I ve been prescribed Amoxicillin by a dentist, 4 pills 1 hour before each of 5 upcoming visits, I thought as a pain preventative. But I read that it s an anti-bacterial, and probably meant to clean my mouth since it s been a while since I ve visited my dentist (having been preoccupied with lung cancer care (Opdivo, which has eliminated the lung nodules). Still, I now wonder if mouth bacteria might cause pain during dental extraction, bridge building, and cavity repair. I ask because a friend in San Diego is also having dental work and describes it as the most painful dentistry ever. Should I advise him or not, to get his dentist s opinion regarding Amoxicillin (for his pain), or forget about it?