Patient on treatment on carbidopa + levodopa for 10 yrs now has weaning off effect. What should be added to restore action ?

Ans. is A i.e., Tolcapone Both Entacapone and tolcapone enhance and prolong the therapeutic effect of levodopa-carbidopa in advanced and fluctuating parkinsons disease. They may be used to smoothen off the 'wearing off', increase 'on' time and decrease 'off' time, improve activities of daily living and allow levodopa dose to be reduced. Tolcapone It is a drug used to treat Parkinson's disease (PD). It is a selective, potent and reversible nitrocatechol-type inhibitor of the enzyme catechol-O-methyltransferase (COMT). In comparison with entacapone, another nitrocatechol COMT inhibitor, tolcapone has a longer half life (2.9 hours vs. 0.8 hours) and can better penetrate the blood-brain barrier, acting both in the central nervous system and in the periphery. However, entacapone is less toxic for the liver. Tolcapone improves the bioavailability and reduces the clearance of levodopa and subsequently dopamine from the CNS. Without administration of tolcapone, the beneficial effects of levodopa tend to wear off more quickly, resulting in motor fluctuations.