Pronunciation: fil-spah-ree
Generic name: sparsentan
Dosage form: oral tablet (200 mg, 400 mg)
Drug class: Miscellaneous cardiovascular agents

Medically reviewed by Carmen Pope, BPharm. Last updated on Mar 20, 2025.

What is Filspari?

Filspari is used to slow kidney function decline in adults with primary immunoglobulin A nephropathy (IgAN), who are at risk for their disease getting worse. It is a tablet that is taken once a day.

Filspari is only available through the Filspari REMS Program and it will be provided to you by a certified pharmacy. Before you begin treatment, you must read and agree to all of the instructions in the Filspari REMS Program. Your healthcare provider will give you all the details.

Filspari (sparsentan) gained full FDA approval on September 5, 2024, based on positive long-term confirmatory results from the PROTECT Study.

• Previously it had been under the accelerated approval designation since February 2023.

Mechanism

Filspari (sparsentan) works as a dual endothelin and angiotensin II receptor antagonist. It blocks both endothelin-1 and angiotensin II pathways, reducing protein in the urine and kidney inflammation while helping maintain blood pressure.

• These pathways are thought to contribute to kidney function decline in IgAN.
• This dual mechanism protects kidney function in patients with IgA nephropathy more effectively than single-pathway treatments.

Filspari belongs to the drug class called endothelin and angiotensin II receptor antagonists.

Side effects

The most common side effects of Filspari are:

• swelling of hands, legs, ankles and feet (peripheral edema)
• low red blood cells (anemia)
• dizziness.

Serious side effects and warnings

Filspari can cause serious side effects, including:

• Liver problems. Filspari can cause changes in liver tests. Liver failure was not observed in people treated with Filspari in clinical studies, but some medicines that are like Filspari can cause liver failure. Your healthcare provider will do blood tests to check your liver before starting treatment with Filspari, monthly for the first 12 months, then every 3 months during treatment. Your healthcare provider may temporarily stop or permanently stop treatment with Filspari if you have changes in your liver tests. Stop taking Filspari and get medical help right away if you develop any of the following signs of liver problems during treatment with Filspari:
  • nausea or vomiting
  • pain on the upper right side of your stomach area
  • tiredness
  • loss of appetite
  • yellowing of your skin or the white part of your eyes (jaundice)
  • dark “tea-colored” urine
  • fever
  • itching.
• Serious birth defects. Filspari can cause serious birth defects if taken during pregnancy. Patients who can become pregnant must not be pregnant when they start taking Filspari or become pregnant during treatment with Filspari or for 1 month after stopping treatment with Filspari. Patients who can become pregnant must have a negative pregnancy test before starting Filspari and must have a monthly negative pregnancy test during treatment and 1 month after stopping treatment with Filspari.
• Low blood pressure. Low blood pressure is common during treatment with Filspari and can also be serious. Tell your healthcare provider if you feel dizzy, light-headed, or faint. Stay hydrated during treatment.
• Worsening of kidney function. Your healthcare provider will check your kidney function during treatment with Filspari.
• Increased potassium in your blood. This is common during treatment with Filspari and can also be serious. Your healthcare provider will check your potassium blood level during treatment.
• Fluid retention. Filspari can cause your body to hold too much water. Tell your healthcare provider right away if you have any unusual weight gain or swelling of your ankles or legs.

It is not known if Filspari is safe and effective in children.

These are not all the possible side effects of Filspari. Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.

Related/similar drugs

Before taking

Before taking Filspari, tell your healthcare provider about all of your medical conditions, including if you:

• have liver problems
• are pregnant or plan to become pregnant
• are breastfeeding or plan to breastfeed.

Pregnancy

Filspari can cause serious birth defects. Patients who can become pregnant must not be pregnant when they start taking Filspari or become pregnant during treatment with Filspari or for 1 month after stopping treatment with Filspari.

Patients who can become pregnant must have a negative pregnancy test before starting Filspari and must have a monthly negative pregnancy test during treatment and 1 month after stopping treatment with Filspari.

Patients who can become pregnant are those who:

• have entered puberty, even if they have not started their menstrual period, and
• have a uterus, and have not gone through menopause. Menopause means that you have not had a menstrual period for at least 12 months for natural reasons, or that you have had your ovaries removed.

