Hi, I understand your concern. Levaquin is an antibiotic (levofloxacin) used to treat infection of prostate (prostatitis). Usually, its use is associated with constipation sometimes following previous diarrhea of first day use. It s very important to take plenty of fluids. Can take metamucil along with probiotics, psyllium supplement and senna supplement to help ease a bowel movement. If still no improvement, contact your physician immediately to rule out other possible causes to your severe constipation. Wish fast recovery.