Anti-psychotic drugs Flashcards
what is Schizophrenia charctersied by?
Excessive DA activity
MoA of Anti-Psychotic drugs?
1) Blocks DA receptors (D2>D1) in the brain
2) Blocks 5HT2A receptors
Symptoms of Schizophrenia
1) positive symptoms–> delusion, hallucination, paranoia, agitated behaviour
2) Negative symptoms –> Amotivation, socail withdrawel, anhedonia
3) + cognitive impairments –> Attention and memory
SCZ –> increased level of dopamine in the brain
Changes in the mesolimbic pathways ( ? D2 activity) associated with (?) ve symptoms.
Increases D2 Activity, +ve
Changes in the meso-cortical pathway ( ? D1 activity) associated with ———– and ———— impairment symptoms.
Decreases D1 activity,
Negative and, Cognitive
MoA of 5HT2A receptors in the nigrostriatal pathway?
They control the release of DA
The drug classes of Anti-psychotics + their MoA
1) Typical –> ↓ +ve symptoms (hyperactivity, bizarre ideation, hallucinations, and delusions)
2) Atypical –> ↓ +ve and -ve symptoms.
What mediates the extrapyramidal side effects (EPSs) of the anti-psychotic agents?
Antagonist activity at dopamine receptors in the basal ganglia and other dopamine receptor sites in the CNS
Which autonomic nervous system receptors are antagonized by anti-psychotic agents?
α-adrenoceptors and muscarinic cholinoreceptors
Typical Anti-psychotic drugs
1) Haloperidol,
2) Chlorpromazine
3) Thiothixene
4) Procyclidine
MoA of Haloperidol
Block of D2 receptors > D1 > 5HT2A receptors
Adverse effects of Haloperidol
Extrapyramidal toxicity
Indication of Haloperidol
- Schizophrenia.
- Acute psychotic
illness
MoA of typical Anti-psychotics
- Block brain DA receptors (D2 > D1) in the mesolimbic pathway.
- Block 5-HT2A receptors.
D2> D1> 5HT2A
first line treatment for Schizophrenia?
Typical anti-psychotics (e.g., Haloperidol)
*Atypical anti-psychotic drugs are used if pateint in unresponsive to, or intolerant of, typical anti-psychotic drugs
Indication of Chlorpromazine
- SCZ.
- Bipolar disorder
(manic phase)
AE of Chlorpromazine
Postural Hypotension –> beacuse of α blocaked
*Less sever EPS compared to Haloperidol
Adverse effects of Typical Anti-psychotics
Neurological Effects:
1) Dose-dependent extrapyramidal effects
2) Acute dystonia –> involuntary movements (restlessness, muscle spasms, protruding tongue) –
3)** Parkinson-like syndrome**
4)** tardive dyskinesia**
MoA of Atypical anti-psychotic drugs
Block of 5HT2A > D2 >D1
Atypical Anti-psychotic drugs
1) Clozapine
2) Olanzapine
3) Risperidone
4) Aripiprazole
Indication of Clozapine
SCZ (+ve & -ve symptoms)
MoA of Clozapine
Block of 5-HT2 receptors > D2 > D1.
AE of Clozapine
-
Agranulocytosis; causes severe
neutropenia –> monitor of WBC & absolute neutrophil counts. - Diabetogenic weight gain.
Indication of Olanzapine and Risperidone
- SCZ (+ve & -ve symptoms).
- Schizoaffective.
- Tourette’s Syndrome.
- Toxic psychosis.
AE of Olanzapine
- Diabetogenic.
- weight gain.
AE of Risperidone
Hyperprolactinemia ( ↑prolactin levels in blood)
Indication of Aripiprazole
- Major depression
- Maintenance treatment for biopolar disorder –> in combo with Olanzapine.
Clinical syndrome casued by Atypical anti-psychotic drugs
Malignant hyperthermia
–> Management: Dantrolene, diazepam, and dopamine agonists.
What drug is used to treat Bipolar disorders ?
1) Lithium
2) valporic acid
3) Carbamazepine
Bipolar affective disorder is chracterized by?
Depression and mania
Since Lithium has a slow onset of action, it is normally used in combination of what type of drugs to intitiate the treatment of bipolar disorder ?
1) Anti-psychotics
2) Benozodiazepines –> Carbamazepine or Valproic acid
Drugs used to maintain the tretment of biopolar disroders along with Lithium
Lithium+ Anti-depressant
–> Aripiprazole (Atypical) in combo with Olanzapine (Atypical)
*Aripiprazole –> indicated for major depression and Maintance treatment for BD
AE of Lithium?
Neurologic effects:
1) Ataxia
2) tremor
3) sedation
4) Aphasia
5) Edema
6) others: thyroid enlargment, diapetes insipidus (reversable)
