I was given antibiotics before my extractions because I had a very bad infection that caused me to be sick for months on end.
After the extractions, they told me no antibiotics were needed, although had heard it was common to get them after oral surgery. My oral surgeon did some major cleaning when I was 'under', and said with having a full mouth extraction done, along with the cleaning she did, there was no need for antibiotics. She said the teeth were causing the infection, and with those gone, the infection would be too.
To date, I have had no problems with not taking meds after surgery. No infection at all.
Talk to your dentist about meds after extraction. Let him/her know your concerns and see what they say. You may not need anything, although I know most people do get prescribed something...it wasn't the case for me.
Good luck to you...
scaredstiff70