Tamiflu (oseltamivir phosphate) is prescribed to treat or help prevent the flu. This drug can interact with other medications and certain vaccines. For example, Tamiflu can interact with probenecid and the intranasal flu vaccine.
Tamiflu is used in adults and certain children to:
- treat flu, when you’ve had flu symptoms no more than 48 hours (2 days)
- help prevent flu, to be used within 48 hours after close contact with someone who has the flu or to be used during a community flu outbreak
An interaction can occur because one substance causes another substance to have a different effect than expected. Interactions also can occur if you have certain health conditions.
Tamiflu contains the active ingredient oseltamivir phosphate. Tamiflu comes as an oral capsule and an oral liquid suspension (type of mixture). Interactions are expected to be the same with both forms.
Keep reading to learn about Tamiflu’s possible interactions. And for more information about Tamiflu, including details about its uses, see this article.
Before you start taking Tamiflu, tell your doctor and pharmacist about any prescription, over-the-counter, or other drugs you take. Sharing this information with them may help prevent possible interactions. (To learn whether Tamiflu interacts with herbs or vitamins and supplements, see the “Are there other interactions with Tamiflu?” section.)
If you have questions about drug interactions that may affect you, talk with your doctor or pharmacist.
The table below lists drugs that may interact with Tamiflu. Keep in mind that this table does not include all drugs that may interact with Tamiflu. For more information about these interactions, see the “Drug interactions explained” section.
Drug name | What can happen |
---|---|
dichlorphenamide (Keveyis, Ormalvi) | can increase the risk of side effects from Tamiflu |
probenecid (Probalan) | can increase the risk of side effects from Tamiflu |
Certain health conditions or other factors could raise your risk of harm if you take Tamiflu. In such cases, your doctor may not prescribe Tamiflu for you. These are known as contraindications. Below is a contraindication of Tamiflu.
If you’ve had an allergic reaction: If you’ve had an allergic reaction to Tamiflu or any of its ingredients, your doctor likely won’t prescribe Tamiflu for you. This is because taking the drug could cause another allergic reaction. You can ask your doctor about other treatments that may be better options for you.
Before you start taking Tamiflu, talk with your doctor if any of the factors above apply to you. Your doctor can determine whether Tamiflu is safe for you to take.
Tamiflu is not known to interact with alcohol.
But drinking alcohol can affect your immune system. This may make it harder for your body to clear an infection, including the flu. (Tamiflu is prescribed to treat and help prevent flu infection.) So your doctor may advise you to minimize or avoid drinking alcohol until your infection is cleared.
If you have questions about consuming alcohol during Tamiflu treatment, talk with your doctor or pharmacist.
Learn more about certain drug interactions that can occur with Tamiflu.
Interaction with dichlorphenamide
Tamiflu can interact with dichlorphenamide (Keveyis, Ormalvi). This drug treats primary periodic paralysis, including hypokalemic periodic paralysis and similar other conditions. Dichlorphenamide belongs to a drug class called carbonic anhydrase inhibitors.
What could happen
Taking Tamiflu with dichlorphenamide can raise your risk of Tamiflu side effects, such as nausea and vomiting. This is possible because dichlorphenamide can increase the level of Tamiflu in your body.
What you can do
If you take dichlorphenamide, your doctor will likely prescribe another treatment for the flu besides Tamiflu. At times, Tamiflu is the best or only option for treating your flu infection. In this case, your doctor will monitor you closely for side effects of Tamiflu.
If you have questions about taking Tamiflu with dichlorphenamide, talk with your doctor or pharmacist.
Interaction with probenecid
Tamiflu can interact with probenecid (Probalan), which is used to treat gout.
What could happen
Taking Tamiflu and probenecid can increase your risk of Tamiflu side effects, including headache and vomiting. This interaction occurs because probenecid can increase the level of Tamiflu in your body. Specifically, probenecid can decrease how well your kidneys remove Tamiflu from your body.
What you can do
It’s typically safe to take probenecid and Tamiflu together, as this interaction is not considered severe. But your doctor may monitor you closely for side effects from Tamiflu.
If you have a kidney condition, your risk of Tamiflu side effects due to this interaction may increase. As a result, your doctor may prescribe a flu treatment other than Tamiflu. Or they may prescribe Tamiflu and monitor you closely for side effects.
Tamiflu may have other interactions. They could occur with supplements, foods, vaccines, or even lab tests. See below for details. Note that the information below does not include all other interactions possible with Tamiflu.
Does Tamiflu interact with supplements?
Before you start taking Tamiflu, talk with your doctor and pharmacist about any herbs or vitamins and supplements you take. Sharing this information with them may help you avoid possible interactions.
If you have questions about interactions that may affect you, talk with your doctor or pharmacist.
