All About Filspari

What is Filspari used for?

Filspari is used in adults to help manage IgA nephropathy that is at risk of progressing. IgA nephropathy is a type of kidney disease.

Note: Filspari was first available in February 2023 via accelerated approval from the FDA. Accelerated approval is based on information from early clinical studies. As of September 2024, the FDA gave Filspari full approval for this use based on more studies becoming available.

IgA is a type of antibody, which is part of your immune system. Your kidneys remove waste from your body. But if you have IgA nephropathy, IgA builds up in your kidneys. This buildup causes the kidneys to filter your body’s waste less effectively. If your body isn’t able to rid itself of waste properly, it becomes inflamed. Your kidneys also become damaged, which may cause blood or protein to be excreted in your urine.

In people who have IgA nephropathy, two hormones may contribute to protein in the urine and kidney damage. These hormones are endothelin and angiotensin II. Filspari’s mechanism of action is to treat IgA nephropathy by blocking these two hormones. By blocking so, Filspari helps slow kidney damage. It also may reduce the amount of protein in your urine.

What are Filspari’s side effects?

Like most drugs, Filspari may cause mild to serious side effects. The lists below contain some of the more common side effects Filspari may cause, but they don’t include all side effects possible.

Keep in mind that side effects of a drug can depend on:

• your age
• your other health conditions
• other medications you take

Your doctor or pharmacist can tell you more about the potential side effects of Filspari. They also can suggest ways to help reduce side effects.

Mild side effects

Here’s a list of some of the mild side effects that Filspari can cause. To learn about other mild side effects, talk with your doctor or pharmacist or read Filspari’s prescribing information.

Mild side effects of Filspari that have been reported include:

• dizziness
• swelling in your hands, legs, ankles, or feet (known as peripheral edema)

Mild side effects of many drugs may go away within a few days to a couple of weeks. But if they become bothersome, talk with your doctor or pharmacist.

Serious side effects

Serious side effects from Filspari can occur, but they aren’t common. If you have serious side effects from Filspari, call your doctor right away. But if you think you’re having a medical emergency, you should call 911 or your local emergency number.

Serious side effects of Filspari that have been reported include:

• higher amounts of potassium in your blood than normal
• low blood pressure, including when you stand up too quickly
• anemia
• kidney function suddenly becoming worse (also called acute kidney injury or failure)
• boxed warnings:
  • risk of liver damage
  • risk of harm to a developing fetus

To learn more about the boxed warnings, see the “What should be considered before taking Filspari?” section.

ALLERGIC REACTION

For some people, Filspari can cause an allergic reaction. But this side effect wasn’t reported in the drug’s studies.

In general, symptoms of allergic reaction can be mild or serious.

What might help

If you have mild symptoms of an allergic reaction, such as a mild rash, call your doctor right away. They may suggest a treatment to manage your symptoms and can determine whether you should keep taking Filspari.

If you have symptoms of a severe allergic reaction, such as swelling or trouble breathing, call 911 right away. Or call your local emergency number. These symptoms could be life threatening and require immediate medical care.

Your doctor can confirm whether you’ve had a serious allergic reaction to Filspari. If so, they may have you switch to a different treatment.

Filspari cost and coupons

Whether or not you have health insurance, cost may be a factor when you’re considering Filspari. The price you’ll pay for Filspari may depend on several things. These include your treatment plan and the pharmacy you use.

Here are a few things to consider regarding cost:

• Cost information and savings coupons: You can visit Optum Perks to get price estimates for some medications when using coupons from the site. (Note: Optum Perks coupons cannot be used with any insurance copays or benefits.)
• Savings program: If you have questions about how to pay for your prescription, talk with your doctor or pharmacist. A program called Travere TotalCare also may be available.

You can also check out this article to learn more about saving money on prescriptions.

What are some frequently asked questions about Filspari?

Find answers to some commonly asked questions about Filspari.

How does Filspari compare vs. Tarpeyo?

Both Filspari and Tarpeyo (budesonide) are used to slow the progression of IgA nephropathy in certain situations. Both drugs are used only in adults. They belong to different groups of drugs.

Filspari comes as an oral tablet, while Tarpeyo is available as a delayed-release capsule. (“Delayed release” means the drug is released into your body slowly over time.) You typically take both drugs once daily.

