Using grapefruit juice to affect the CYP3AF enzyme for dutasteride

[Guest]

I was reading about this on alt.baldspot where someone brought it up:

Using grapefruit juice or grapefruit to affect the CYP3AF enzyme. It sounded like a good idea to me, but I'm wondering what people on here think. Doctors always warn us about eating grapefruit or drinking grapefruit juice while on certain medications, because they can increase the concentration of them in our bodies to toxic levels.

Now studies have shown that 2.5 mg of dutasteride reduces far more type I and type II than 0.5 per day.

I'm going to be starting dutas 3x a week soon along with 1.25 mg of finasteride and I thought that if I drink 8 oz of grapefruit juice every day, this may increase the potency of the dutasteride.

And it would be a hell of a lot cheaper than using 2.5 mg of dutas every day.

Any thoughts?

 

[Bryan]

In my opinion, it's somewhat questionable whether the extra dutasteride you get (the effectively greater dose, I mean) is worth the cost of the grapefruit juice. It might be.

Bryan

 

[Guest]

In my opinion, it's somewhat questionable whether the extra dutasteride you get (the effectively greater dose, I mean) is worth the cost of the grapefruit juice. It might be.

Bryan

Hey Bryan,

Well what would you estimate the effect of the grapefruit on the dutas is? Will it quadruple the potency of it like it can for some drugs? I've read that grapefruit can have an effect up to 48 hours before, so it seems that taking a glass of it every other day would have a beneficial affect on retaining more of the dutasteride.

I'm not sure I understand your comment about whether the effectively greater dose is worth the cost. Here's what I think you're saying please correct me if I'm wrong:

Are you saying that it's not worth paying for the grapefruit juice in order to quadruple the concentration of the dutasteride in the blood from 0.5 mg to 2, so to get the extra 1.5 mg per dose of dutasteride? My guess on the increase in potency may be way off, but grapefruit juice has been shown to quadruple the potency of Plandil, a blood pressure medication.

Also, do you happen to know if it's safe to even use the grapefruit juice with finasteride and dutasteride? I remember reading something awhile back about how grapefruit juice should not be combined with finasteride the BPH medication, but I assume that they were referring to a 5 mg dosage. So quadrupling my dosage, if that even happened, would only make mine 5- (1.25 per day*4). I also looked up dutasteride with regard to grapefruit juice and didn't find anything about it, but it is a newer drug.

Thanks

 

[CCS]

grapefruit juice is definitely safe on finasteride.

As for dutasteride, I would NOT want 2mg per day in my blood. I would like to get 4 or maybe even 5 per week for the cost of 2 per week. Please let us know what you find out. I have not yet bothered to buy grapefruit the last few weeks. Forgot to while at the store.

 

[Guest]

grapefruit juice is definitely safe on finasteride.

As for dutasteride, I would NOT want 2mg per day in my blood. I would like to get 4 or maybe even 5 per week for the cost of 2 per week. Please let us know what you find out. I have not yet bothered to buy grapefruit the last few weeks. Forgot to while at the store.

Hey college,

what do you mean by 4 or maybe 5 per week for the cost of 2 per week? 4-5 milligrams for the cost of 2? maybe this could be accomplished by adjusting the amount of grapefruit juice that is drunk.

 

[CCS]

4-5 pill per week for the cost of 2. I'm not really interested in taking a pill every day even if they were free, but anything somewhere close to 3 per week, even 5, is OK with me. I'd just rather use my money on topicals and not worry about systemic effects. The stuff is probably harmless at 1 per day.

How does the grapefruit juice work? Does it over work the liver, or what does it do to that enzyme?

I could just get more juice, but I'd like to know just how much I'm upping my blood concentration.

 

[Guest]

It's thought that flavanoids in the juice affect enzymes in the intestine like CYP3A4. These enzymes are responsible for metabolizing the drugs through the body, but the grapefruit juice flavanoids inhibit it. Consequently, concentrations of the drug in the blood rise.

 

[CCS]

I'm just not that keen on lowing my brain 5ar1 activity that much. Or eliminating all DHT in my prostate. It would be really cool if I could take one pill each week, and have the effect of 4 per week. But I don't want to take 3 per week, and have the effect of 12, or take 1, and get the effect of 1.5 and suffer hair loss. That is why I would like some actual numbers. I just am not optimistic about you finding any since that is grapefruit dose dependent.

I think i will go with a pill every 3rd day and an grapefruit every other day. That should be kind of reasonable.

 

[Mer]

Maybe do a M W F routine and take the Friday dose with the grapefruit since that one will have the longest time before the next dose.

 

[Guest]

good idea mer.

