Brief Answer:
yes it is, but not in case of boils..

Detailed Answer:
Hello xxxxxxx, Welcome to HCM,
I've gone through your query and understand your concern,

In general, you should note that boil or furuncle are infections mainly caused by aerobic bacteria for which Penicillin group of antibiotics are the first choice (as your doctor has rightly prescribed Clavum or Co-Amoxyclav in this case)..

While, Metronidazole is a potent antibiotic & antiprotozoal drug which is primarily effective against anerobic bacterial infection.. So my thought is, there must be another source of infection for which your doctor has now prescribed the Metrogyl..the bifilac is given to combat against any gastric upset due to antibiotics..

You can safely take them though, don't worry ..drink plenty of water during the antibiotic course to remain well hydrated and complete the full course of antibiotics without any miss..

Seems like your in good hands only, don't worry..

Wish you good health and quick recovery

Take Care
Kind Regards

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