Tamiflu and herbs
Tamiflu currently has no reports of interacting with herbs. But this doesn’t mean that interactions with herbs won’t be recognized in the future.
For this reason, it’s still important to check with your doctor or pharmacist before taking any of these products while taking Tamiflu.
Tamiflu and vitamins
Tamiflu currently has no reports of interacting with vitamins. But this doesn’t mean that vitamin interactions won’t be recognized in the future.
For this reason, it’s still important to check with your doctor or pharmacist before taking any of these products while using Tamiflu.
Does Tamiflu interact with food?
Tamiflu currently has no reports of interacting with food. If you have questions about eating certain foods during your treatment with Tamiflu, talk with your doctor.
Does Tamiflu interact with vaccines?
Tamiflu can interact with the intranasal flu vaccine, which is used to help prevent flu.
Tamiflu can cause the intranasal flu vaccine to not work. The intranasal flu vaccine is a live vaccine. This means it contains a weakened version of the bacteria or virus that it’s meant to protect against. Because Tamiflu works to treat flu infection, it can destroy the virus in the intranasal flu vaccine.
To avoid this interaction, the drugmaker recommends specific timing of the intranasal flu vaccine around Tamiflu treatment. That is, avoid receiving the vaccine for at least 48 hours after your last Tamiflu dose. And within 2 weeks after getting the vaccine, avoid Tamiflu unless it’s the best or only way to treat your infection.
On the other hand, Tamiflu and an inactivated flu vaccine (such as the flu shot) will not interact. You should be able to receive an inactivated flu vaccine at any time before, during, or after Tamiflu treatment. Inactivated vaccines contain a killed version of the bacteria or virus they’re meant to protect against. This means the killed virus or bacteria cannot cause infection.
If you have questions about getting certain vaccines during your Tamiflu treatment, talk with your doctor.
Does Tamiflu interact with lab tests?
Tamiflu currently has no reports of interacting with lab tests. If you have questions about having certain lab tests during your treatment with Tamiflu, talk with the healthcare professional ordering the test.
Does Tamiflu interact with cannabis or CBD?Tamiflu currently has no reports of interacting with cannabis (commonly called marijuana) or cannabis products such as cannabidiol (CBD). But as with any drug or supplement, talk with your doctor before using cannabis with Tamiflu.
Note: Cannabis is illegal at a federal level but is legal in many states to varying degrees.
Certain medical conditions or other health factors may raise the risk of interactions with Tamiflu. Before taking Tamiflu, talk with your doctor about your health history. They’ll determine whether Tamiflu is right for you.
Health conditions or other factors that might interact with Tamiflu include:
Hereditary (genetic) fructose intolerance: Tamiflu oral suspension contains sorbitol, which may cause diarrhea and upset stomach in people with fructose intolerance. Tamiflu capsules do not contain sorbitol and are safe to use if you have fructose intolerance.
Kidney problems: Kidney problems, such as chronic kidney disease, can affect how well your body clears Tamiflu. If you have a kidney problem, levels of Tamiflu in your system could increase. This can raise your risk of side effects from Tamiflu, including headache and vomiting. Depending on the severity of your kidney problem, your doctor may prescribe a Tamiflu dosage that’s lower than usual. Or they may recommend a flu treatment other than Tamiflu that’s safer for you.
Severe liver problems: It’s not known whether Tamiflu is safe to take if you have a severe liver problem, such as cirrhosis. As a result, your doctor may suggest flu treatments other than Tamiflu. If you have a mild or moderate liver problem, Tamiflu is considered safe to use.
Pregnancy: It’s not known whether Tamiflu is safe to take during pregnancy. If you’re pregnant or planning a pregnancy, talk with your doctor before taking Tamiflu.
Breastfeeding: It’s not known whether it’s safe to take Tamiflu while breastfeeding. The drug passes into breast milk. But it isn’t known whether the drug may cause side effects in a child who’s breastfed. If you’re breastfeeding or planning to, talk with your doctor about your options.
Allergic reaction: If you’ve had an allergic reaction to Tamiflu or any of its ingredients, your doctor likely won’t prescribe Tamiflu. This is because taking the drug could cause another allergic reaction. You can ask your doctor about other treatments that may be better choices for you.
Taking certain steps can help you avoid interactions with Tamiflu. Before starting treatment, talk with your doctor and pharmacist. Things to discuss with them include:
- whether you drink alcohol or use cannabis
- other medications you take, as well as any vitamins, supplements, and herbs (they can also help you fill out a medication list)
- what to do if you start taking a new drug during your Tamiflu treatment
It’s also important to understand Tamiflu’s
If you have trouble reading or understanding this information, your doctor or pharmacist can help.
Taking Tamiflu exactly as prescribed can also help prevent interactions.
Disclaimer: Healthline 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.