Filspari
Filspari (sparsentan) is a medication that works well to lower urine protein levels in people with immunoglobulin A nephropathy (IgAN). It's not known if this means Filspari (sparsentan) slows down worsening kidney function, but this is something that's currently being studied. Filspari (sparsentan) is taken by mouth, typically once daily. Some of the more common side effects it can cause include swelling in the arms and legs, low blood pressure, and dizziness.
What is Filspari (sparsentan)?
What is Filspari (sparsentan) used for?
- Lower urine protein levels in adults with immunoglobulin A nephropathy (IgAN)
How Filspari (sparsentan) works
Filspari (sparsentan) is an endothelin type A receptor blocker and an angiotensin II receptor blocker. It blocks two proteins which are thought to worsen IgAN (endothelin and angiotensin II) from binding to their receptors.
Drug facts
Side effects of Filspari (sparsentan)
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
- Swelling in arms or legs (14%)
- Low blood pressure (14%)
- Dizziness (13%)
- High blood potassium levels (13%)
Less Common Side Effects
- Low red blood cell count
- Kidney problems
- High liver enzymes
Filspari (sparsentan) serious side effects
Contact your healthcare provider immediately if you experience any of the following.
- Serious liver problems: swelling of your stomach, yellowing of your skin or the whites of your eyes, confusion, dark or brown urine
- Severely low blood pressure: dizziness, lightheadedness, feeling faint, tired, confusion
- Serious kidney problems: urinating less often than usual, swelling in your feet, ankles, or hands, unexplained weight gain
- High potassium levels: nausea, muscle weakness, abnormal heartbeat
The following Filspari (sparsentan) side effects have also been reported
Side effects that you should report to your care team as soon as possible:
- Allergic reactions—skin rash, itching, hives, swelling of the face, lips, tongue, or throat
- High potassium level—muscle weakness, fast or irregular heartbeat
- Kidney injury—decrease in the amount of urine, swelling of the ankles, hands, or feet
- Liver injury—right upper belly pain, loss of appetite, nausea, light-colored stool, dark yellow or brown urine, yellowing skin or eyes, unusual weakness or fatigue
- Low blood pressure—dizziness, feeling faint or lightheaded, blurry vision
- Low red blood cell level—unusual weakness or fatigue, dizziness, headache, trouble breathing
Side effects that usually do not require medical attention (report these to your care team if they continue or are bothersome):
- Dizziness
- Swelling of the ankles, hands, or feet
Pros and cons of Filspari (sparsentan)
Pros
- Works better at lowering urine protein levels than irbesartan (Avapro), an existing IgAN treatment option
- Taken by mouth
- Taken once daily
Cons
- More studies needed to show Filspari (sparsentan) can slow the worsening of kidney problems
- Not a cure for IgAN
- Can cause dangerously low blood pressure
- Not studied in children
Pharmacist tips for Filspari (sparsentan)
- Make sure to mark your appointments on your calendar for when you need to see your provider so they can monitor you while you're receiving Filspari (sparsentan). For examples, your provider will need to check your liver health monthly (during you first year of treatment), give you a monthly pregnancy test if you're able to become pregnant, and check your blood potassium level from time to time to make sure it's not too high.
- Take Filspari (sparsentan) with water before breakfast or dinner at the same time day every day. If you miss a dose, take the next dose at the regularly scheduled time and don't double or take extra doses to make up for the missed dose.
- There isn't a clearly defined length of time you need to take Filspari (sparsentan) because it isn't a cure for IgAN. Your provider will likely have you continue Filspari (sparsentan) treatment as long as it's working to keep your urine protein levels low and you're able to tolerate the side effects. Talk with your provider if you're not sure how long you need to receive Filspari (sparsentan) treatment.
- Filspari (sparsentan) interacts with a lot of commonly-used medications (prescription and over-the-counter), including angiotensin receptor blockers (ARBs), endothelin antagonists, and non-steroidal anti-inflammatory drugs (NSAIDs), among many others. Make sure to tell your provider about all of the medications you're taking before starting Filspari (sparsentan). Don't start any new medications without talking to your provider or pharmacist first to make sure the combination is safe to take.
