This is specially for BDS students. University exam oriented presentation. If you know this much you can easily score good marks in your 2nd Year

1. PHARMACOLOGY:
ANTIPARKINSONISM
- ARCHI RUNGTA
(BDS)

2. INTRODUCTION
 Parkinsonism is a degenerative disorder
 Extrapyrimadal motor side effect
 Characterized by tremor, anxiety and hypokinesia( reduced movement)
 Secondary symptopms: sialorrhoea(increased salivary flow), gait, mask like face.

3. Mechansim Of Action
Substantia Nigra
Inhibitory Gaba neuron
Release neurotransmitters
Control dopamine secretion
Release dopamine in Nigrostriatal tract Release Ach
Inhibitory dopamine neurons
Cell death
Increase in Ach but fall in dopamine
Triggers abnormal signal
Parkinson

4. CLASSIFICATION
Anti-
Parkinsonism
Drugs
Dopamine
precurson
Peripheral
decarboxylase
inhibitor
Glutamate
anatgonist
COMT-
inhibitor
MAO-B
inhibitor
Dopaminergic
agonist
*Levodopa *Carbidopa *Amantidine *Rasagiline
*Selegiline
*Entacapone
*Talcopone
Drugs Affecting Brain Dopaminergic system
*Bromocriptine
*Ropinirole
*Pramipexole

5. Drugs affecting
Cholinergic system
Anticholinergics Antihistaminics
Biperiden Promethazine

6. LEVODOPA
Only 1-2% of levodopa can cross blood brain barrier
It gets metabolized peripherally and gets converted to dopamine.
And dopamine cannot cross blood brain barrier so levodopa or dopamine
alone cannot be given.
ACTIONS
1. CNS: Marked symptomatic improvement occurs in parkinsonism patients.
Hypokinesia and rigidity are resolved first.
2. CVS: It causes Tachycardia, marked postural Hypotension, Cardiac
Arrhythmias.
3. CTZ: Peripherally formed dopamine gains access to chemo-trigger zone
leads to nausea, vomiting by stimulating D2 receptors.
4. Endocrine: It inhibits prolactin release.
ADVERSE EFFECTS:
1.Nausea and vomiting
2.Postural hypotension
3.Alteration in taste sensation
4.Exacerbation of Angina
5. Cardiac Arrythmias
6.Orofacial Dyskinesia
Fluctuation in motor performances

7. LEVODOPA + CARBIDOPA(100mg/10mg)
As we know Levodopa is not given alone so we need peripheral decarboxylase
inhibitor together with it.
Benefits of this combination:
1. Plasma t1/2 of levodopa is prolonged and dose is reduced to 1/4th.
2. Nausea and vomiting not prominent.
3. Cardiac problems not prominent
4. On-Off effect is minimized
5. On-relief of most of the symptoms
6. Off- loss of beneficial effect of drug
Interaction:
Not given with Phenytoin as Phenytoin decreases the action of Levodopa

8. Dopaminergic Agonists
1. Bromocriptine: Strong D2 agonist and mild D1 agonist
2. Ropinirole: D2 agonist
3. Pramipexole: D3 agonist
Containdications:
1. Recent Myocardial infarction(MI)
2. Angina Pectoris
GLUTAMATE ANTAGONIST(DOPAMINE
FACILITATOR)
NMDA BLOCKER
Synthesis and release of dopamine
They decrease glutamate synthesis, and so decreases excitatory
response.
AMANTIDINE:
Developed as an antiviral drug for ‘Influenza A’
Lower efficacy than Levodopa
Used as a supplement for Levodopa

9. MAO-B Inhibitor
1.They are selective
2. They are Irreversible
3.This inhibitor retards the metabolism of Dopamine
4.Prolongs Levodopa action.
5. Predominantly found in Brain and Platelets
6. “on-off” is minimized.
7. Rasagiline is more potent than selegiline
COMT INHIBITOR
1. Catechol-o-methyl-transferase
2. Selective
3. Reversible
4. COMT plays role in degradation of dopamine and so COMT inhibitors
are used to prevent degradation of dopamine.

10. THANK YOU