10 Omeprazole Interactions You Should Know About
Key takeaways:
Omeprazole (Prilosec) is a medication that lowers the amount of acid in your stomach. It’s available over the counter and with a prescription.
Omeprazole can interact with medications that need acid to be absorbed. It can also affect certain medications that are processed through the liver.
In some cases, your healthcare provider may recommend an omeprazole alternative. For example, pantoprazole (Protonix) may be an option with fewer medication interactions.
If you experience heartburn, you may turn to a medication like omeprazole (Prilosec) for relief. Since it’s available over the counter (OTC), it’s a convenient choice to treat your symptoms. But it may not always be the best choice since it can interact with other medications you may take.
Omeprazole is a proton pump inhibitor (PPI). Compared to other PPIs, omeprazole tends to have more medication interactions. That’s because it’s broken down by specific proteins in your liver. And it can block these proteins from breaking down other medications, too. This can worsen side effects and potentially cause more serious problems.
Some omeprazole interactions can be managed. But others should be avoided altogether.
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10 omeprazole interactions to know about
Below we cover several important interactions you should know before starting omeprazole. But this isn’t an exhaustive list. Check with your healthcare provider or pharmacist before combining omeprazole with other medications.
1. Warfarin
Warfarin (Coumadin, Jantoven) is a blood thinner that helps treat and prevent blood clots. Small changes in how much warfarin is in your body can have serious risks. So, people taking it have their blood monitored and dosage adjusted during treatment.
Warfarin is broken down by some of the same proteins as omeprazole. When taken together, omeprazole can cause more warfarin to stick around in your body. Since warfarin prevents your blood from clotting, this can raise your risk of serious bleeding.
Your healthcare provider may suggest a different PPI that’s less likely to interact with warfarin. But if they say omeprazole is OK, they may want to monitor your blood closely. If needed, they may adjust your warfarin dosage. Let them know right away if you notice any new or unusual bruising or bleeding during treatment.
2. Citalopram
Citalopram (Celexa) is a selective serotonin reuptake inhibitor (SSRI) used to treat depression. It’s thought to work by raising serotonin levels in the brain. Like warfarin, it can interact with omeprazole because of how it’s broken down in the liver. This can result in higher citalopram levels in your body.
On its own, citalopram can raise the risk of heart rhythm problems. This risk may go up when it’s combined with medications like omeprazole. And it’s also possible to develop serotonin syndrome — a condition where serotonin levels in your brain get too high. In some cases, serotonin syndrome can be life-threatening.
Because of this interaction, your healthcare provider may lower your citalopram dosage if you’re taking more than 20 mg per day. It’s not known if other PPIs also interfere with citalopram.
3. Digoxin
Digoxin (Lanoxin) is a medication used to treat heart failure and heart rhythm problems. Like warfarin, small changes in digoxin levels in your body can have serious risks. Your blood levels are also routinely monitored while taking it.
Omeprazole can interfere with how much digoxin is absorbed into your bloodstream through your stomach. This can result in higher digoxin levels, and potentially more digoxin side effects.
Even so, it’s not clear how significant these changes are, or if your dosage needs to be changed. Your healthcare provider may monitor your digoxin levels more closely to be sure. They may also suggest a different PPI that’s less likely to interact with digoxin.
4. HIV medications
There are several different medications used to treat HIV. In general, they work by preventing HIV from attacking certain immune cells in your body.
Some HIV medications are known to interact with omeprazole. Examples include rilpivirine (Edurant), atazanavir (Reyataz), nelfinavir (Viracept). This interaction can affect how well they keep your infection under control.
PPIs like omeprazole work by lowering the amount of acid released into your stomach. And rilpivirine, atazanavir, and nelfinavir all need stomach acid to be properly absorbed. Taking them with omeprazole can result in lower medication levels.
It’s important to maintain adequate medication levels in your body to fight HIV. And this helps prevent resistance — when a medication no longer works against HIV. For this reason, you should avoid this combination
Be sure to discuss all medication changes, prescription or OTC, with your healthcare provider. HIV medications often have many interactions.
5. Clopidogrel
Clopidogrel (Plavix) is a blood thinner used for heart attack and stroke prevention. The same protein that omeprazole blocks in the liver is used to activate clopidogrel. When taken together, less clopidogrel gets activated, so it may not work as well. This may raise your risk of heart attack or stroke.
For this reason, it’s recommended to avoid omeprazole if you’re taking clopidogrel. Your healthcare provider can suggest other PPIs that are less likely to cause this interaction.
