A patient presented with symptoms of drug-induced Parkinsonism including tremors, bradykinesia, and loss of balance after taking the antipsychotic drug haloperidol for 6 months. Diagnostic tests including a DAT scan confirmed dopamine receptor degeneration due to long-term haloperidol use. The patient was diagnosed with drug-induced Parkinsonism and treated by withdrawing haloperidol, starting domperidone for symptoms, and using clozapine. Clozapine has multiple mechanisms of action including antagonism of serotonin and dopamine receptors that differentiate it from typical antipsychotics.

1. DRUG INDUCE PARKINSONISM
Symptoms:
Tremorsat rest
Brady Kinysia
Loss of Balance
Monotonus
Diagnostic test:
DAT Scan
PET Scan
CT scan
DAT Test:
Ioflupane is the International Nonproprietary Name of a phenyltropane compound
which is a neuro-imagingradiopharmaceutical drug, used by nuclear
medicine physicians for the diagnosis of Parkinson's disease and the differential
diagnosis of Parkinson's disease over other disorders presenting similar symptoms. It is
injected into a patient and viewed with agamma camera in order to
acquire SPECT images of the brain with particular respect to the striatum, a subcortical
region of the basal ganglia.
Medical History:
Use of Haloperidol 100mg from 6 months = 1+1( anti psychotic drug)
Mechanism Of action of Haloperidol :
Diagnosis:
Dopamine level is not effected but dopamine Receptor temporarily degenerated due to
continuous use of Haloperidol from 6 month and confirmed by DAT Scan.

2. Managementand treatment:
 Haloperidol Drug withdraw
 Domperdione for symptomatic treatment 1 + 1
 Use of Clozapine
MOA of Clozapine:-
Clozapine has multiple clinical advantages that differentiate it from typical
neuroleptics but that it may share with other novel antipsychotic drugs such as
risperidone and olanzapine. There may be more than one pharmacologic feature
that contributes to its advantages in improving psychopathology, cognition, affect,
tardive dyskinesia, etc. Clozapine has < 10 nM affinity for the serotonin (5-HT)2A,
5-HT2C, 5-HT6, 5-HT7, D4, m1, and alpha 1-adrenergic receptor but weak
affinity for the D2 receptor. Current evidence suggests the 5-HT2A and D4
receptor antagonist properties of clozapine, together with its weak D2 blocking
properties, contribute the most to its advantages and should be sought in drug
development programs. However, the other effects of clozapine may also be
contributory. Clozapine is effective in a variety of conditions and at a range of
plasma levels. The effects that are important in various indications may differ.