Tamiflu (oseltamivir) is a brand-name oral capsule and oral suspension. It’s an antiviral prescribed for the flu in certain adults and children. Tamiflu has interactions with some other drugs and the nasal spray flu vaccine.
An interaction occurs when one substance causes another substance to have a different effect than expected.
To learn more about Tamiflu’s interactions, keep reading. For additional information about Tamiflu, including details about its uses, see this article.
Before you start treatment with Tamiflu, tell your doctor and pharmacist which prescription, over-the-counter, and other medications you take. By sharing this information with them, you may help prevent possible interactions. (To learn whether Tamiflu interacts with supplements, herbs, or vitamins, see the “Tamiflu and other interactions” section below.)
If you have questions about drug interactions that may affect you, ask your doctor or pharmacist.
Here’s a table of drugs that can interact with Tamiflu. Keep in mind that this table doesn’t include all drugs that may interact with Tamiflu. Some of these interactions are described in detail just below in “Drug interactions in depth.”
| Drug class or drug name | Drug examples | Interaction result with Tamiflu |
| dichlorphenamide and drugs that contain it | • dichlorphenamide (Keveyis, Ormalvi) | can increase the risk of side effects of Tamiflu |
| probenecid and drugs that contain it | • probenecid (Probalan) • colchicine/probenecid (Col-Probenecid) | can increase the risk of side effects of Tamiflu |
In some cases, factors or conditions could prevent your doctor from prescribing Tamiflu due to the risk of harm. These are known as contraindications. Below are the Tamiflu contraindications to consider:
Having had an allergic reaction to Tamiflu or any of its ingredients
If you have had an allergic reaction to Tamiflu or any of its ingredients, your doctor will likely not prescribe Tamiflu. Taking the drug could cause another allergic reaction. You can ask them about other treatments that may be better choices for you.
Note: Before you start treatment with Tamiflu, it’s important to tell your doctor if this contraindication applies to you. They can determine whether to prescribe Tamiflu.
There are no known interactions between Tamiflu and alcohol.
However, alcohol can also worsen flu symptoms such as headache and fatigue. (Tamiflu is prescribed to treat and help prevent the flu). These symptoms may be worsened if you consume alcohol during Tamiflu treatment.
If you have questions about drinking alcohol while taking Tamiflu, talk with your doctor.
Here’s a closer look at certain drug interactions of Tamiflu.
Dichlorphenamide
Dichlorphenamide (Keveyis, Ormalvi) is prescribed to treat certain types of paralysis.
Interaction result: Taking Tamiflu with dichlorphenamide may increase the risk of side effects from Tamiflu.
Interaction explained: Dichlorphenamide may block the activity of a specific protein that helps move Tamiflu through your body after taking a dose. This effect can result in a high level of Tamiflu in your system, increasing your risk of side effects from the drug.
Steps you or your doctor may take: Before taking Tamiflu with dichlorphenamide, talk with your doctor. They can advise whether it’s safe to take these medications together or if a different antiviral may be prescribed instead of Tamiflu.
To learn more about Tamiflu and dichlorphenamide, talk with your doctor or pharmacist.
Probenecid
Probenecid is prescribed to treat gout. It may be prescribed alone (brand name Probalan) or in combination with colchicine (brand name Col-Probenecid).
Interaction result: Taking Tamiflu with probenecid may increase the risk of Tamiflu’s side effects.
Interaction explained: Probenecid can affect your kidneys’ ability to remove Tamiflu from your system. This can lead to a high level of Tamiflu in your body, which may increase your risk of side effects from the drug.
Steps you or your doctor may take: Talk with your doctor before taking Tamiflu with probenecid. They can recommend whether it’s safe to take these medications together. If needed, they may prescribe a different antiviral instead of Tamiflu.
To learn more about Tamiflu and probenecid, talk with your doctor or pharmacist.
Tamiflu may have other interactions, such as with supplements, foods, vaccines, or even lab tests. You’ll find details below. Keep in mind that the following information does not include all other possible interactions with Tamiflu.
Tamiflu and supplements
It’s possible for drugs to interact with supplements such as vitamins and herbs.
Tamiflu and herbs
There are no specific reports of herbs interacting with Tamiflu. However, that doesn’t mean herbal interactions won’t occur or be recognized in the future. Because of this, it’s important to check with your doctor or pharmacist before taking any of these products during Tamiflu treatment.
