Soccertese,

I was wondering this as well. According to research, the responsible component of grapefruit is the phytochemical bergamottin. This is perhaps why Ron had such an extra long duration. It boosts the amount of levodopa in our bloodstreams and then it enhances the COMT inhibition leaving more dopamine up there working for us?

Maybe if we are not on entacapone we do not get the extended on time? Just a guess.

Oh, and our genes play a role. I don't know how many have done this but 23 andMe tests for our genetic dispositions with the COMT gene. The Val/Met SNP also informs how well we respond to COMT inhibitors. 23andme will tell you what alleles you have by looking up SNP rs43680 in browse raw data then see abstract for your response to COMT inhibitors at the pubmed link:


The COMT Val158Met polymorphism affects the response to entacapone in Parkinson's disease: a randomized crossover clinical trial.

Laura