What is Difelikefalin: Uses, Dosage, Side Effects and More

Difelikefalin is a prescription medication given through an IV to help people on dialysis who suffer from chronic kidney disease-associated pruritus (CKD-aP). This is the medical term for persistent, often unbearable itching that happens when your kidneys aren't working properly. You might know this medication by its brand name Korsuva, and it works differently from typical itch treatments by targeting specific receptors in your body that control the itch sensation.

What is Difelikefalin?

Difelikefalin is a synthetic medication that mimics certain natural compounds in your body called peptides. It belongs to a class of drugs known as kappa opioid receptor agonists, which means it activates specific receptors in your nervous system without causing the typical effects you'd expect from opioids like morphine or codeine.

The medication was specifically designed to help people whose kidneys aren't filtering waste properly, leading to a buildup of toxins that can cause severe itching. Unlike topical creams or antihistamines that work on your skin's surface, difelikefalin works from the inside out by targeting the nerve pathways that send itch signals to your brain.

What is Difelikefalin Used For?

Difelikefalin treats chronic kidney disease-associated pruritus in adults who are receiving hemodialysis. This condition affects many people with kidney disease and can significantly impact your quality of life, making it difficult to sleep, work, or enjoy daily activities.

The itching from kidney disease isn't like a typical itch you might get from dry skin or a mosquito bite. It's often described as a deep, burning sensation that can occur anywhere on your body but commonly affects your back, arms, and legs. Traditional treatments like antihistamines or topical creams often don't provide adequate relief for this type of itching.

Your doctor might consider difelikefalin if you've tried other treatments without success and your itching is interfering with your daily life. The medication is specifically approved for people already receiving dialysis, as it's given during your dialysis sessions.

How Does Difelikefalin Work?

Difelikefalin works by activating kappa opioid receptors in your peripheral nervous system, which are the nerves outside your brain and spinal cord. When these receptors are activated, they help reduce the transmission of itch signals from your skin to your brain, providing relief from the constant urge to scratch.

What makes this medication unique is that it's designed to stay in your peripheral nervous system rather than crossing into your brain. This targeted approach means you get the anti-itch benefits without experiencing the sedation, euphoria, or addiction potential that comes with traditional opioid medications.

The medication is considered moderately effective for this specific type of itching. While it may not completely eliminate your symptoms, clinical studies show it can significantly reduce itch intensity and improve your overall quality of life when used consistently.

How Should I Take Difelikefalin?

Difelikefalin is given as an intravenous injection directly into your dialysis line during each hemodialysis session. Your healthcare team will administer the medication, so you don't need to worry about giving it to yourself or remembering to take it at home.

The injection is typically given at the end of your dialysis session, after the dialysis treatment is complete but before your access line is removed. The medication is administered slowly over about one minute, and you'll remain in the dialysis center for monitoring after receiving it.

You don't need to make any special dietary changes or preparations before receiving difelikefalin. Since it's given during your regular dialysis appointments, it becomes part of your existing treatment routine without requiring additional visits to the healthcare facility.

How Long Should I Take Difelikefalin For?

The duration of difelikefalin treatment depends on your individual response and how well you tolerate the medication. Many people continue receiving it as long as they're getting dialysis and experiencing benefit from the treatment.

Your doctor will regularly assess how well the medication is working for you and whether you're experiencing any side effects. They'll likely check in with you about your itch levels and overall quality of life to determine if continuing treatment makes sense.

Some people notice improvement in their itching within the first few weeks of treatment, while others may need several months to experience the full benefits. It's important to be patient and consistent with your treatment, as the anti-itch effects tend to build up over time.

What Are the Side Effects of Difelikefalin?

Like all medications, difelikefalin can cause side effects, though not everyone experiences them. The most common side effects are generally mild and manageable, but it's important to know what to watch for.

The most frequently reported side effects include diarrhea, dizziness, nausea, and a temporary fall in blood pressure. These symptoms are usually mild and often improve as your body adjusts to the medication over the first few weeks of treatment.