- Be sure to drink enough fluids to stay hydrated while taking Filspari (sparsentan) because this can help prevent your blood pressure from dropping too low. But don't drink too much because Filspari (sparsentan) can also cause your body to hold onto too much fluid and swell up. If you're not sure how much is a safe amount of fluid to drink, ask your provider.
- If you're able to have children, it's recommended that you use birth control during treatment with Filspari (sparsentan) and for at least 1 month after your last dose. In addition, your provider will give you a pregnancy test before you start Filspari (sparsentan), monthly during your treatment, and a month after your last dose. Let your provider know right away if you get pregnant while taking this medication. Filspari (sparsentan) can potentially harm an unborn baby.
Common questions about Filspari (sparsentan)
IgAN, also called Berger's disease, is a kidney condition. It happens when proteins from your immune system (also known as antibodies) get stuck or trapped in the kidneys. This makes it very difficult for the kidneys to do their job, which is to filter and clean your blood. Your kidneys can then become inflamed and not work properly. Overtime, IgAN can lead to serious kidney problems. The most common signs of IgAN are bloody or dark-colored urine and foamy urine (which means there are high levels of protein in the urine).
One symptom of IgAN is having a lot of protein in the urine, which is a sign of kidney damage. A study looked at how well Filspari (sparsentan) worked at lowering the amount of protein in the urine compared to irbesartan (Avapro), an existing treatment option for IgAN. After about 9 months of treatment, results showed people taking Filspari (sparsentan) had about a 45% drop in the level of protein in the urine, compared to a 15% drop in people taking irbesartan (Avapro).
Since Filspari (sparsentan) can cause severe liver injury as well as severe harm to babies if taken by mothers during pregnancy, it's only available through a restricted program under a Risk Evaluation and Mitigation Strategy (REMS) called the Filspari REMS program. All providers who prescribe Filspari (sparsentan), pharmacies that dispense Filspari (sparsentan), and people who take Filspari (sparsentan) must be registered with the REMS program. This is to make sure the medication is distributed and taken under the safest conditions possible for you.
Studying a new medication usually takes many years. Sometimes, a medication can be approved in a shorter amount of time because it fills a medical need that isn’t currently met by other medications already available in the market. When the FDA approves a medication under an accelerated approval, the decision is based on a “marker” that suggests a clinical benefit (e.g., a medical condition improving). But in order for the medication to receive full approval, the manufacturer must prove the medication’s clinical benefit through additional studies at a later time. Filspari (sparsentan) got an accelerated approval after initial studies showed that it can lower urine protein levels in people with IgAN who are high risk for worsening kidney damage. But additional studies are needed to confirm whether or not having lower urine protein levels (the “marker”) actually slows the worsening of kidney problems.
Based on findings from animal studies, Filspari (sparsentan) can cause serious harm, including death, to babies if taken by mothers during pregnancy. If you're able to become pregnant, you should use birth control while taking Filspari (sparsentan) and for at least 1 month after your last dose. Additionally, there is no information on how safe Filspari (sparsentan) is during breastfeeding. But because there's a risk that this medication can pass into breastmilk and cause harm to breastfed babies, your provider will most likely recommend for you to avoid breastfeeding while taking Filspari (sparsentan). If you're pregnant, thinking of becoming pregnant, or breastfeeding, talk to your provider about the risks and benefits of continuing Filspari (sparsentan) treatment.
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Risks and warnings for Filspari (sparsentan)
Filspari (sparsentan) 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.
Serious liver damage
- Risk factors: History of liver problems | Taking other medications that can cause liver problems | Drinking large amounts of alcohol
Filspari (sparsentan) can cause serious liver problems that can lead to liver failure. Because of this risk, Filspari (sparsentan) is available only through the Filspari REMS program. You'll need to get blood tests to check your liver health before and during treatment to make sure your liver is working properly. Get medical attention right away if you notice symptoms of liver problems, such as swelling of your stomach, stomach pain, yellowing of your skin or the whites of your eyes, stool changes (black, tarry, or bloody stools), nausea, vomiting, confusion, or dark or brown urine. You might need to stop using the medication to prevent further liver damage.
