antipsychotics Flashcards
what are typical antipsychotics?
known as ‘first-generation’ antipsychotics, these not only act as antagonists to D2 receptors but also on cholinergic, adrenergic and histaminergic receptors
examples of typical antipsychotics?
Haloperidol, Chlorpromazine and flupentixol.
s/e of typical antipsychotics?
Side effects can therefore be grouped according to receptor blockade:
Dopamine D2 Receptor Blockade
Histamine H1 Receptor Blockade
Alpha-1 Adrenergic Receptor Blockade
Muscarinic Receptor Blockade
what are s/e of Dopamine D2 Receptor Blockade in typical?
Extrapyramidal Symptoms (EPS)
Hyperprolactinemia
what are symptoms of EPS in typical?
what are symptoms of hyperprolactinaemia in typical?
features of H1 receptor blockade in typical?
Sedation: Drowsiness and sleepiness.
features of A1 adrenergic receptor blockade in typical?
Orthostatic Hypotension: A sudden drop in blood pressure upon standing, leading to dizziness or fainting.
features of muscarinic receptor blockade in typical?
Anticholinergic Effects:
Dry mouth.
Constipation.
Blurred vision.
Urinary retention.
what are atypical antipsychotics?
known as ‘second-generation’ antipsychotics, these are D2, D3 and 5-HT2A antagonists, with less overspill into other receptors.
how do atyipcials compare to typical?
as effective and more favourable side effect profile with reduced extrapyramidal effects, but increased metabolic side-effects.
when are atypical antipsychotics used?
1st line for new-onset psychosis
examples of atypical antipsychotics?
risperidone, quetiapine, olanzapine, aripiprazole and clozapine
what are the blockades affected in atypical?
D2 Receptor Blockade:
5-HT2A Receptor Blockade:
Histamine H1 Receptor Blockade:
Alpha-1 Adrenergic Receptor Blockade:
Muscarinic Receptor Blockade:
s/e of D2 blockade in atypical?
s/e of serotonin/5-HT2A blockade in atypical?
Lower Risk of EPS: Atypicals have a reduced risk of causing EPS due to serotonin receptor blockade.
s/e of H1 blockade in atypical?
Sedation: Although less common than with typicals, some atypicals can cause drowsiness.
s/e of A1 adrenergic blockade in atypical?
Orthostatic Hypotension: Some atypicals may cause a drop in blood pressure upon standing.
s/e of muscarinic blockade in atypical?
Anticholinergic Effects:
Generally less pronounced compared to typicals.
Mild dry mouth, constipation, or blurred vision.
what are metabolic effects in atypical?
weight gain
dyslipidaemia + impaired glucose metabolism
elevated prolactin > menstrual irregularities + sexual dysfunction
what other s/e in atypical?
low risk of seizures
QT prolongation
increased VTE and stroke risk in elderly
when should weight be monitored in atypicals?
Weight should be measured at the start of therapy, then weekly for the first 6 weeks, then at 12 weeks, at 1 year, and then yearly.
when should blood glucose be monitored in atypicals?
Fasting blood glucose, HbA1c, and blood lipid concentrations should be measured at baseline, at 12 weeks, at 1 year, and then yearly.
when should prolactin be monitored in atypicals?
Prolactin concentrations should also be measured at baseline.
when should ECG be done in atypicals?
Before initiating antipsychotic drugs, an ECG may be required, particularly if there are cardiovascular risk factors (e.g. high blood pressure), if there is a personal history of cardiovascular disease, or if the patient is being admitted as an inpatient.
when should BP be checked in atypicals?
Blood pressure monitoring before starting therapy, at 12 weeks, at 1 year and then yearly during treatment and dose titration of antipsychotic drugs
what is clozapine?
Clozapine is an atypical antipsychotic that is indicated if there is failure of treatment of 2 other antipsychotic medication, known as treatment-resistant schizophrenia.
what does clozapine treat?
Treats both positive and negative symptoms, slightly more effective than other antipsychotics.
s/e of clozapine?
agranulocytosis, neutropenia, reduced seizure threshold, myocarditis, slurred speech (due to hypersalivation), constipation
what is the most common cause of mortality when related to clozapine use?
constipation
how is clozapine montiored?
weekly FBC for the first 18 weeks of treatment then fortnightly for up to one year, and then monthly.
Blood lipids and weight should be measured at baseline, every 3 months for the first year, and then yearly.
Fasting blood glucose should be tested at baseline, after one months’ treatment, then every 4–6 months.
what is neuroleptic malignant syndrome?
Neuroleptic Malignant Syndrome (NMS) is a rare, but potentially life-threatening, idiosyncratic reaction to antipsychotic medications, particularly those that block dopamine receptors. It typically occurs as a response to the introduction or an increase in the dosage of neuroleptic medications.
features of neuroleptic malignant syndrome?
hyperthermia
fluctuating consciousness
autonomic dysregulation ie fluctuating BP, tachycardia + diaphoresis
rigidity
what ix should be done in neuroleptic malignant syndrome?
how do you manage neuroleptic malignant syndrome?
Discontinuation of Causative Agent
Aggressive cooling measures to address hyperthermia, including cooling blankets and IV fluids to prevent renal failure
benzodiazepines to manage agitation and muscle rigidity
dantrolene - skeletal muscle relaxant
vitals, fluid balance etc
