[PHARMA] ANTIPSYCHOTICS Flashcards
all antipsychotics act on
D2 receptor in mesolimbic system
atypical pyschotics also act on
5HT2 in mesocortical pathway
advantages of typical antipsychotics
cheaper
fast acting IMI & inhalation
long-acting injectable formula for patients struggling to adhere to therapy
central D2 receptors targeted by typical antipsychotics are present in
1-mesolimbic system
2-CTZ
3-Hypothalamus & Pituitary gland
4-Basal ganglia (nigrostriatal area)
blockade of mesolimbic D2 receptor leads to
antipsychotic effect:
-violent patient calms down
-1ry psychosis
-2ry psychosis
blockade of CTZ D2 receptor leads to
antiemetic effect
blockade of basal ganglia D2 receptor leads to
Extrapyramidal side effects (EPS)
blockade of hypothalamus & Pituitary gland D2 receptor leads to
↑prolactin
↑ body weight
gynecomastia ♂
infertility ♂
galactorrhea ♀
amenorrhea ♀
autonomic receptors include
H1
M
α
blockade of H1 receptor leads to
sedation
↑ body weight
blockade of M receptor leads to
atropine-like effects:
dry mouth
confusion
constipation
urine retention
blockade of α receptor leads to
postural hypotension
reflex tachycardia
miscellaneous side effeccts of D2 blockade
cardiotoxic ↑QT
convulsions
corneal-lens deposits
cholestatic jaundice
EPS disorders
akathisia
dystonia
parkinsonism
tardive dyskinesia
neuroleptic malignant syndrome symptoms
muscle rigidity
hyperpyrexia
altered mental status
stupor
unstable BP
myoglobinemia
neuroleptic malignant syndrome occurs due to
rapid excessive central DA blockade in patients sensitive to EPS
management of neuroleptic malignant syndrome
discontinue
muscle relaxants
antiparkinsonian drugs
bromocriptine
akathisia is characterized by
motor restlessness
dystonia is characterized by
muscle spasms
neck torticollis
parkinsonism is characterized by
rigidity
hypokinesia
tremors
parkinsonism is characterized by
rigidity
hypokinesia
tremors
tardive dyskinesia is characterized by
abnormal involuntary movements:
chewing
sucking
fly catching movement of tongue
akathisia occurs due to
blockade of D2 receptors in basal ganglia
dystonia occurs due to
blockade of D2 receptors in basal ganglia
parkinsonism occurs due to
relative increase in cholinergic Ach activity following D2 blockade in basal ganglia
tardive dyskinesia occurs due to
upregulation of DA receptors supersensitivity to DA following chronic blockade of D2 receptors in basal ganglia
akathisia management
propanolol (DOC)
dystonia management
propanolol (DOC)
parkinsonism management
anticholinergics (benztropine)
tardive dyskinesia management
least possible dose
minimal duration
replace w/ atypical antipsychotics or clozapine
antidyskinesia drugs
AVOID ANTICHOLINERGICS
tardive dyskinesia is exacerbated by
anticholinergics
parkinsonism in EPS is relieved by
anticholinergics
low potency typical antipsychotics include
chlorpromazine
thioridazine
high potency typical antipsychotics include
haloperidol
fluphenazine
low potency typical antipsychotics side effect
less central side effects
more autonomic
high potency typical antipsychotics side effect
more central side effects
less autonomic
high potency typical antipsychotics are preferred in
elderly
cardiac patients
atypical antipsychotics advantages
-less central side effects
-less EPS
-less amenorrhea, galactorrhea, -gynecomastia (except w risperidone)
-more efficacy
more selective on mesolimbic system
atypical antipsychotics
improve negative symptoms
atypical antipsychotics
improve positive symptoms
typical antipsychotics
DOC in resistance cases
clozapine
risperidone characteristics
less autonomic
less EPS
less weight gain
↑QT
↑Prolactin
least likely to cause EPS
clozapine
clozapine characteristics
↑autonomic side effects
↑ seizures risk
nocturnal salivation
↑body weight
↑hyperlipidemia (DM risk)
insulin resistance
↑agranulocystosis risk
most likely to ↑ body weight
Olanzapine
olanzapine differs from clozapine in that
it has no risk of agranulocytosis
DOC in psychosis in Parkinson disease
Quetiapine
has extrapyramidal effects & causes akathisia
Aripiprazole
DOC in children
Aripiprazole
DOC in obese & DM patients
Aripiprazole
therapeutic uses of antipsychotics (9)
1-Schizophrenia
2-Mania
3-Bipolar disorder
4-Tranquilizer= Haloperidol
5-Intractable hiccups= Chlorpromazine
6-Antiemetic= Chlorpromazine
7-Autism= Aripiprazole
8-Adjuncts in refractory depression= Quetiapine, Aripiprazole
9-off label hypnotics in insomnia= Quetiapine, Clozapine, Chlorpromazine
monovalent cation
Li+
gold standard in bipolar manic depression
Li+
Li+ uses
mood stabilizers
antimanic
recurrent endogenous depression
refractory unipolar depression
first line TTT for bipolar depression
Li+ or lamotrigine
Li+ onset
5-20 days
Li+ T½
24h
adverse effects of Li+
-CNS= fine tremors, ↓cognition
-GIT= NVD
-Renal= antagonizes ADH->polyuria->thirst
Renal tubular damage
Nephrogenic diabetes insipidus
-Thyroid= benign enlargement with/without hypothyroidism
Li+ toxicity is due to
Narrow TI
Long T½
cumulative
precautions to be taken w/ Li+ therapy
monitor kidney function
monitor thyroid function
monitor serum Li+
adjust dosage in ↓ Li+ excretion
↓Li+ excretion can be due to
Na+ depletion
renal dysfunction
elderly (↓renal function)
Lithium toxicity range
toxic: Li+ >1.5 mEq/l
lethal: Li+ > 2 mEq/l
Lithium toxicity range
toxic: Li+ >1.5 mEq/l
lethal: Li+ > 2 mEq/l
Li+ toxicity manifestations (11)
1-Vomiting
2-Diarrhea
3-Coarse tremors
4-Convulsions
5-Confusion
6-Coma
7-CV collapse
8-arrhythmia
9-ataxia
10-drowsiness
11-slurred speech
Li+ antidote
NONE
Li+ toxicity management
Stop intake
gastric lavage
Activated charcoal in acute ingestion
Diuresis (NEVER thiazide/loop D)
Hemodialysis
hemodialysis is continued for
6-8hr till nontoxic Li+ range
Hemodialysis is most effective in
1-Fluid intake is CI (CHF
Cirrhosis)
2-severe symptoms
3- Li > 3 mEq/l
4-RF
DOC in hepatic impairement
Li+
how does the body deal with Li+
excretes it completely
no metabolism
Li toxicity occurs in Na depletion due to
Li is carried by Na/H exchanger & Na channels
in Na depletion, Li is reabsorbed in place of Na= ↑serum Li= TOXICITY
