Grapefruit update?

[Buckholt]

A few months ago there were various posts and some suggestion that inhibiting CYP3A4 using Grapefruit juice, could prolong levodopa “on time “. What happened to that idea? Is there any update I might have missed?

[johntPM]

I was one of those posting on grapefruit juice last summer. I am still using it, but in an ad hoc manner. I believe that I'm getting more out of my levodopa (Stalevo in my case). You can see my results by scrolling to the bottom of my homepage.

parkinsonsmeasurement.org/

However, the marginal benefits when grapefruit is taken in addition to Stalevo are not brilliant. Since Stalevo in addition to levodopa already contains two inhibitors (carbidopa and entacapone) there is less to be gained than when used with Sinemet (levodopa and carbidopa). Also, it was hoped that the extra-bioavailability gained from using grapefruit juice would manifest itself in increased half life, rather than increased plasma levels. The graphs tentatively show that the extra area under the curve is split between maximum levels and increased longevity. Just increasing the absorption levels would be of less interest because you can usually get this effect by increasing the levodopa dose; whereas increasing the half-life would give more stable plasma levels, which might lead to a reduction in "off" time and, possibly, reduced levodopa induced dyskinesia.

There was also concern that grapefruit juice would, as a CYP3A4 inhibitor, affect the metabilism of other drugs. Thus leading, in some cases, to overdose and, in others, to underdose. For instance, statins are affected. Every case is different and would need expert analysis.

However, there is the opportunity for those on no other medication than levodopa, to see if grapefruit juice helps them.

[Buckholt in reply to johntPM]

Thanks. I appreciate the detailed response

[Despe in reply to Buckholt]

Here is Wriga's research on GJ:

healthunlocked.com/parkinso...

He has posted more information on GJ. Just search "wriga."

[flyingfoxone in reply to johntPM]

I have tried with my husband and it certainly seems to work for him. I don't give with every dose but just when he seems very off. Maybe two ounces with dose. His total C/L is 1200 per day and he might take the grapefruit juice three times. He does not take any other meds

[johntPM in reply to flyingfoxone]

That's good news. I make your husband's daily dose 0.17 litres. Just to confirm, when you write that "He does not take any other meds", you mean no other meds full-stop, not just C/L?

[flyingfoxone in reply to johntPM]

He only takes Carbidopa/Levadopa. He may have a total of 6 ounces of grapefruit juice a day.

[nychengm in reply to flyingfoxone]

Hi, how are you doing and hoping all is well!

Just wondering if grapefruit juice is working for your husband and using it still to reduce C/L reduction?

In addition, please kindly indicate the quantity and when to take it please!

May I thank you in advance as a carer & my wife (diagnosed with PD 3 yrs. ago) will be grateful as well!

[nychengm]

Hi, how are you doing and hoping all is well!

Just wondering if you've ever tried Grapefruit Juice and if it's working for you and using it still to reduce C/Levodopa reduction?

In addition, please kindly indicate the quantity and when to take it please if you are using GfJ still?

May I thank you in advance as a carer & my wife (diagnosed with PD 3 yrs. ago) will be grateful as well!