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Tembexa

brincidofovir

Used for Smallpox

Tembexa (brincidofovir) is a newly-approved medication for the treatment of smallpox caused by the smallpox virus. Although the medication is convenient because it only requires two doses, it has many serious potential risks and side effects. Tembexa (brincidofovir) is FDA approved, but it's currently not available for use.

Reviewed by:

Robert Chad Hakim, PharmD, BCCCP

Kristianne Hannemann, PharmD

Last reviewed on September 27, 2022

Basics Side effects Pros & cons Pharmacist tips FAQs Warnings Dosage Alternatives Latest news Prices Medicare

What is Tembexa (brincidofovir)?

What is Tembexa (brincidofovir) used for?

Treatment of smallpox disease

How Tembexa (brincidofovir) works

Tembexa (brincidofovir) is an antiviral medication. It prevents the smallpox virus from making copies of itself and spreading in your body.

Are you looking for information on cidofovir instead?

Drug Facts

Common BrandsTembexa

Drug ClassAntiviral

Controlled Substance ClassificationNot a controlled medication

Generic StatusNo lower-cost generic available

AvailabilityPrescription only

What are the side effects of Tembexa (brincidofovir)?

The following side effects may get better over time as your body gets used to the medication. Let your healthcare provider know immediately if you continue to experience these symptoms or if they worsen over time.

Common Side Effects

There's no information about side effects when taken for smallpox treatment. Below are side effects reported in adults taking the tablets not specifically for smallpox.

Diarrhea (8%)
Nausea (5%)
Vomiting (4%)
Stomach pain (3%)

Other Side Effects

Low appetite
Muscle weakness
Change in taste
Rash

Serious Side Effects

Contact your healthcare provider immediately if you experience any of the following.

Liver problems: swelling of your stomach, yellowing of your skin or the whites of your eyes, confusion, dark or brown urine
Dehydration: dry mouth, not urinating as much, lightheadedness, dizziness
Cancer: signs or symptoms of cancer

Source: DailyMed

Pros and cons of Tembexa (brincidofovir)

Pros

Available as tablets and a lemon lime-flavored suspension

Total treatment is only two doses

Can be used in people of all ages

Cons

Has a lot of potentially serious risks, such as liver damage and cancer

Can't prevent smallpox disease; only used for treatment

Hasn't been studied in humans for the treatment of smallpox

Pharmacist tips for Tembexa (brincidofovir)

Take Tembexa (brincidofovir) exactly as prescribed. Never take extra doses or use Tembexa (brincidofovir) longer than prescribed. Doing so can cause serious harm.

Don't get the suspension or broken tablets on your skin or mucous membranes (e.g., inside of your nose). If this happens, wash the affected area well with soap and water. Rinse your eyes thoroughly with water if medication gets into your eyes.

Because of the risk of harm to babies, don't take Tembexa (brincidofovir) if you're pregnant. If you're able to get pregnant, use effective birth control during treatment with Tembexa (brincidofovir) and for at least 2 months after the last dose. If you're a male taking Tembexa (brincidofovir) and you have female partners of childbearing age, use condoms during treatment and for at least 4 months after the last dose.

While it isn't known if Tembexa (brincidofovir) can harm babies through breastfeeding, it's not recommended to breastfeed if you have smallpox. This is because the virus can pass through breast milk to babies.

Tembexa (brincidofovir) can interact with other medications, including erythromycin, rifampin, cyclosporine (Neoral, Sandimmune), and certain HIV and hepatitis C medications. Make sure to tell your provider about all of the medications you're taking before starting Tembexa (brincidofovir). You might have to switch certain medications or time how you take your medications (i.e., take them at least 3 hours after Tembexa (brincidofovir)). Don't start any new medications without talking to your provider or pharmacist first.

For the tablets only:

Take the tablets on an empty stomach or with a low-fat meal. If you choose to take it with food, ask your provider about what low-fat foods you can eat. Taking the medication with food might help relieve stomach side effects like diarrhea, nausea, vomiting, and stomach pain.

