7 Dexamethasone Interactions You Should Know About

Dexamethasone is a common corticosteroid medication. Found at both community pharmacies and hospitals, it can help calm an overactive immune system. It can also relieve uncomfortable symptoms of inflammation (swelling). Conditions like skin rashes, allergic reactions, and respiratory problems may benefit from dexamethasone if and when it’s needed.

Corticosteroids like dexamethasone can come in handy, but they also interact with several medications, vaccines, and foods. Even though dexamethasone is often only used for a short period of time, it’s important to know about several possible interactions before taking it. We’ll discuss a few of them below.

1. Warfarin

Warfarin (Coumadin, Jantoven) is a blood thinner that helps treat and prevent blood clots. However, many medications and foods can make it more or less effective. People who take warfarin often have their blood monitored to make sure it isn’t too thick or thin.

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Dexamethasone can change how well warfarin works. Some studies show that it can enhance warfarin’s effects. This may cause your blood to become too thin, which can increase your risk of dangerous bleeding and/or bruising. Other studies show that dexamethasone can make warfarin less effective, making it more likely to experience a blood clot. 

In other words, dexamethasone may affect warfarin in different ways. If you need to take these medications together, your healthcare provider may want to check your blood work more often. They may also want to adjust your warfarin dosage while taking dexamethasone.

2. Certain diabetes medications

Corticosteroids, like dexamethasone, can raise your blood sugar. This is true even if you only take them for just a few days. If you have diabetes and take medications to control your blood sugar, dexamethasone makes it harder for these medications to be effective. This can make your blood sugar go up.

These are some common diabetes medications that can interact with dexamethasone:

• Metformin

• Insulin

• Sulfonylureas like glipizide 

• Thiazolidinediones like pioglitazone (Actos) 

• DPP-4 inhibitors like sitagliptin (Januvia) 

• GLP-1 agonists like dulaglutide (Trulicity)

• SGLT2 inhibitors like canagliflozin (Invokana)

If you’re taking a blood sugar-lowering medication and begin taking dexamethasone, be sure to let your healthcare provider know. Your healthcare provider may need to adjust your medication dosages while you’re taking dexamethasone. This could help prevent episodes of hyperglycemia (high blood sugar levels). 

It’s also a good idea to check your blood sugar more often while taking dexamethasone. Make sure to look out for hyperglycemia symptoms, like being thirstier than usual or needing to urinate more often.

3. NSAIDs

Nonsteroidal anti-inflammatory drugs (NSAIDs) are common medications that relieve pain and swelling. Some are available over the counter, and others are available with a prescription. But if they’re used too frequently — especially at high doses — they may cause stomach irritation or damage. Common NSAIDs include:

• Aspirin

• Ibuprofen (Advil, Motrin)

• Naproxen (Aleve, Naprosyn)

• Meloxicam (Mobic)

• Ketorolac 

• Indomethacin (Indocin)

• Diclofenac

• Piroxicam (Feldene)

Dexamethasone can also cause stomach irritation. This includes stomach ulcers and bleeding. If you combine dexamethasone and an NSAID, there’s a higher risk of stomach problems. 

To lower the risk of stomach irritation, it’s best to take dexamethasone with food. And if you need to take both medications, try to avoid taking them at the same time of day. This can help prevent excessive stomach irritation. Make sure to also watch out for signs of stomach bleeding or stomach ulcers. This may include symptoms like dark or bloody stools, stomach pain that’s worse after eating, and bloody vomit.

4. Antifungals like ketoconazole

Ketoconazole is an antifungal medication. It slows the growth of certain fungi that cause infection. It's a strong antifungal, too; it’s usually only used if other antifungals haven’t worked. 

Antifungals like ketoconazole block the effects of certain liver enzymes (proteins) that break down dexamethasone in your body. When this happens, dexamethasone lingers in your body for longer than it should. This can lead to higher dexamethasone levels, which may cause more severe side effects.

Like ketoconazole, these antifungals have a similar effect on dexamethasone:

• Fluconazole (Diflucan)

• Voriconazole (Vfend)

• Posaconazole (Noxafil)

• Isavuconazonium (Cresemba)

• Itraconazole (Sporanox)

If you can avoid combining dexamethasone with these medications, that’s ideal. But if you need to take them together, keep an eye out for dexamethasone side effects. This may include swelling in the hands and feet, insomnia, and stomach irritation.

5. Phenytoin

Phenytoin (Dilantin, Phenytek) is a medication that treats certain types of seizures. But it interacts with many medications, including dexamethasone.

Dexamethasone can affect phenytoin levels in your body. They can become higher or lower. This can lead to more phenytoin side effects — such as drowsiness and involuntary eye movements — or worse seizure control. Phenytoin can also lower levels of dexamethasone in your body, making it less effective. 

This interaction can cause unpredictable effects in your body. It's not entirely understood why this happens. As a precaution, your healthcare provider may check your phenytoin levels more often while taking dexamethasone. They may also adjust your dosage of one or both medications.

6. Live vaccines

Dexamethasone reduces inflammation in the body. It does this by quieting your immune system. But in order for live vaccines to be as effective as possible, your immune system should be as active as it can.

When dexamethasone suppresses your immune system, live vaccines may not work as well as they should. As a result, they may offer less protection against the illness they’re looking to prevent. Common live vaccine examples include:

• Measles, mumps, and rubella (MMR)

• Chickenpox (ProQuad, Varivax) 

• Rotavirus (Rotarix, RotaTeq)

• Yellow fever (YF-Vax)

This interaction is usually only a problem if you take dexamethasone for 2 weeks or longer, especially at high doses. If you’ve been taking it for longer than 2 weeks, it’s recommended to wait at least 1 month before receiving any live vaccines. But to play it safe, your healthcare provider may want to defer live vaccination — even if you’ve taken dexamethasone for less than 2 weeks. 

7. Alcohol

Alcohol and dexamethasone can both irritate your stomach on their own. And when you take them together, this risk is even higher. Because of this, it's best to avoid drinking alcohol while taking dexamethasone. This helps lower your risk of stomach problems. 

In addition to this, combining the two can increase your risk of infection and mood changes. Your healthcare provider can tell you more about the risk of combining alcohol and dexamethasone.

When should I contact my healthcare provider about a dexamethasone interaction?

Before you take dexamethasone, make sure your healthcare provider and pharmacist have an updated list of all medications you take. This list should include any medications, dietary supplements, and herbal products. This helps them make sure it's safe for you to take dexamethasone. 

If you have any questions or concerns about a dexamethasone interaction — or symptoms you’re experiencing — don’t hesitate to ask your healthcare provider or pharmacist. But if your symptoms feel severe, seek medical attention right away. 

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Written by:

Sonja Jacobsen, PharmD, BCPS, BCOP

Sonja Jacobsen, PharmD, BCPS, BCOP,  is a clinical oncology pharmacy specialist currently practicing in Seattle. She has been practicing as a pharmacist since 2015 and is licensed to practice in Washington state and North Carolina.

Edited by:

Joshua Murdock, PharmD, BCBBS

Joshua Murdock, PharmD, BCBBS, is a licensed pharmacist in Arizona, Colorado, and Rhode Island. He has worked in the pharmacy industry for more than 10 years and currently serves as a pharmacy editor for GoodRx.

Reviewed by:

Stacia Woodcock, PharmD

Stacia Woodcock, PharmD, is a pharmacy editor for GoodRx. She earned her Doctor of Pharmacy degree from the University of Kentucky and is licensed in New York and Massachusetts.

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