Anti Psychotic Drug...Report

8/6/2019 Anti Psychotic Drug...Report

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ANTIPSYCHOTIC

DRUGS

REPORTED BY REX MENDOZA


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Psychosis

Losing contact with reality

Characterized by more than onesymptom, but these may include

difficulty in processing information and

coming to a conclusion, delusions ,hallucinations, incoherence, catatonia

and aggressive or violent behavior.


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Modes of Action

All anti-psychotic drugs have inhibitoryeffects on the D2 receptor

Some have actions against the D4receptor

All have other effects - to varyingdegrees

Serotonin blockade (may improvenegative symptoms)

Histamine H1 blockade (drowsiness)

Alpha adrenoceptor blockade (postural

hypotension)


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Clinical Effects

Control the positive features of the disease,but little effect on the negative features(clozapine may be superior in this regard)

The main side-effects are on theextrapyramidal motor system - leading torigidity, tremor, and loss of mobility anddyskinesia

Tardive dyskinesia is a late onset disordercharacterised by repetitive abnormalmovements of face and upper limbs. Thismay be due to proliferation of D2 receptors in

the striatum


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Clinical Effects

Newer atypical anti-psychotic drugs

are less inclined to produce these

effects - possible due to their greateraffinity for the mesolimbic over the

striatal areas of the brain


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Other Effects

some are effective anti-emetics

anti-muscarinic effects lead to dry mouth, blurredvision, difficulty with micturition

Eantagonist effects lead to hypotension antihistamine effects (H1 receptor) lead to

drowsiness

prolactin stimulation may lead to breastdevelopment

agranulocytosis is fairly common with an atypicaldrug - clozapine

Neuroleptic malignant syndrome is a rare butserious effect leading to autonomic instability andhyperthermia


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Classification of anti-

psychotic drugs classical/ typical

chlopromazine (gen)

haloperidol (gen)

fluphenazine (gen)thioridazine (auth)

note: classification isbased on fewer EPS

side-effects,fewer long-term ADRs, efficacy in

treatment-resistantgroups, negative

symptoms

atypical

clozapine (sec100)

risperidone (auth)olanzapine (auth)

quetiapine (auth)


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Phenothiazines

Pharmacologic effects:

(2) autonomic nervous system: block -

adrenergic and M-Cholinergic receptors andresult in hypotension, dry mouth,

constipation and blurred vision.

(3) Endocrine system: increase the release

of prolactin and decrease corticotropin

release and secretion of pituitary growth

hormone.


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Therapeutic uses

(1) treatment of psychotic disorders:schizophrenia, mania, paranoid states,alcoholic hallucinosis.

(2) treatment of nausea and vomitingof certain causes.

(3) anesthesia in hypothermia and

artificial hibernation (used withpethidine and promethazine).


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Adverse Effects

Extrapyramidal motor disturbances: (1)

Parkinson-like symptoms; (2) akathisia;

(3) acute dystonias.

Treatment: anticholinergic


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Adverse Effects

Tardive dyskinesia comprises mainly

involuntary movements of face and

tongue, but also of trunk and limbs,appearing after months or years of

antipsychotic treatment. It may be

associated with proliferation of

dopamine receptors (possiblypresynaptic) in corpus striatum.

Treatment is generally unsuccessful.


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Adverse Effects

Pseudodepression and Schizophrenia-

like syndrome.

Seizures. Cardiac toxicity and endocrine effects.


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Adverse Effects

Other side-effects (dry mouth,constipation, blurred vision,hypotension, etc.) are due to block ofother receptors, particularly adrenoceptors and muscarinic AChreceptors.

Contact dermatitis, blood dyscrasias,obstructive jaundice sometimes occurswith phenothiazines.


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Thioxanthenes

Chlorprothixene: mild antipsychotic

action, and antianxiety and

antidepressant action.


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Butyrophenones

Haloperidol: control psychomotor

excitement.

Adverse effects: severe extrapyramidalsymptoms.


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Others

Clozapine:

(1) be effective in treating some

patients with psychosis unresponsiveto standard neuroleptic drug.

(2) blocks D4 receptor and have lowaffinity for D1 and D2 dopamine

receptors. (3) lacks extrapyramidal side effects.

(4) must monitor the granulocyte

counts weekly.


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Others

Risperidone: be used first episode in

and chronic schizophrenia.

Documents

Anti Psychotic Drug...Report