Rick,
Your first explanaton as to how this interaction works seems to be the main one. see

It turns out that grapefruit juice can directly or indirectly interact in important ways with a number of medications. This is especially important since grapefruit juice is consumed by approximately one fifth of Americans for breakfast - a time of the day when medications also are commonly taken.

Grapefruit juice blocks special enzymes in the wall of the small intestine that actually destroys many medications and prevents their absorption into the body. Thus, smaller amounts of the drugs get into the body than are ingested. When the action of this enzyme is blocked, more of the drugs get into the body and the blood levels of these medications increase. This can lead to toxic side effects from the medications.

There are over 1 million Americans with PD and if 20% of them take grapefruit juice, it looks fairly safe. The explanation that it blocks the enzyme that breaks down levodopa in the body, before it can get to the brain, explains why i got a boost. As one of your references said, it's effect is like taking a higher dose of Sinemet.
Has anyone else tried it, and got a boost?
Ron

I haven't tried grapefruit juice. Now as much as I dislike the taste of it I will have to try it. I have used orange juice to get my Sinemet working quicker from mouth to brain.

I tried(just this morning) the fresh squeezed ruby red grapefruit by tropicana - did not seem to extend my on time however i did feel a faster onset however i did not take the fava juice - so far fava juice and quercitin are helping me extend that time to 6 hours/pill. (I take usually 2 doses/ day, 1 pill of either 25/100 OR 10/100 generic sinemet) will stay with the grapefruit juice and give it a chance to see. thanks for the thread Ron. my "offs" and "ons" don't really have clear boundaries so its a bit hard to make an immediate assessment

md

Didn't do anything for me - tried 3 mornings.

PD Alchemy is alive and well.

H

I'm thinking grapefruit juice will be useful. My strategy today is to take it 3 hours or so after the sinemet to see if it has a boost effect....seems like it did yesterday. also, will try the bottled white grapefruit juice next!
salut,
md

Ron, I am sure that plays a large part, but look at Cogane...it is plant based.
I think it may have to due with how volatile it is. Seems to inhibit or enhance drug metabolism, but I don't see how they could formulate something for us because think of how many differing interactions they would need to list. Way too much liability involved.

The compound that current researchers name responsible for the "grapefruit effect" is bergamottin, a plant compound that works in a plants defense as in having a bitter taste or toxic leaf. Just look at the root "bergamot"; this is what gives Earl Grey tea its heavenly scent and unusual taste. I am just wondering if a cup of Earl Grey may have a similar effect for some? It seems promising because it comes from the fruit of the plant so that bergamottin goes into the tea. Oh, and one citation it is neuroprotective.


Cell signaling pathways in the mechanisms of neuroprotection afforded by bergamot essential oil

Well, no grapefruit juice, but I will have a cup of Earl Grey in the morning...

I drank about 6 oz of grapefruit juice with meds at 7:00 am yesterday morning.. I had dyskinesia for about 3- 4 hours which is highly unusual for me, but, my on time lasted untill 10 pm.. That is four extra hours of on time

So I decided to try it again today, only this time I drank the juice 30 minutes before meds

I will report back later...........

Hi Steven,
Thank goodness someone has duplicated my experience. Do I understand right that you had one dose at 7.00am which gave you an on until 10.00pm.? Assuming you switched on at 8.00am, that would mean 14 hours on time from one dose!! You had no other doses during the day?
What size dose of levodopa did you take, and did you take any other drugs in your 7.00am dose?
I am not surprised you got dyskinesia, the grape juice acts as if you had taken a larger dose than you actually did.
Thanks for your input
Ron

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