulation
Cardiovascular e.g. prolonged QT interval
ANS effect (anticholinergic effects)
Metabolic and endocrine (e.g. weight gain, impaired glucose and lipid metabolism)
Drugs which may induce depression
B-blockers Calcium channel blockers Benzodiazepines Methlydopa, levodopa Corticosteroids Anabolic steroids
SSRI mechanism of action
Selective, potent inhibition of serotonin reuptake via inhibition of the serotonin transporter
Monoamine hypothesis of depression
Depression occurs due to a relative deficiency of monoamines signalling in the brain
SSRI examples
Fluoxetine
Citalopram
Serotonin syndrome mechanism
Massive amount of serotonin at synapse, so serotonin non-specifically binds to other receptors at synapse
Caused by certain drugs e.g. cocaine, LSD, SSRIs (NB when used in combination with inhibitors)
Signs/symptoms of serotonin syndrome
Mydriasis (pupil dilatation)
Diaphoresis (sweating)
Agitation/excitement
Tachycardia
Autonomic instability - often hypertensive
Tremor, hyperreflexia and clonus (esp in lower extremities)
TCA mechanism of action
Amitriptyline - balanced norepinephrine/serotonin reuptake inhibitor
Imipramine - preferentially inhibits the reuptake of serotonin (by at least 10 fold over norepinephrine)
TCA side effects
Drowsiness Hypotension Weight gain Dizziness Blurred vision
TCA overdose
Coma
Seizure
Arrhythmias
Cardiac arrest
Anxiety treatment logic
Anxiety is opposite end of spectrum to depression –> treat by stimulating release of inhibitory neurotransmitters (GABA)
Benzodiazepines mechanism
Binds to allosteric (non-active) site on GABA receptors and increases frequency of GABA receptor opening per second –> more time for chloride to enter neuron –> hyperpolarisation
[endogenous GABA still required for this effect]
Barbiturates mechanism
Keep GABA channel open longer –> more time for chloride to enter neuron
[endogenous GABA still required for this effect]
