Omeprazole is used to treat certain stomach and esophagus problems (such as acid reflux, ulcers). It works by decreasing the amount of acid your stomach makes. It relieves symptoms such as heartburn, difficulty swallowing, and persistent cough.
Domperidone is an anti-sickness medicine. It helps you to stop feeling or being sick (nausea or vomiting). It can also be used to treat stomach pain if you're having end of life care (palliative care). Domperidone is sometimes used to increase milk supply.
Domperidone+Omeprazole is safe for most of the patients. However, in some patients it may cause common side effects like diarrhea, stomach pain, flatulence, dryness in the mouth, dizziness, headache and other uncommon and rare side effects.