If you have other questions about how Filspari and Tarpeyo compare, talk with your doctor. They can help you find the best treatment for your condition.

Will Filspari cure my IgA nephropathy?

No, Filspari does not cure IgA nephropathy. This condition currently has no cure. But Filspari works to help delay damage to your kidneys. It also may reduce the amount of protein in your urine. (You may have higher amounts of protein in your urine if you have IgA nephropathy.)

If you have other questions about what to expect from your Filspari treatment, talk with your doctor.

What is Filspari’s dosage?

Your doctor will recommend the dosage of Filspari that’s right for you. Below are commonly used dosages, but always take the dosage your doctor prescribes.

Form and strengths

Filspari is available as an oral tablet in two strengths: 200 milligrams (mg) and 400 mg.

Recommended dosages

To help manage IgA nephropathy that is at risk of progressing, your doctor will likely prescribe a starting dosage of 200 mg once daily. After 14 days, your doctor may increase your dosage to 400 mg once daily.

Before you start taking Filspari, your doctor will order blood tests. One will check your blood for certain levels of liver enzymes. The other is a test that checks your blood’s level of bilirubin. If these levels are higher than specific amounts, your doctor won’t prescribe Filspari.

Your doctor will continue to test your blood every month for the first 12 months you take Filspari. After that, you’ll have your blood tested every 3 months.

In certain situations, your doctor may choose to pause your Filspari treatment. One is if your liver enzymes again measure higher than specific amounts on one of these blood tests. Another is if you must take certain other medications. If either situation occurs, you may need to restart treatment with a dosage of 200 mg once daily. After that, your doctor may recommend returning you to a dosage of 400 mg once daily.

After pausing Filspari, some people might experience symptoms of liver damage. Or their liver enzymes don’t return to levels they had before treatment. In these cases, their doctor likely will choose to permanently stop the drug.

Questions about taking Filspari

Below are some common questions about taking Filspari.

• Can Filspari be chewed, crushed, or split? No, you should not chew, crush, or split Filspari tablets. You should swallow them whole with water. If you have trouble swallowing pills, check out this article or ask your doctor or pharmacist for advice.
• Should I take Filspari with food? You should take Filspari before you eat your morning or evening meal.
• Is there a best time of day to take Filspari? It’s best to take Filspari before you eat your morning or evening meal. But it’s also recommended to take it before the same meal each day. This helps keep a consistent level of the drug in your body, which helps Filspari work effectively.
• What if I miss a dose of Filspari? If you miss a dose of Filspari, take it as soon as you remember. But if it’s almost time to take your next dose, skip the missed dose. Then take your next dose at its usual time. You should not take two doses at once to make up for a missed dose. Doing so could raise your risk of side effects.
• Will I need to use Filspari long term? Filspari is typically used as a long-term treatment. You and your doctor can discuss whether it’s safe and effective for your condition. If you agree that it is, you’ll likely take it long term.
• How long does Filspari take to work? Filspari begins to work after you take your first dose. But you likely won’t feel the drug working in your body. Your doctor will order tests (such as kidney function and urine protein tests) throughout your treatment. This will help them check whether Filspari is working to treat your condition. After starting Filspari, 4 weeks later some people saw improvement in their lab test results. Talk with your doctor to learn more about what you can expect from your Filspari treatment.

Overdose

Do not take more Filspari than your doctor prescribes, as this can lead to harmful effects.

Symptoms of overdose

Symptoms caused by an overdose can include low blood pressure.

What to do in case you take too much Filspari

Call your doctor if you think you’ve taken too much Filspari. You can also call 800-222-1222 to reach America’s Poison Centers or use its online resource. But if you have severe symptoms, immediately call 911 or your local emergency number. Or go to the nearest emergency room.

What should be considered before taking Filspari?

Below is important information you should consider before taking Filspari.

Interactions

Taking a drug with certain medications, vaccines, foods, and other things can affect how the drug works. These effects are called interactions.

Filspari can interact with several other medications. It can also interact with certain supplements as well as certain foods.

Before starting Filspari treatment, talk with your doctor and pharmacist. Tell them about all prescription, over-the-counter, and other drugs you take. Also, tell them about any vitamins, herbs, and supplements you take. Sharing this information can help you avoid potential interactions.

If you have questions about drug interactions that may affect you, talk with your doctor or pharmacist.

