What are Prilosec (omeprazole) side effects?

Potential side effects of Prilosec include: 

• Gas
• Constipation
• Nausea
• Vomiting
• Diarrhea
• Headache

Talk to your doctor if these Prilosec side effects are severe or do not go away. 

More serious side effects of Prilosec that require immediate medical attention can include: 

• Rash, hives, itching, swelling of the face, hands, feet, difficulty breathing or swallowing (allergic reaction)
• Dizziness, lightheadedness
• Blood in urine and change in urine output (kidney problems)
• Fast, irregular, or pounding heartbeat, muscle spasms (low magnesium)
• Excessive tiredness or weakness
• Severe diarrhea, stomach pain, loss of appetite

The above list may not include all the potential side effects of Prilosec. Speak to your doctor if you have severe side effects or if your side effects do not improve over time. You can also report unusual Prilosec side effects to the Food and Drug Administration at 1-800-FDA-1088.

Prilosec Overdose: In case of a known or suspected overdose, call your doctor or pharmacist immediately or call the poison control helpline at 1-800-222-1222. If a person has collapsed, had a seizure, has trouble breathing, or cannot be awakened, call 911 immediately.