 

[oni]

Why are you taking finasteride with dutasteride? I tried that 2+ years ago (1.25mg finasteride + 0.5mg dutasteride a day). I shed a lot for 4 months on and off it was not fun! :shock:

I got better results from just 0.5mg dutasteride a day and that was 2+ years ago and it's still going strong.

 

[CCS]

the finasteride is a backup incase the dutasteride is fake. we will ditch the finasteride as soon as we know the finasteride is real.

were you taking finasteride with dutasteride 0.5mg/day, or a lower dose? Also, on what part of your head did the shed occure, and how fast did dutasteride regrow it when you got off the finasteride? thanks.

 

[Bryan]

Well what would you estimate the effect of the grapefruit on the dutas is? Will it quadruple the potency of it like it can for some drugs?

I'm sure it hasn't been tested enough with dutasteride to determine exactly how much it increases the effective dose. However, what should be kept in mind here is that dutasteride is already absorbed fairly well, even WITHOUT the grapefruit juice, so I don't see how increasing that percentage a little more is going to make all that much difference. The possibility of quadrupling it seems to be very unlikely.

I've read that grapefruit can have an effect up to 48 hours before, so it seems that taking a glass of it every other day would have a beneficial affect on retaining more of the dutasteride.

Probably. But is it worth the cost of the grapefruit juice itself?

I'm not sure I understand your comment about whether the effectively greater dose is worth the cost. Here's what I think you're saying please correct me if I'm wrong:

Are you saying that it's not worth paying for the grapefruit juice in order to quadruple the concentration of the dutasteride in the blood from 0.5 mg to 2, so to get the extra 1.5 mg per dose of dutasteride? My guess on the increase in potency may be way off, but grapefruit juice has been shown to quadruple the potency of Plandil, a blood pressure medication.

You're right that it increased Plandil that much in that one researcher who first discovered that effect, but even THAT was a bit unusual. Generally, the increase even with Plandil is less than that, according to a Google search I did. Furthermore, only a small percentage of Plandil is normally absorbed anyway, so there was a lot of potential for its absorption to be increased by something like grapefruit juice. I'm sure that the increase in dutasteride is going to be more modest than that, which would bring up the issue again of whether or not it's worth the cost of the juice itself. That would obviously be an even more important consideration if you're using cheaper generic versions of dutasteride.

Also, do you happen to know if it's safe to even use the grapefruit juice with finasteride and dutasteride? I remember reading something awhile back about how grapefruit juice should not be combined with finasteride the BPH medication, but I assume that they were referring to a 5 mg dosage.

The PDR says that the average bioavailability of a 5 mg Proscar tablet was 63% in one study, so what earthly difference could it make if you take it along with grapefruit juice and it increases to somewhere between 63% and 100%? See what I mean? As I've mentioned before, you're talking to someone who wouldn't mind taking as much as 20 mg to 30 mg of finasteride per day in the first place! :wink:

Bryan

 

[CCS]

I doubt the cost of grape fruit juice is an issue for those of us who get our 5 a day and would just substitute it for an orange every other day.


While I agree with the 60% to 100% reasoning in the intestine, I was under the impression from what JayMan said that grapefruit juice somehow turns off or downregulates one of the enzymes in the liver that breaks down Dutasteride. If Dutasteride were metabolized at a slower rate, this could easily double or quadruple the blood concentration, depending on how much the enzyme were suppressed. I would want to know if that would harm the liver, and if a steady state would be reached before dutasteride levels got too high.

I think finasteride is broken down by a different enyzme, at least in the liver.

 

[Bryan]

I doubt the cost of grape fruit juice is an issue for those of us who get our 5 a day and would just substitute it for an orange every other day.

I'm not sure what you mean. Are you saying you're a big grapefruit-juice drinker ANYWAY, whether or not you use finasteride or dutasteride? In that case, yeah, you're saving some money by having that drug-sparing effect.

While I agree with the 60% to 100% reasoning in the intestine, I was under the impression from what JayMan said that grapefruit juice somehow turns off or downregulates one of the enzymes in the liver that breaks down Dutasteride. If Dutasteride were metabolized at a slower rate, this could easily double or quadruple the blood concentration, depending on how much the enzyme were suppressed.

Some substance in grapefruit juice is an inhibitor of the CYP3A4 enzyme, which is a member of a large family of enzymes called Cytochrome P450 which evolved in animals over the eons. They exist in both the intestinal wall (directly affecting things that you eat, right away), and in the liver. Apparently, the intestinal enzyme is considered to have a more important effect than the liver enzyme, at least for certain kinds of drugs. You can find a lot of information on that with a Google search.

I think finasteride is broken down by a different enyzme, at least in the liver.

Both finasteride and dutasteride are degraded by CYP3A4.

Bryan