This presentation mainly focuses upon the use of central anticholinergics in the treatment of parkinson's disease with easy ways to remember!

1. CENTRAL
ANTICHOLINERGICS IN
TREATMENT OF
PARKINSONISM
SRUTHI LAKSHMANAN
RA1841002010134
SRM MEDICAL COLLEGE HOSPITAL AND
RESEARCH CENTRE

2.  Parkinson’s disease is a chronic progressive motor
disorder characterised by tremor, rigidity,
bradykinesia and loss of postural reflexes.

4. DRUGS ACTING ON CHOLINERGIC SYSTEM
 Central Anticholinergics:-
*Trihexyphenidyl (Benzhexol)(most commonly
used)
*Procyclidine
*Biperiden
*Benztropine
 Antihistaminics:-
*Orphenadrine
*Promethazine
*Diphenhydramine

5. MECHANISM OF ACTION
 The central anticholinergics act by reducing the
unbalanced(increased) cholinergic activity in the
striatum of pakinsonian patients.
 They have higher central: peripheral
anticholinergic action ratio than atropine.
 Central H1 antihistaminics also have similar central
anticholinergic property(decreases cholinergic
activity in basal ganglia)

6. THERAPEUTIC USES
These drugs are the treatment of choice (used alone)
in :-
 Drug induced parkinsonism
L-Dopa is not effective in drug induced
parkinsonism because:
*Dopamine receptors are blocked
*There is no deficiency of dopamine
 Idiopathic parkinsonism
 Mild cases (early PD)
 They can be combined with levodopa in an attempt
to lower levodopa dose.

7. THERAPEUTIC USES
These drugs produce 10-25% improvement in
parkinsonian symptoms lasting 4-8 hours after
single dose:-
 Tremor
 Rigidity(muscle stiffness and leg cramps)
 Hypokinesia(little effect)
Sialorrhoea is controlled by their peripheral action.
 Advantages:-
Inexpensive and produce less side effects than L-
Dopa.

8. ADVERSE EFFECTS
 Memory and cognition defects
 Confusional states
 Hallucinations
 Drowsiness
 Blurred vision (dilated pupils)
 Xerostomia (dry mouth)
 Urine retention (dilated bladder)
 Constipation (dry stools)
 Disadvantages:-
They are less effective than L-Dopa.

9. ANTIHISTAMINICS
 Less efficacious than anticholinergics
 Better tolerated by older patients
 Used to potentiate the effects of anticholinergics
 Sedative action helps
 Orphenadrine produces mild euphoriant action

10. SUMMARY
 Only drug of choice in drug induced and idiopathic
parkinsonism
 Act by reducing cholinergic overactivity
 Tremor more benefitted
 Adverse effects
 Antihistaminics- adjuvant to anticholinergics