Swallow the tablets whole. Don't cut, break, or crush the tablets. If you're having trouble swallowing the tablets, ask your provider about the suspension.

For the suspension only:

Use an oral dosing syringe to measure your dose. Don't use household spoons, because they might not be accurate and cause you to take the wrong dose. Ask your pharmacy to provide you with an oral syringe if you don't have one.

Shake the bottle well before each use. Take the Tembexa (brincidofovir) suspension on an empty stomach to make sure it works best for you.

The suspension can be given through a feeding tube. First, flush the tube with water. Then, use a catheter-tip syringe with "mL" markings on it to measure the dose and give through the feeding tube. Refill the syringe with 3 mL of water, shake, and give the mixture through the tube. Then, flush the tube with water again to make sure all the medication has gone through.

Store the suspension at room temperature and keep it in its original bottle. Don't refrigerate or freeze the Tembexa (brincidofovir) suspension because this could damage the medication.

Frequently asked questions about Tembexa (brincidofovir)

Is Tembexa (brincidofovir) currently available?

Tembexa (brincidofovir) is not available at this time, even though the FDA approved the medication in 2021. Since its approval, the manufacturer of Tembexa (brincidofovir) received funding from a government program to make enough of the medication for possible public health emergency use. It's expected to be available in the near future. If you need treatment for smallpox right now, Tpoxx (tecovirimat) is an alternative medication that might be available to you. Ask your provider for more information about Tpoxx.

How well does Tembexa (brincidofovir) work?

Tembexa (brincidofovir)'s efficacy has only been studied in animals, not humans. Smallpox has been eradicated (no longer occurs naturally), so it would be unethical to infect humans just for the sake of the study. Animal studies showed that Tembexa (brincidofovir) prevented more deaths from smallpox-related viruses than placebo (sugar pill). Based on these results, researchers believe that Tembexa (brincidofovir) can potentially work against smallpox in humans.

Why is it important to take Tembexa (brincidofovir) if I have smallpox?

Smallpox is a contagious, long-lasting infection that has several stages. About 30% of people with smallpox can die from the infection. Those who survive can have permanent scars on their body (especially on the face), and others can become blind. Taking Tembexa (brincidofovir) might help stop the smallpox virus from making copies of itself so it can't spread.

Is Tembexa (brincidofovir) used to treat monkeypox?

Currently, Tembexa (brincidofovir) isn't FDA approved to treat monkeypox. There’s ongoing research studying whether Tembexa (brincidofovir) can be used for monkeypox since this virus is similar to smallpox. There isn't enough information to know if Tembexa (brincidofovir) works well against monkeypox in humans, but it shows some promise in animal studies. It's important to know that studies showed a higher risk of death in people taking Tembexa (brincidofovir) for a few months for a virus that wasn't the smallpox. Take Tembexa (brincidofovir) exactly as prescribed to make sure it's as safe for you as possible.

What tests will I need before starting Tembexa (brincidofovir)?

Because Tembexa (brincidofovir) can cause liver damage, your provider will order a blood test that checks your liver health before and during treatment. Additionally, if you're a female of childbearing age, you'll need to take a pregnancy test to make sure you're not pregnant before starting Tembexa (brincidofovir). This is because the medication can potentially cause harm to unborn babies.

Can I take Tembexa (brincidofovir) with food?

You can take the Tembexa (brincidofovir) tablets with a low-fat meal (about 400 calories, with about 25% of calories from fat) or on an empty stomach. Ask your provider about examples of low-fat meals that fit this criteria. On the other hand, you should take the suspension form on an empty stomach. This is because the effect of food on the suspension hasn't been studied, so it's not known if food lowers how much medication your body absorbs.

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What are the risks and warnings for Tembexa (brincidofovir)?

Tembexa (brincidofovir) can cause some serious health issues. This risk may be even higher for certain groups. If this worries you, talk to your doctor or pharmacist about other options.