Patients who cannot become pregnant are those who:

• have not yet entered puberty, or
• do not have a uterus, or
• have gone through menopause. Menopause means that you have not had a menstrual period for at least 12 months for natural reasons, or that you have had your ovaries removed, or are infertile for any other medical reason and this infertility is permanent and cannot be reversed.

Patients who can become pregnant must use effective birth control before starting treatment with Filspari, during treatment with Filspari, and for 1 month after stopping Filspari because the medicine may still be in your body.

If you have had a tubal sterilization or have an IUD (intrauterine device) or progesterone implant, these methods may be used alone, and no other form of birth control is needed.

Talk with your healthcare provider or gynecologist (a healthcare provider who specializes in reproduction) to find out about options for effective forms of birth control that you may use to prevent pregnancy during treatment with Filspari.

If you decide that you want to change the form of birth control that you use, talk with your healthcare provider or gynecologist to be sure that you choose another effective form of birth control.

See the Filspari Package Insert for acceptable birth control options during treatment with Filspari. Do not have unprotected sex. Talk to your healthcare provider or pharmacist right away if you have unprotected sex or if you think your birth control has failed. Your healthcare provider may talk with you about using emergency birth control.

Tell your healthcare provider right away if you miss a menstrual period or think you may be pregnant.

Breastfeeding

It is not known if Filspari passes into your breast milk. Do not breastfeed during treatment with Filspari. Talk to your healthcare provider about the best way to feed your baby during treatment with Filspari.

How do I take Filspari?

Take Filspari exactly as your healthcare provider tells you to take it. Do not stop taking Filspari unless your healthcare provider tells you.

• Filspari is a tablet that is taken once a day.
• Swallow the tablet whole with water before your morning or evening meal. Do not crush break or chew the tablet. Take your dose before the same meal each day.
• If you take an antacid, take Filspari 2 hours before or 2 hours after you take your antacid.

Before starting treatment with Filspari, your healthcare provider may discontinue some medications, such as angiotensin receptor blockers, ERAs or aliskiren.

Dosing information

• Initial dose: Filspari 200 mg once daily
• After 14 days: Increase the dose to 400 mg once daily as tolerated.

When resuming Filspari after an interruption, consider re-titration.

Available as 200 mg and 400 mg tablets

What happens if I miss a dose?

If you miss a dose, take the next dose at the regularly scheduled time. Do not take 2 doses at the same time or take extra doses.

What happens if I overdose?

 If you take too much Filspari, call your healthcare provider or go to the nearest hospital emergency room right away.

What other medications affect Filspari?

Tell your healthcare provider about all the medicines you take, including prescription and over-the-counter medicines, vitamins, herbal supplements, and grapefruit. Filspari and other medicines may affect each other and cause side effects. Do not start any new medicine until you check with your healthcare provider.

Especially tell your healthcare provider if you take:

• nonsteroidal anti-inflammatory drugs (NSAIDs)
• potassium-containing medicines, potassium supplements, or salt substitutes containing potassium
• blood pressure medicines
• H2 receptor blocker medicine or proton pump inhibitor (PPI) medicine.

Ask your healthcare provider or pharmacist if you are not sure if you take one of these medicines.

How should I store Filspari?

Store at room temperature between 68°F to 77°F (20°C to 25°C).

Store in the original container. The bottle has a child-resistant closure.

Keep out of the reach of children.

What are the ingredients in Filspari?

Active ingredient: sparsentan

Inactive ingredients: colloidal silicon dioxide, lactose anhydrous, magnesium stearate, silicified microcrystalline cellulose, and sodium starch glycolate. Tablets are film coated with material containing macrogol/polyethylene glycol, polyvinyl alcohol-partially hydrolyzed, talc, and titanium dioxide.

Who makes Filspari?

Filspari (sparsentan) is manufactured by Travere Therapeutics, a biopharmaceutical company headquartered in San Diego, California.

Travere Therapeutics (formerly known as Retrophin) focuses on developing treatments for rare diseases and has a particular emphasis on kidney and liver disorders.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Medical Disclaimer