Drug interactions

Below is a list of medications that can interact with Filspari. This list does not contain all drugs that may interact with Filspari. If you have questions about drug interactions that may affect you, ask your doctor or pharmacist.

Filspari and alcohol

In the drug’s studies, alcohol was not known to interact with Filspari. But Filspari does have a boxed warning about a risk of liver damage. Drinking large quantities of alcohol also may damage your liver. Talk with your doctor to determine whether it’s safe for you to consume alcohol during Filspari treatment.

Note: A boxed warning is the most serious warning from the FDA. For details, see the “What should be considered before taking Filspari?” section.

Other interactions

Filspari can interact with other substances such as:

• Vitamins or supplements: Filspari interacts with potassium supplements and St. John’s wort. Your doctor likely will recommend that you avoid taking these supplements during your Filspari treatment.
• Foods:
  • Filspari interacts with salt substitutes that contain potassium. During your Filspari treatment, your doctor likely will recommend that you not use salt substitutes containing potassium.
  • Filspari interacts with grapefruit and grapefruit juice. Your doctor likely will recommend that you not consume grapefruit products during your Filspari treatment.

Pregnancy and breastfeeding

Filspari is not safe to use during pregnancy or while breastfeeding.

Filspari has a boxed warning about risk to a developing fetus when the drug is taken in pregnancy. Due to this risk, your doctor likely will give you a pregnancy test before prescribing Filspari. They’ll likely have you repeat it every month that you take Filspari and 1 month after you stop taking the drug.

You’ll also need to take effective birth control if you’re able to become pregnant. (See the birth control section to learn more.)

Note: A boxed warning is the most serious warning from the FDA. For details, see the “What should be considered before taking Filspari?” section.

Birth control

It’s recommended that females who can become pregnant use birth control surrounding Filspari treatment. They should use it prior to treatment, during treatment, and for at least 1 month after taking the last dose.

Males with partners who can become pregnant should talk with a doctor to decide the best birth control option during their treatment. Travere Therapeutics (Filspari’s manufacturer) does not provide specific birth control recommendations for males in its prescribing information.

Note: In this article, we use the terms “male” and “female” to refer to someone’s sex assigned at birth. For information about the difference between sex and gender, see this article.

Boxed warnings

Filspari has boxed warnings about the risks of liver damage and harm to a developing fetus. A boxed warning is the most serious warning from the FDA about drug effects that may be dangerous.

The boxed warnings include:

Risk of liver damage: Taking Filspari may increase your risk of liver damage. Liver damage may range from increased liver enzymes to liver failure. Symptoms of liver damage include:

• nausea
• vomiting
• jaundice
• dark urine

If you think you’re experiencing any of these symptoms, stop taking Filspari and seek medical care right away.

Due to this risk, your doctor will check your liver enzyme and bilirubin levels before starting Filspari. They’ll continue rechecking them every month for the first 12 months of your treatment. After that, they’ll recheck them every 3 months. If your liver enzymes again measure higher than specific amounts at any point, your doctor may pause Filspari until the amounts lower. But in some cases, your doctor may stop the drug permanently.

Risk of harm to a developing fetus: Taking Filspari while pregnant may cause serious birth defects or pregnancy loss. Due to this risk, your doctor will have you take a pregnancy test at certain times. These times are before you start taking Filspari, each month of treatment, and 1 month after you stop taking the drug.

If you’re able to become pregnant, you’ll need to use effective birth control. Your doctor likely will recommend using it prior to treatment, during treatment, and for at least 1 month after taking your last dose.

Due to these risks, Filspari is available only through a risk evaluation and mitigation strategy (REMS) program. The FDA requires REMS programs for certain drugs to help make sure they’re given safely.

Talk with your doctor if you’d like to learn more about these boxed warnings.

Other warnings

Filspari can sometimes cause harmful effects in people who have certain conditions. This is known as a drug-condition interaction. Other factors also may affect whether Filspari is a good treatment option for you.

Talk with your doctor about your health history before you take Filspari. Be sure to tell them if any of the following factors apply to you:

• liver problems
• you take an ARB, endothelin receptor antagonist (ERA), or aliskiren
• problems with retaining more fluid than usual
• have or have had a sudden decline in kidney function
• higher amounts of potassium in your blood than normal
• heart problems
• past allergic reaction to Filspari
• pregnancy
• breastfeeding