Both rabeprazole and omeprazole belong to the same class of medicines called proton pump inhibitors (PPIs), which reduce stomach acid. The main difference is that rabeprazole typically begins working faster and is processed more consistently by the body than omeprazole. While they can often be substituted for one another because they serve the same purpose, they are not identical. The equivalent dose may vary depending on your specific health needs. Please consult your doctor or pharmacist before making any switch to ensure it is safe and appropriate for your treatment plan.