Domar-O Injection is administered for treatment of gastroenteritis, peptic ulcer disease, GERD, and Zollinger-Ellison syndrome. It comprises ondansetron and ranitidine as active compounds that are selective serotonin 5-HT3 receptor antagonists. This injection also shows affinity for parietal cells of stomach where it works by blocking to H+/K+ ATPase pump and inhibits excessive gastric acid production. Domar-O Injection gets metabolized in liver by CYP3A4, CYP1A2, CYP2D6, & FMO3. It is known to provide relief from heartburn, duodenal ulcers, erosive esophagitis, and bleeding of upper GI tract. It can be administered via intravenous & intramuscular routes.