However, there’s some evidence to suggest that this interaction may not actually lower clopidogrel’s protective effects. If you’re taking these two medications, check with your healthcare provider. They can determine the benefits and risks for your specific situation.
6. St. John’s wort
St. John’s wort is an herbal supplement that some people take for depression. While it’s also available OTC, St. John’s wort has a reputation of interacting with many medications. And omeprazole is no exception.
When taken together, St. John’s wort can cause your liver to break down more omeprazole than usual. This can result in less omeprazole in your body, meaning it may not work as well. So, it’s recommended to avoid this combination.
7. Transplant medications
Transplant medications are vital if you’ve had an organ transplant. Examples include tacrolimus (Prograf) and mycophenolate mofetil (CellCept). However, both of these medications are highly susceptible to interactions with other medications.
Omeprazole can prevent your liver from breaking down tacrolimus. This can potentially lead to more side effects. And some side effects may be serious, like nerve cell damage and heart rhythm problems.
Omeprazole (and other PPIs) can affect mycophenolate mofetil absorption in your stomach. This is thought to be due to lower acid levels. If you absorb less mycophenolate mofetil, you may have a higher risk of transplant rejection.
Like with HIV medications, interactions are common with transplant medications. Your healthcare provider will ensure that your medication regimen is safe and compatible if you’re taking transplant medications.
8. Diazepam
Diazepam (Valium) is a benzodiazepine used to help treat anxiety, seizures, and other health conditions. Like many of the interactions covered above, omeprazole can prevent your liver from breaking down diazepam. This can result in worse diazepam side effects, like drowsiness.
Your healthcare provider may adjust your diazepam dosage if you’re also taking omeprazole. They may also recommend a different PPI that’s less likely to interact.
9. Cilostazol
Cilostazol is a medication used to relieve pain in your legs from walking or exercising. Omeprazole can prevent your liver from breaking it down, resulting in higher cilostazol levels. You may experience more side effects, like headache or diarrhea.
Don’t try to manage this interaction yourself. Your healthcare provider may lower your cilostazol dosage if you’re taking more than 50 mg twice daily. They may also recommend a different PPI.
10. Phenytoin
Phenytoin (Dilantin) is a medication used to treat certain types of seizures. It also has a number of medication interactions, including omeprazole.
When taken together, omeprazole can cause higher phenytoin levels in your body. This can potentially lead to more side effects, such as drowsiness and involuntary eye movements.
Your healthcare provider may monitor your phenytoin levels more closely and adjust your dosage if necessary. They may also suggest a different PPI.
When should I contact my healthcare provider about an omeprazole interaction?
Talk to your healthcare provider before starting omeprazole. This is especially the case if you’re planning on picking up OTC omeprazole from a pharmacy or grocery store. You can also ask your pharmacist about potential medication interactions.
In some cases, your healthcare provider may say it’s OK to combine omeprazole with your medications. They can tell you what to look for if there’s a potential issue with an interaction.
But if you’re ever unsure about an omeprazole interaction or symptoms you’re experiencing, don’t hesitate to ask. And it helps to have your current medication list handy for review.
The bottom line
Omeprazole can interact with clopidogrel, warfarin, and certain HIV medications. Other interacting medications, like citalopram and St. John’s wort, also exist.
In some cases, your healthcare provider may need to adjust the dosage of one or more of your medications. But some combinations should be avoided entirely. Ask your healthcare provider about PPI alternatives that may be safer options with your current regimen.
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References
Aurobindo Pharma Limited. (2022). Digoxin [package insert].
Avet Pharmaceuticals Inc. (2022). Mycophenolate mofetil [package insert].
Bouziana, S. D., et al. (2015). Clinical relevance of clopidogrel-proton pump inhibitors interaction. World Journal of Gastrointestinal Pharmacology and Therapeutics.
Bryant Ranch Prepack. (2022). Cilostazol [package insert].
Bryant Ranch Prepack. (2022). Omeprazole [package insert].
Bryant Ranch Prepack. (2022). Phenytoin sodium [package insert].
Bryant Ranch Prepack. (2022). Tacrolimus [package insert].
Clinical Info. (2021). Guidelines for the use of antiretroviral agents in adults and adolescents living with HIV.
Moradi, O., et al. (2020). Drug-drug interactions among kidney transplant recipients in the outpatient setting. International Journal of Organ Transplantation Medicine.
RemedyRepack, Inc. (2022). Clopidogrel [package insert].
Torrent Pharmaceuticals Limited. (2022). Citalopram hydrobromide [package insert].
Wedemeyer, R. S., et al. (2014). Pharmacokinetic drug interaction profiles of proton pump inhibitors: An update. Drug Safety.
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