Not for use other than smallpox

A higher risk for death is possible when Tembexa (brincidofovir) is taken longer than what's recommended for smallpox treatment. In studies involving a different viral infection (not smallpox), more deaths happened in people using Tembexa (brincidofovir) for a few months compared to those who didn't take this medication.

Take Tembexa (brincidofovir) exactly as prescribed for smallpox only. Don't take extra doses or use it longer than what's prescribed. This is to make sure Tembexa (brincidofovir) is as safe for you as possible.

Liver problems

Risk factors: History of liver problems

Tembexa (brincidofovir) can cause liver damage that can lead to serious liver problems. You'll need to get blood tests to check your liver health before and during treatment to make sure your liver is working properly. Seek medical attention right away if you notice swelling of your stomach, stomach pain, yellowing of your skin or the whites of your eyes, dark or brown urine, nausea, vomiting, or confusion. You might need to stop using the medication to prevent further liver damage.

Stomach side effects

Tembexa (brincidofovir) can cause diarrhea, nausea, vomiting, and stomach pain. Diarrhea and vomiting can lead to dehydration (e.g., dry mouth, not urinating as much, lightheadedness, dizziness). Contact your provider if you have these side effects after the first dose of Tembexa (brincidofovir). In some cases, your provider might tell you to stop taking the medication.

Not for use in pregnancy

There haven't been any human studies looking at how Tembexa (brincidofovir) affects pregnant females, so it's not completely known how safe it is. However, in animal studies, Tembexa (brincidofovir) caused significant harm to babies (e.g., development issues, death) when taken by mothers during pregnancy. Due to these findings, avoid the use of Tembexa (brincidofovir) in pregnant females, and find alternative treatment options. If you're a female of childbearing age, use birth control during treatment with Tembexa (brincidofovir) and for at least 2 months after your last dose. If you're a male taking Tembexa (brincidofovir) with female partners who can get pregnant, use condoms during treatment and for at least 4 months after your last dose.

Cancer

Tembexa (brincidofovir) can potentially cause cancer in humans. In animal studies, Tembexa (brincidofovir) caused certain types of cancer. To lower your risk for cancer, don't crush or cut the tablets. Also, don't let any broken tablets or the suspension to come into contact with your skin or mucous membranes (e.g., in your nose). If this happens, wash the affected area(s) well with soap and water. If your eyes came into contact with Tembexa (brincidofovir), rinse your eyes with water.

Male infertility

There isn't enough information to know if Tembexa (brincidofovir) can affect the ability to have children (fertility) in human males. But based on animal studies, Tembexa (brincidofovir) can potentially cause male infertility that can be permanent. This means it could be harder or impossible to have children. If you have concerns about this issue, speak to your provider.

Tembexa (brincidofovir) dosage forms

Typical dosing for Tembexa (brincidofovir)

Oral tablets: Each tablet contains 100 mg of brincidofovir.

Weigh 105 lbs or more: The typical dose is 200 mg by mouth once per week for 2 doses (on days 1 and 8).
Weigh less than 105 lbs: Don't use tablets. Use the suspension formulation of the medication.

Oral suspension: Each 5 mL (teaspoonful) contains 50 mg of brincidofovir.

Weigh 105 lbs (48 kg) or more: The typical dose is 20 mL (4 teaspoonfuls) by mouth once per week for 2 doses (on days 1 and 8).
Weigh 22 lbs (10 kg) to less than 105 lbs (48 kg): The typical dose is 4 mg/kg of body weight by mouth once per week for 2 doses (on days 1 and 8).
Weigh less than 22 lbs (10 kg): The typical dose is 6 mg/kg of body weight by mouth once per week for 2 doses (on days 1 and 8).

What are alternatives to Tembexa (brincidofovir)?

There are a number of medications that your doctor can prescribe in place of Tembexa (brincidofovir). Compare a few possible alternatives below.

Tembexa (brincidofovir)

Used for:

Treatment of smallpox disease

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Tpoxx (tecovirimat)