Omeprazole and sodium bicarbonate and Phenytoin interaction

Omeprazole and sodium bicarbonate and Phenytoin: both prescribing labels flag this combination with the strongest language, such as a contraindication, a boxed warning, or an instruction to avoid it.

Major

Do not combine without a prescriber's guidance. The label language below is the strongest FDA uses.

What the FDA labels say

From the Phenytoin label · effective 2024-12-24

Major

Calcium carbonate, aluminum hydroxide, magnesium hydroxide Prevention or Management: Phenytoin and antacids should not be taken at the same time of day Antineoplastic agents (usually in combination) Bleomycin, carboplatin, cisplatin, doxorubicin, methotrexate Antiviral agents Fosamprenavir, nelfinavir, ritonavir Antiepileptic drugs Carbamazepine, vigabatrin Other…

Drug interactionsby drug classView label on DailyMed
Moderate

…topiramate Azoles Fluconazole, ketoconazole, itraconazole, miconazole, voriconazole Antineoplastic agents Capecitabine, fluorouracil Antidepressants Fluoxetine, fluvoxamine, sertraline Gastric acid reducing agents H 2 antagonists (cimetidine), omeprazole Sulfonamides Sulfamethizole, sulfaphenazole, sulfadiazine, sulfamethoxazole-trimethoprim Other Acute alcohol intake,…

Drug interactionsby drug classView label on DailyMed

From the Omeprazole and sodium bicarbonate (Konvomep) label · effective 2025-12-16

Moderate

CYP2C19 Substrates (e.g., clopidogrel, citalopram, cilostazol, phenytoin, diazepam) Clopidogrel Clinical Impact: Concomitant use of omeprazole 80 mg results in reduced plasma concentrations of the active metabolite of clopidogrel and a reduction in platelet inhibition [see Clinical Pharmacology ( 12.3 )] .

Drug interactionsnames PhenytoinView label on DailyMed
Moderate

Phenytoin Clinical Impact: Potential for increased exposure of phenytoin.

Drug interactionsnames PhenytoinView label on DailyMed
Moderate

Intervention: Monitor phenytoin serum concentrations.

Drug interactionsnames PhenytoinView label on DailyMed
Moderate

Table 6: Clinically Relevant Interactions Affecting Omeprazole when Co-Administered with Other Drugs CYP2C19 or CYP3A4 Inducers Clinical Impact: Decreased exposure of omeprazole when used concomitantly with strong inducers [see Clinical Pharmacology ( 12.3 )] .

Drug interactionsby drug classView label on DailyMed
Minor

See prescribing information for phenytoin.

Drug interactionsnames PhenytoinView label on DailyMed

Taking more than these two? Interactions stack. Check your whole list at once; it stays in your browser.

Open in the checker

Not medical advice. Interaction Checker quotes FDA label text and NIH fact sheets. Whether an interaction matters for you depends on doses, timing, kidney and liver function, and other conditions. Confirm with a pharmacist or prescriber.