Not for use during pregnancy
Filspari (sparsentan) shouldn't be taken during pregnancy. While it hasn't be studied in human pregnancy, animal studies show that it can cause severe and life-threatening harm to babies. If you're able to have children, your provider will ask you take a pregnancy test before you start Filspari (sparsentan), monthly while you're receiving treatment, and again one month after you stop this medication. Females who are able to get pregnant should use birth control during treatment and for at least 1 month after treatment with Filspari (sparsentan). If you're pregnant or thinking of becoming pregnant, talk to your provider about the risks and benefits of using Filspari (sparsentan) during pregnancy.
Dangerously low blood pressure
- Risk factors: Not enough fluid in your body | Having diarrhea or vomiting for a long time | Low salt levels in your body | Taking other medications that can lower your blood pressure
Filspari (sparsentan) can cause your blood pressure to drop too much, which can make you feel dizzy, tired, or lightheaded. Your risk is higher if you're dehydrated or have medical conditions that cause you to become dehydrated, such as diarrhea or vomiting. If you experience these side effects, your provider might need to change or stop your blood pressure medications (if you're taking any). Or, they might need to temporarily lower the dose of or ask you to stop taking Filspari (sparsentan) until your blood pressure returns to a safe range. Make sure to drink enough water while you're receiving treatment. If you feel dizzy, sit down slowly while holding onto something and let your provider know. If you fall and hit your head, get medical help right away. If you feel dizzy, lightheaded, faint, tired, or confused while taking Filspari (sparsentan), contact your provider right away.
Serious kidney damage
- Risk factors: Heart failure | Kidney problems | Not enough fluid in your body | Taking other medications that can cause kidney damage
Filspari (sparsentan) can affect your kidneys and cause them to not work as well. This can happen to anyone, but the effects can be more severe in people with heart failure, have existing kidney problems, or who take medications that can worsen kidney problems. Your provider might order lab tests every so often to make sure your kidneys are healthy and working properly. If you develop kidney problems (or if your kidney problems worsen) while taking Filspari (sparsentan), your provider might recommend that you stop taking this medication. Let your provider know if you're urinating less often than usual, as this could be a sign that your kidneys aren't working as well.
High potassium levels
- Risk factors: Taking other medications that can raise potassium levels
Filspari (sparsentan) can cause high potassium levels, even in people with healthy kidneys. Your risk is higher if you take other medications that can raise potassium, such as spironolactone (Aldactone) or eplerenone (Inspra). If you experience signs of high potassium levels, such as nausea, muscle weakness, or abnormal heartbeat, tell your healthcare provider right away so they can measure your potassium level. If left untreated, high potassium levels can be dangerous.
Too much fluid
- Risk factors: Heart failure
Filspari (sparsentan) can cause fluid to build-up in the body and lead to swelling. If you have heart failure or any other conditions that can be worsened by fluid build up, let your provider know before starting Filspari (sparsentan). They might recommend for you to take a different medication other than Filspari (sparsentan). Contact your provider right away if you notice unusual swelling in your arms or legs, rapid weight gain, or trouble breathing. They might need to prescribe a water pill for you to get rid of any extra fluid.
Filspari (sparsentan) dosage
Typical dosage for Filspari (sparsentan)
The typical starting dose is 200 mg by mouth once daily. After 2 weeks, your provider will raise the dose to 400 mg once daily. Swallow the whole tablet with water before breakfast or dinner.
Your dose might be different if you have liver problems, are taking a medication that interacts with Filspari (sparsentan), or are having side effects.
Filspari (sparsentan) contraindications
Contraindications are specific health conditions or situations in which a person should not take a medication due to safety concerns. If you have any of the following conditions or if any of the following apply to you, let your healthcare provider know because Filspari (sparsentan) will not be safe for you to take.
- Pregnancy
- Taking angiotensin receptor blockers (ARBs), endothelin antagonists, or aliskiren (Tecturna)
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