I have never understood why people taking antibiotics should avoid alcohol although it has widespread popularity.
No medical evidence to show that alcohol impedes antibiotic activity.
Agree with Sqad617, Fluclox is fine. There are a couple of antibiotics which can cause probs when mixed with alcohol, metronidazole (Flagyl) being one of them and cant remember the other off the top of my head but penicillin based ones are fine. If you are female, you should be more worried about them interfering with the effectiveness of the oral contraceptive pill.
It'll make you really tired, most probably bring your guts up and counter act the drug to make it not do its job. So don't drink while taking an antibiotic if you want to get better.
alijangra is quite correct, take care if taking Flagyl (often used for vaginal thrush) Trimethaprin ( bactrin and Septin) and the contraceptive pill being very important as alijangra pointed out.