Something to consider if you intend to share your beer with others...quite a few people on various medications can't eat grapefruit. It can make the meds too effective and lead to serious medical problems. I'm one of those people.
I do believe grapefruit negates some antibiotics as well...
OK, figured the pharmacist should weigh in on this.
1) There are no antibiotics that I'm aware of that are affected by grapefruit juice.
2) The compounds that the drug interactions are attributed to are not present in the skin in any great amount. It is mainly in the juice/flesh. For most patients and medications, I'd space the meds and beer apart by 4 hours just to be cautious. In all likelihood, even if it were present in the skins, I doubt there would be enough of the compounds when used in small amounts for flavoring to cause a significant interaction. But we don't know enough to rule it out completely.
3) Grapefruit can make Viagra/Cialis/Levitra more effective. Not pointing the finger at anyone here, but just an FYI. Don't want anyone to have any embarrassing ER visits.
4) Bergamot oil contains the same compounds as those in grapefruit juice that are alleged to cause this interaction. If you have an Earl Grey tea brew, I'd follow the same precautions.
5) Finally, this is just general information and is not intended to be taken as medical advice. If you have any questions specific to the medications that you are taking, consult your doctor or pharmacist.