Here are the common side effects you might experience:

• Diarrhea, which may occur within hours of receiving the injection
• Dizziness or lightheadedness, especially when standing up
• Nausea or mild stomach upset
• Vomiting, though this is less common than nausea
• Temporary drop in blood pressure
• Fatigue or feeling more tired than usual

Most of these side effects are temporary and tend to lessen as your body gets used to the medication. Your dialysis team will monitor you closely, especially during your first few treatments.

While rare, some people may experience more serious side effects that require immediate medical attention. These include severe allergic reactions, significant blood pressure changes, or persistent vomiting that prevents you from keeping fluids down.

Allergic reactions to difelikefalin are uncommon but can include symptoms like difficulty breathing, swelling of your face or throat, or widespread rash. If you experience any of these symptoms, your medical team will stop the medication immediately and provide appropriate treatment.

Who Should Not Take Difelikefalin?

Difelikefalin isn't suitable for everyone, and your doctor will carefully review your medical history before prescribing it. The medication is specifically approved only for adults receiving hemodialysis, so it's not used in people with normal kidney function or those on other types of dialysis.

You should not receive difelikefalin if you have a known allergy to the medication or any of its components. Your doctor will also use caution if you have certain heart conditions, severe liver disease, or a history of significant blood pressure problems.

Here are situations where difelikefalin might not be appropriate:

• Severe heart failure or unstable heart rhythms
• Significant liver disease that affects how your body processes medications
• History of severe allergic reactions to similar medications
• Pregnancy or breastfeeding, as safety hasn't been established
• Severe blood pressure instability
• Active substance abuse involving opioids

Your doctor will weigh the potential benefits against the risks based on your individual health situation. They'll also consider how other medications you're taking might interact with difelikefalin.

Difelikefalin Brand Name

Difelikefalin is marketed under the brand name Korsuva by Cara Therapeutics. This is currently the only brand name available for this medication, as it's a relatively new treatment that received FDA approval in 2021.

When talking with your healthcare team or insurance company, they may refer to the medication by either name. Both Korsuva and difelikefalin refer to the same medication, so don't be confused if you hear both terms used interchangeably.

Difelikefalin Alternatives

If difelikefalin doesn't work well for you or causes troublesome side effects, several alternative treatments exist for kidney disease-related itching. Your doctor can help you explore these options based on your specific situation and medical history.

Traditional treatments include antihistamines like hydroxyzine or cetirizine, though these are often less effective for kidney-related itching. Topical treatments such as menthol-based creams or calamine lotion may provide some relief, especially when used alongside other therapies.

Other prescription alternatives include gabapentin, which affects nerve signals differently than difelikefalin, or pregabalin, another medication that can help with nerve-related symptoms. Some people find relief with ultraviolet light therapy, though this requires special equipment and monitoring.

In some cases, optimizing your dialysis treatment itself can help reduce itching. This might involve adjusting your dialysis schedule, changing the type of dialyzer used, or modifying your fluid removal rates.

Is Difelikefalin Better Than Other Medications?

Difelikefalin offers some unique advantages over traditional treatments for kidney disease-related itching, but whether it's "better" depends on your individual response and circumstances. Unlike antihistamines, which often don't work well for kidney-related itching, difelikefalin specifically targets the nerve pathways involved in this type of itch.

Compared to medications like gabapentin, difelikefalin is given during dialysis rather than requiring daily pills at home. This can be more convenient and ensures you don't miss doses, but it also means you can only receive it if you're getting regular hemodialysis.

The medication tends to cause fewer central nervous system side effects than some alternatives because it doesn't cross into your brain. This means less drowsiness or cognitive effects compared to medications like antihistamines or certain anti-seizure drugs used for itching.

However, difelikefalin may cause more gastrointestinal side effects like diarrhea compared to topical treatments. Your doctor will help you weigh these factors when deciding on the best treatment approach for your situation.