Clindamycin
"First off if you have difficulty swallowing capsules you will have a hard time with this medicine. I have no problem with normal coated tablets and pills but found it extremely hard to swallow due to it being in a capsule. After 3-4 days of no issues of the 300mg dose for reoccurring strep I had an awful reaction. After I struggled to get it down I quickly (5-10 minutes) started to feel a strong heart burn/acid reflux feeling in my chest. This is common for me so I just took some tums like I normally would and thought I'd be fine. After about 15-20 mins it still wasn't gone and I started to feel extremely nauseous and had to run to the bathroom and proceeded to vomit quite violently. So I stopped taking the medicine."