Antipsychotics Flashcards
Mention role of dopamine receptors in schizophrenia & effect if drugs
Positive symptoms result from inc dopamine activity on D2 receptor in mesolimbic pathway
Negative symptoms result from dec dopamine activity on D2 receptor in PFC or mesocortical pathway
All antipsychotics block D2 receptor
Atypical antipsychotics only block 5-HT2A, thus inc dopamine in PFC
Mention advantages of typical antipsychotics
Cheaper
Fast actibg IM (Haloperidol) & inhalation of agitation
Long acting injectiable “depot” formulations for patients who can’t adhere to treatment
Mention uses of typical antipsychotics
I. Antipsychotic
1. Violent patient
2. 1ry psychosis: dec hallucinations & delusions in few weeks
Schizophrenia, mania in bipolar depression, psychotic depression
3. 2ry psychosis: brain tumour, cocaine, dementia
II. Antiemetic
Enumerate side effects of antipsychotics D2-action
- Extrapyramidal side effects
- Inc prolactin: gynecomastia, galactorrhea, amenorrhea, infertility
- Inc body weight
Enumerate effects of antipychotic autonomic blockade
H1: sedation, inc body weight
M: atropine side effects
A: postural hypotension
Mention miscellaneous side effects of antipsychotics
Cardiotoxic (inc QT)
Convulsions
Corneal lens deposits
Cholestatic jaundice
Enumerate extrapyramidal side effects of antipsychotics with mechanism
Akathisia, dystonia, both due to D2 blockade in basal ganglia
parkinsoism, due to D2 blockade in basal ganglia+ relative inc in cholinergic activity
Tardive dyskinesia: supersensitivity of DA receptors following choric blockade
Neuroleptic malignant syndrome due to excessive rapid blockade of DA receptors in patients sensitive to extrapyr effects of neuroleptics (idiosyncrasy)
Describe managment of extrapyramidal side effects of antipsychotics
- Propronolo for akathesia
- Anticholinergics: benzotropine may be given routinely with antipsychotics as prophylaxis against extrapyramidal side effects but may exacerbate tardive dyskinesia
Describe symptoms & management of neuroleptic malignant syndrome
Muscle rigidity, hyperpyrexia, stupor, altered mental status, myoglobinemia, unstable BP
Managed by dicontinuation of antipsychotic, muscle relaxant (dantrolene, diazepam), antiparkisonian durgs, DA agonist bromocriptine.
Compare high & lowotency typical antipsychotics
Low: chlorpromazine & thioridazine, less autonomic side effects, more autonomic & miscellaneous side effects
High: haloperidol, fluphenazine, more central side effects, lessautonomic & miscellaneous thus preferred in elderly/cardiac patients
Enumerate advantages of atypical antipsychotics
- Less central side effects: less extrapyramidal s.e. & less prolactin induced side effects (ex respieridone)
- More efficacy as they improve negative symptoms also.
…….is effective & reserved for resistant cases
Justify.
Clozapine
Due to inc risk of agranulocytosis & seizures, inc autonomic side effects & inc body weight & insulib resistance (INC DM), but has least central side effects
Disadvantages of resperidone
Inc prolactin & QT interval
The antipsychotic causing most inc body wight is….., while…..is of choice in Parkison disease with psychosis, it is also used as……
Olanzapine
Quetiapine
Off-label hypnotic
Mention advantages & disadvatages of aripiprazole
More extrapyramidal side effects esp akathesia
Favourable on cognitive function (preferred in children)
Lesser effect on body weight & lipids (preferred in obese & DM pateints)
As regards antipsychotics, ….is used as tranquilizer, while……is used in severe emesis & intractable hiccups, …….are used in autism, ……are used in refractory depression, while…..are off-label hypnotics.
Haloperidol
Chlorpromazine
Resperidone & aripiprazole
Aripiprazole & quetiapine
Quetiapine, clozapine & chlorpromazine
Enumerate uses of lithium carbonate
Mood stabilizer, anti-manic, recurrent endogenous depression, adjunct to antidepressants in refractory unipolar depression.
First line treatment for bipolar depression is…….
Lithium or lamotrigine
Mention adverse effect of Li
CNS, fine hand tremors and dec cognition
GIT upset
Renal: antagonizes ADH (polyuria and thirst) nephrogenic diabetes insipidus, renal tubular damage.
Thyroid benign enlargement with or without hypothyroidism
Toxic drug: narrow TI (Th 0.6-1.2 and TOX at more tgan 1.5 mEg/l), long t1/2, cumulative.
Mention precautions of Li administration
- Coarse tremors and inc GIT symptoms are early warning signs of toxicity
- Monitor kidney and thyroid function
- Monitor Li serim level
- Adjust dose in reduced Li excretiom as in Na depletion by diuretics, renal dysfunction, old age (dec renal function)
Manifestations of Li toxicity
Vomiting, diarrhea, coarse tremors (early signs)
Ataxia, drowsiness, slurred speech, arrhythmia, CV collapse
Confusion, convulsions, coma
Describe managemney of Li toxicity
Stop Li, gastric lavage and A.charcoal if acute intake
Inc fluid intake (maintain electrolytes)
Diuresis, osmotic or forced (never thiazide or loop)
Dialysis: hemo- or peritoneal (hemo- more effective esp if severe toxicity or if fluid intake CI) repeated every 6-8 hrs
