What is Dexlansoprazole?
Dexlansoprazole, often sold under the brand name Dexilant, is a prescription medication belonging to a class of drugs called proton pump inhibitors (PPIs) [1.5.3]. It works by blocking the final step of acid production in the stomach [1.5.4]. Specifically, it inhibits an enzyme system known as the hydrogen/potassium adenosine triphosphatase (H+/K+ ATPase), or the 'proton pump,' in the stomach's parietal cells [1.5.1]. This action reduces the amount of acid produced, which helps heal acid-related damage to the esophagus, treat heartburn, and manage gastroesophageal reflux disease (GERD) [1.5.5]. A unique feature of dexlansoprazole is its dual delayed-release formulation, which releases the drug at two separate intervals to prolong its acid-suppressing effects [1.5.1].
Why Drug Interactions with Dexlansoprazole Matter
Drug interactions can significantly alter a medication's effectiveness and safety profile. When taken with dexlansoprazole, some drugs can have their absorption reduced, while others can affect how dexlansoprazole is metabolized in the body. Dexlansoprazole primarily lowers stomach acid, which is a crucial factor for the absorption of many other medications [1.5.4]. If a drug requires an acidic environment to be absorbed properly, dexlansoprazole can make it less effective [1.5.4]. Additionally, dexlansoprazole is metabolized by enzymes in the liver, particularly CYP2C19 and CYP3A4 [1.2.1]. Drugs that induce or inhibit these enzymes can decrease or increase the concentration of dexlansoprazole in the blood, respectively, potentially leading to treatment failure or increased side effects [1.2.1].
Major Drug Interactions: What Not to Take with Dexlansoprazole
It is essential to inform your doctor of all medications you are taking, including prescriptions, over-the-counter drugs, and supplements [1.2.2].
Medications Dependent on Gastric pH
Because dexlansoprazole reduces stomach acid, it can interfere with the absorption of drugs that need an acidic environment.
- HIV Protease Inhibitors: Drugs like atazanavir and nelfinavir should not be co-administered with dexlansoprazole, as their absorption is significantly decreased, which may lead to a loss of therapeutic effect and the development of HIV resistance [1.5.4].
- Antifungals: The absorption of certain antifungals, such as ketoconazole and itraconazole, may be reduced [1.2.1, 1.10.4].
- Iron Salts: Dexlansoprazole can reduce the absorption of iron supplements, potentially making them less effective [1.3.1, 1.10.4].
- Other Medications: This interaction also affects ampicillin esters, erlotinib, and mycophenolate mofetil (MMF) [1.2.1, 1.10.4].
High-Dose Methotrexate
A significant interaction exists with methotrexate, a drug used for cancer and autoimmune diseases. Concomitant use of PPIs like dexlansoprazole with high-dose methotrexate may elevate and prolong serum levels of methotrexate and its metabolite, potentially leading to toxicity [1.6.5]. In such cases, a temporary withdrawal of the PPI may be considered [1.6.1].
Warfarin
Taking dexlansoprazole with the blood thinner warfarin may require closer monitoring. While not an absolute contraindication, there is a potential for increased effects of warfarin, and your doctor may need to check your INR levels more frequently [1.2.1].
Diuretics (Water Pills)
Long-term use of dexlansoprazole (typically more than a year), especially when combined with diuretics or digoxin, can increase the risk of developing hypomagnesemia (low magnesium in the blood) [1.4.1, 1.8.1]. Symptoms can include seizures, dizziness, and an irregular heartbeat [1.4.1].
Herbal Supplements and OTC Products to Avoid
Certain non-prescription products can also interact negatively with dexlansoprazole.
- St. John's Wort: This herbal supplement, often used for depression, is an inducer of the CYP3A4 enzyme [1.9.2]. It can speed up the breakdown of dexlansoprazole, making it less effective. Concomitant use should be avoided [1.2.1, 1.9.4].
- Rifampin: Similar to St. John's Wort, rifampin is a strong enzyme inducer and can decrease the effectiveness of dexlansoprazole. It is recommended to avoid using them together [1.2.1].
Food, Drink, and Nutrient Considerations
Unlike some other PPIs, dexlansoprazole can be taken with or without food, which offers flexibility [1.7.1]. There are no specific food or drink interactions reported [1.3.3]. However, long-term use (e.g., longer than three years) may lead to malabsorption of Vitamin B12 due to the reduced stomach acid needed for its absorption [1.8.2, 1.10.3]. Your doctor may monitor your B12 levels [1.10.1].
Comparison Table: Dexlansoprazole vs. Omeprazole
| Feature | Dexlansoprazole (Dexilant) | Omeprazole (Prilosec) |
|---|---|---|
| Mechanism | Proton Pump Inhibitor (PPI) [1.5.3] | Proton Pump Inhibitor (PPI) [1.7.1] |
| Release | Dual Delayed-Release [1.5.1] | Single Delayed-Release [1.7.1] |
| Dosing | Once daily, with or without food [1.7.1] | Once daily, typically 30-60 minutes before a meal [1.7.1] |
| Availability | Prescription only [1.7.2] | Prescription and Over-the-Counter (OTC) [1.7.2] |
| Key Interactions | Methotrexate, certain HIV drugs (atazanavir, nelfinavir), St. John's Wort [1.2.1, 1.6.5, 1.9.4] | Clopidogrel, methotrexate, warfarin [1.2.1] |
Conclusion
To ensure the safe and effective use of dexlansoprazole, maintaining open communication with your healthcare provider is paramount. Always disclose every medication, herbal product, and supplement you are taking. Specific drugs to be particularly cautious of include high-dose methotrexate, certain HIV medications like atazanavir, and the herbal supplement St. John's Wort [1.6.5, 1.2.1]. By being aware of these potential interactions, patients can help minimize risks and achieve the best possible therapeutic outcome. Do not start or stop any medication without first consulting your doctor [1.2.2].
Authoritative Link: For more detailed information, you can review the drug's label on the FDA's website [1.8.2].
