.

Parkinsonism caused by any identifiable cause has to be treated. Drug induced parkinsonism responds to withdrawal of the drug but the symptoms may continue for some time.

Drug therapy

Anticholinergic agents

Benxhexol 1-5 mg tid
Orphenadrine 50-100 mg tid

Have useful effect on tremor and rigidity. Do not help hypokynesis. They should be used in early stage of the disease when hypokynesis is not a problem.

Side effects: dryness of mouth, blurring of vision, difficulty in micturation and constipation.

Amantidine 100mg bid or tid

It has mild short lived action on hypokinesis.

Side effects: oedema, confution, seizures.

L-DOPA

The rationale for using L-DOPA is that the enzyme step converting the precursor DOPA to Dopamine is dependant on the concentration of the substrate. Although in parkinsonism the number of dopamine releasing terminals in the striatum is diminished it is possible to overdrive the remaining neurons to produce more dopamine by administering DOPA.
More than 90% of the orally taken L-DOPA is decarboxylated in the gastrointestinal tract to dopamine and only a small amount reaches the brain. If L-DOPA is used alone there is high incidence of side effects such as nausea, vomiting,vasodilatation. This problem is solved by giving a peripherally acting decarboxylase inhibitor. This conmbination therapy pemits use of low dose of L-DOPA.

L-DOPA + Carbidopa
L-DOPA + Benserazide
The combination should be started with low dose and gradually increased. Tremor, Rigidity and hypokynesis are improved.
With the progression of the disease there is loss of capacity to store dopamine. Late deterioration in response to L-DOPA therapy occurs after 3-5 years in 1/3 to 1/2 of patients.
Selegiline and Bromocriptine may be helpful at this stage.

Bromocriptine is preferabley used as a low dose combination with L-DOPA. Especially in young patients who need treatment for many years.

Surgery

Stereotactic thalamotomy is occationaly performed in patients with severe unilateral tremors not responding to drugs.
Implantation of Fetal mid brain or Adrenal cells into the basal ganglion in parkinsonian patients has been tried.

Physiotherapy and Speech therapy is needed to reduce rigidity and to correct posture.

Newer Treatment options for Parkinson's Disease

Dementia - Drug Therapy

Parkinson's Disease - Genetic & Environmental aetiology

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