The Role of COMT inhibitors as

Anti-Parkinsonisms

الله بسمالرحيم الرحمن

By\Hasnaa Ahmed Salama

Alexandria Faculty of Medicine

Points to discuss :1) Function of COMT enzyme.2) How COMT inhibitors work.3) Preparations : Entacapone ,Tolcapone , Stalevo.4) Adverse effects.

COMT Substrates L-Dopa + Catecholamines

COMT 3-OMD

SAM SAH

COMT inhibitors

xDopamine

DDCDDCI x

Mechanism ??

Then,how they work?!

1. L-dopa degradation.

2. L-dopa in the blood.

3.+DDCI L-dopa in the blood.

Note Always taken with L-dopa, as they have no effect alone.

Preparations….Entacapone

TolcaponeStalevo

Entacapone ( Comtan®)200 mg 8/day

L-dopa Carbidopa(DDCI)

a great Reduction in the manifestations of

parkinsonian syndrome.

Contraindications :1) Hypersensitivity.

2) Isocarboxazid (MAOI) Possible hypertensive.

3) sympathomimetics their effect & toxicity.

Tolcapone ( Tasmar®) 100&200 mg

3/day

Structurally and pharmacologically related to Entacapone but…. It causes

Liver toxicity

Monitor liver functions

Stalevo(LCE)

1-Diarrhea. 2- Vivid dreams and visual hallucinations. 3- Drowsiness. 4- Urine discoloration (orange). 5- Dyskinesias. 6- nausea and vomiting. 7-Tolcapone liver toxicity.