Grapefruit and ed meds

I have seen warnings not to eat grapefruit and then take ed meds. How long would you have to wait to make sure it's ok between grapefruit intake and taking ed meds?

Grapefruit juice inhibits the enzyme that metabolizes a lot of drugs. It's effect lasts 72 hours. If you take your ED meds with grapefruit juice it will last longer in your body and its effect may be enhanced, as well as any side effects like low blood pressure.

It depends on the ED med. Viagra is pretty much gone after a few hours; Cialis is still effective for 36 hours.

What do you find confusing? With grapefruit juice, they do stay in the body longer, are effective longer, and the side effects last longer too.

Allen explained the issue properly. But you can think about it in a slightly different way as well:

As an example, Pharma has decided that 5 mg of their drug is the appropriate dose for a certain group of patients. Their pharmacological data are based on that amount. But eating the grapefruit makes the 5 mg act more like you ingested 7.5 mg of the drug because the drug will stay longer in your system. Since Pharma's data (submitted to the FDA for approval etc) are based on 5 mg, taking this amount with the grapefruit would invalidate their data and possibly be dangerous. That's why there is a warning.
Or stated yet another way, whereas 5 mg of the drug might be safe for the patient, with the effect of the grapefruit added, this amount might not be.

Post Edited (Sr Sailor) : 2/22/2017 3:57:49 PM (GMT-7)

Don't ever drink grapefruit juice if you are depending on ED-meds. You never know when there is an opportunity for sex and it would be terrible to miss it.

I can't speak specifically as to the effects of grapefruit juice on ED-meds, but I know for a fact that grapefruit juice INVALIDATES, ie, renders INEFFECTIVE, some of my Lupus meds. Consequently I have not had grapefruit for over a decade.

I would speak to my Dr and/or my pharmacist rather than relying on the internet (including well-meaning people here) before assuming medications are made more or less effective by grapefruit juice!!!

Pharmacist Daughter says stay away from grapefruit / juice if you take any kind of meds including ED. Logically you would think it would prevent the meds from working but it's actually the opposite, at least for the ED meds.

The meds are broken down by an enzyme in your gut and grapefruit juice inhibits the breakdown so you can potentially get to high of a level of meds in your bloodstream. The impact grapefruit has varies person to person and even day to day in the same person based on how much you ingest and the amount of enzyme you start out with.

The variability is what causes the problem. If you intend to take 5mg Cialis daily and you take it with grapefruit your level will be higher than the intended dose. How much higher who knows? Will it cause a problem who knows? Just easier to stay away from grapefruit/juice if you take any kind of meds or know for certain the meds you take are not impacted by grapefruit.