Can you take omeprazole and levothyroxine together?

In this article:

• Can you take levothyroxine and omeprazole together?
• Taking levothyroxine and omeprazole together
• How far apart should levothyroxine and omeprazole be taken?
• Omeprazole and levothyroxine comparison

In this article

• Can you take levothyroxine and omeprazole together?
• Taking levothyroxine and omeprazole together
• How far apart should levothyroxine and omeprazole be taken?
• Omeprazole and levothyroxine comparison

Omeprazole and levothyroxine are two of the most commonly prescribed drugs in the nation. Commonly known by its brand name, Prilosec, omeprazole cuts down stomach acid production. As a proton pump inhibitor (PPI), it provides relief from heartburn and promotes the healing of stomach ulcers. Levothyroxine is a thyroid hormone used to reverse and prevent the symptoms of underactive thyroid function (hypothyroidism). The conditions they treat are quite common, so it is no surprise that many people need both drugs.

It is okay to treat acid reflux and hypothyroidism with omeprazole and levothyroxine, but there is an important interaction between the drugs to be aware of. We’ll cover what you should know and how to safely take omeprazole and levothyroxine under your healthcare provider’s guidance. 

Can you take levothyroxine and omeprazole together?

Patients can take levothyroxine and omeprazole concurrently. In fact, they may need to. According to the American Thyroid Association, levothyroxine is the recommended thyroid hormone for the treatment of hypothyroidism and is included on most insurance plan formularies. Omeprazole is a PPI, the most effective drug class for gastroesophageal reflux disease (GERD) and gastric ulcers, and a drug that many insurance plans cover. At any of the usual doses of omeprazole, from 20–40 milligrams (mg) once or twice daily, taking levothyroxine at its typical doses of 50–200 mcg once daily should generally be okay.

Although it may be okay to take levothyroxine and omeprazole concurrently, there is an important interaction to know about. Many conditions and medications affect the absorption of levothyroxine, and problems can arise if the body has insufficient thyroid hormone. 

One variable that impacts levothyroxine absorption is stomach acidity. If there isn’t enough acid in the stomach, orally administered thyroid hormone may not be absorbed as well. The fear is that blood levels of thyroxine could then be inadequate. An observational study and a retrospective review both found that thyroid stimulating hormone (TSH) levels were higher in patients taking a PPI with their levothyroxine compared to those taking levothyroxine alone. This finding indicates that thyroid hormone levels were lower since they are inversely correlated with TSH.

Taking levothyroxine and omeprazole together

In essence, the two drugs have a negative interaction, but it’s not significant enough to forbid their concurrent use in most cases. One randomized study, albeit small, concluded that omeprazole at a dose of 20–40 mg daily did not meaningfully affect levothyroxine absorption. Nonetheless, it is important to be carefully monitored by a healthcare provider when taking both drugs. 

Ensuring proper thyroid hormone levels means checking TSH levels regularly. When levothyroxine therapy is begun or changed, this usually amounts to a TSH blood test every four to six weeks until the effective dose is determined. Likewise, healthcare providers may recommend checking TSH levels every four to six weeks when starting, increasing, or stopping omeprazole. Always let the healthcare provider managing your hypothyroidism know if you start taking omeprazole, whether you get it over the counter or are prescribed it by another healthcare provider. 

How far apart should levothyroxine and omeprazole be taken? 

The general recommendation is to take levothyroxine on an empty stomach and at least 30–60 minutes before breakfast since many foods can negatively impact its absorption. Supplements and other drugs can, too. Calcium, magnesium, iron, and antacids are common examples of pills that should not be taken at the same time as levothyroxine and may best be separated by four hours.

Omeprazole and other PPIs, including Nexium (esomeprazole), Prevacid (lansoprazole), and Protonix (pantoprazole), reduce stomach acid for 24 hours. In a study looking at 30 patients taking the PPI pantoprazole, the timing of the PPI dose did not change how much of an impact it had on levothyroxine therapy. As such, it’s not likely to matter whether someone takes omeprazole at the same time of day as levothyroxine or not. 

Omeprazole and levothyroxine comparison

In regard to their drug classes, their uses, and their side effects, omeprazole and levothyroxine are very different. Omeprazole reduces stomach acid, which helps with GERD and peptic ulcers, but less gastric acidity may increase the risk of infection or nutrient malabsorption. Levothyroxine provides thyroid hormone to correct hypothyroidism, but if it is not dosed and monitored appropriately, excess or insufficient thyroid hormone could result and cause hyperthyroidism or hypothyroidism symptoms.

Both drugs are generic, but brand-name formulations are available. Prilosec can be taken instead of omeprazole. Synthroid or Levoxyl can be substituted for levothyroxine. If you don’t have insurance that covers either drug, a SingleCare discount card or coupons can help you save over $170 on omeprazole and over $60 on levothyroxine.

*Cost at time of publication. Drug prices fluctuate and vary by location.

Bottom line

Omeprazole and levothyroxine can be taken together in most circumstances, probably without regard to whether they are taken at the same time of day or not. However, omeprazole does reduce the absorption of levothyroxine, which could impact the necessary dose. Ask your healthcare provider if taking the two drugs concurrently is safe for you and how monitoring thyroid hormone levels can help ensure that your dosing is optimized.