Adrian C wrote:
Rod wrote:

If you take any of these drugs, you should completely avoid grapefruit
products, tangelos and Seville oranges, unless otherwise directed by
your doctor. Waiting to take these medications — even up to 24 hours —
after you drink grapefruit juice will not prevent an interaction.

Grapefruit also raises post-coffee caffeine levels in the bloodstream,
so is something to be careful (or reckless) with!!

From the site linked above:

"10 subjects with normal blood pressure were given caffeine 3.3 mg/kg
with either water or GJ in a crossover study design. 6 subjects also
participated in receiving multiple GJ doses with caffeine. Twelve-hour
ambulatory blood pressure monitoring was performed on all subjects. The
AUC of caffeine with either of the GJ schedules was not significantly
different from the caffeine AUC when given with water. No significant
differences in systolic or diastolic blood pressure, heart rate or
percentage of time with diastolic blood pressure greater than 90 mm Hg
was observed. The authors concluded that GJ had no effect on caffeine
pharmacokinetics or hemodynamic effects. Caffeine, like theophylline
is mainly metabolized by the CYP 1A2 isoenzymes, while CYP 3A4 may be
responsible for some minor amount of additional metabolism. There was
considerable intersubject variability in this study.39 A previous study
had reported a 28% increase in AUC when caffeine was given with GJ,
though a slightly different methodology was used."

--
Cheers,

John.

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