Why does clindamycin cause heartburn?

Clindamycin can cause heartburn primarily due to its potential to irritate the gastrointestinal tract. As an antibiotic, it disrupts the normal gut flora, which can lead to gastrointestinal side effects, including acid reflux or heartburn. Additionally, clindamycin can relax the lower esophageal sphincter, allowing stomach acid to flow back into the esophagus, further contributing to the sensation of heartburn.