Tamiflu and vitamins
There are no specific reports of vitamins interacting with Tamiflu. However, that doesn’t mean vitamin interactions won’t occur or be recognized in the future. Because of this, you should talk with your doctor or pharmacist before taking any vitamin product with Tamiflu.
Tamiflu and food
There were no reports of food interactions with Tamiflu. If you’d like to learn more about eating certain foods during treatment with Tamiflu, talk with your doctor.
Tamiflu interactions with vaccines
Tamiflu may interact with the nasal spray flu vaccine (FluMist, FluMist Quad). This is a live flu vaccine, meaning it contains weakened pieces of the flu virus.
Tamiflu works by fighting against the flu virus. So the live flu vaccine may not work as well if you receive it during Tamiflu treatment.
Before starting Tamiflu, talk with your doctor or pharmacist about any vaccines you may need. If you need a flu vaccine, they may give you the injectable form (flu shot) instead. Alternatively, they may advise you to wait until at least 48 hours after your last Tamiflu dose before getting the nasal spray flu vaccine.
To learn more about Tamiflu and the nasal spray flu vaccine, talk with your doctor or pharmacist.
Tamiflu and lab tests
Tamiflu isn’t known to interact with any lab tests. If you have concerns about this medication interacting with lab tests, talk to your doctor.
TAMIFLU AND CANNABIS OR CBDCannabis (often called marijuana) and cannabis products, such as cannabidiol (CBD), have not been reported to interact with Tamiflu. However, as with any drug or supplement, talk with your doctor before using cannabis in combination with Tamiflu. The effect of cannabis may affect how well you stick to your Tamiflu treatment plan.
Note: Cannabis is illegal at a federal level but is legal in many states to varying degrees.
Certain medical conditions and other factors may increase the risk of interactions with Tamiflu. Before you take this drug, be sure to talk with your doctor about your health history. Tamiflu may not be the right treatment option if you have certain medical conditions or other factors affecting your health.
Health conditions or factors that might interact with Tamiflu include:
Kidney problems: If you have a kidney problem, such as kidney failure, talk with your doctor before taking Tamiflu. This condition may increase your risk of side effects from the drug. To reduce this risk, your doctor may prescribe a lower Tamiflu dosage than usual.
Fructose intolerance: If you have an inherited form of fructose intolerance, your doctor may not prescribe the oral suspension form of Tamiflu. This form of Tamiflu contains sorbitol (a type of sweetener), which may cause diarrhea or indigestion for people with this condition.
Your doctor may prescribe the oral capsule form of Tamiflu instead. If you have trouble swallowing capsules, you can open the Tamiflu capsules and mix their contents with sweetened liquids. Examples include corn syrup and chocolate syrup.
Allergic reaction: If you’ve had an allergic reaction to Tamiflu or any of its ingredients, your doctor will likely not prescribe Tamiflu. Taking the drug could cause another allergic reaction. You can ask them about other treatments that may be better choices for you.
Breastfeeding: It’s not known whether it’s safe to take Tamiflu while breastfeeding. The drug passes into breast milk. However, reports of the drug’s use while breastfeeding have not shown any harmful effects on a child who is breastfed. If you’re breastfeeding or planning to, talk with your doctor before using Tamiflu. They can talk with you about treatment options and ways to feed your child.
Pregnancy: There haven’t been enough clinical trials to determine whether Tamiflu is safe to take while pregnant. However, reports of the drug’s use in pregnancy have not shown Tamiflu to cause any congenital anomalies (commonly known as birth defects). If you’re pregnant or planning to become pregnant, tell your doctor before starting Tamiflu. They can advise you on the right treatment plan for you.
You can take certain steps to help prevent interactions with Tamiflu. Your doctor and pharmacist are key resources, so reach out to them before starting treatment. For example, you should plan to do the following:
- Let them know if you drink alcohol or use cannabis.
- Tell them about any other medications you take, as well as any supplements, herbs, and vitamins.
- Create a
medication list , which your doctor and pharmacist can help you fill out.
It’s also important to read the Tamiflu label and other
If Tamiflu doesn’t come with paperwork, you can ask your pharmacist to print a copy. If you need help reading or understanding this information, ask your doctor or pharmacist.
You can also help prevent interactions with Tamiflu by taking it exactly as your doctor prescribes.
Disclaimer: Medical News Today has made every effort to make certain that all information is factually correct, comprehensive, and up to date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or another healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.