What Is Hyacyst?

Hyacyst is a sterile solution of sodium hyaluronate that is instilled directly into the bladder to treat interstitial cystitis (IC) and painful bladder syndrome (PBS). It belongs to a class of treatments called intravesical therapies, which deliver medication directly to the bladder lining rather than through the bloodstream.

The active ingredient, sodium hyaluronate (the sodium salt of hyaluronic acid), occurs naturally throughout the body and is an essential component of the bladder’s protective lining. Hyacyst comes as a clear, ready-to-use solution available in two strengths: 40mg and 120mg, both supplied in 50ml volumes.

I want to be upfront about something: Hyacyst is not a cure for IC or PBS. It is a symptom management treatment that works by temporarily replacing a protective layer on the bladder wall. Some patients respond well, while others notice minimal benefit. This variability is common with IC treatments.

How the Treatment Works

To understand Hyacyst, you need some background on bladder physiology.

The Glycosaminoglycan Layer

The inner surface of a healthy bladder is coated with a layer of glycosaminoglycans (GAGs). This protective barrier includes substances like hyaluronic acid, chondroitin sulphate, and heparan sulphate. Working together, they shield the underlying bladder tissue from irritating substances in urine.

Research suggests that many IC/PBS patients have a deficient or damaged GAG layer 1. Without this protection, toxic components of urine can penetrate the bladder wall and trigger the inflammation and pain characteristic of IC—the urgency, frequency, and discomfort that make the condition so debilitating.

Temporary Barrier Replacement

When instilled into the bladder, sodium hyaluronate coats the damaged areas and temporarily substitutes for the missing GAG layer. It does not repair the underlying defect permanently. Instead, it creates a protective buffer that may allow inflamed tissue to heal while reducing symptom severity.

One way to think about it: putting a dressing on a wound does not heal the wound directly, but it protects the area while healing occurs naturally underneath. Hyacyst works on a similar principle, which explains why repeated treatments are typically needed.

Clinical Evidence

The evidence base for sodium hyaluronate bladder instillations is reasonably solid, though most studies are relatively small and long-term data remain limited.

Efficacy Studies

A foundational study published in the Journal of Urology examined 20 patients with refractory IC who received weekly sodium hyaluronate instillations. At follow-up, 60% showed clear improvement with reduced pain and increased bladder capacity 2. These early results helped establish sodium hyaluronate as a viable treatment option.

Longer-term data come from a follow-up study of 121 patients. At five years, 65% of initial responders maintained their improvement with periodic maintenance treatments. Notably, the average treatment interval extended from monthly to approximately once every four months as patients stabilised 3.

Comparative Research

How does sodium hyaluronate compare to other intravesical treatments? One randomised controlled trial compared it with DMSO (dimethyl sulfoxide), an older treatment with more established evidence but significant side effects. After six weeks, 85% of the sodium hyaluronate group reported improvement versus 61% in the DMSO group. The difference did not reach statistical significance in this relatively small study, but sodium hyaluronate was better tolerated.

Combination Therapy

Some clinicians combine sodium hyaluronate with other agents. A study examining hyaluronic acid plus chondroitin sulphate in 126 IC patients found 87% experienced clear symptom improvement at 12 weeks, with 62% maintaining benefit at 12 months.

My honest reading of the evidence: sodium hyaluronate helps a meaningful proportion of IC/PBS patients, with response rates across studies ranging from roughly 50% to 85%. It appears well tolerated with few side effects, which is a genuine advantage. However, the evidence base consists primarily of smaller studies, and not everyone responds.

How Treatment Is Administered

Understanding the practical aspects of Hyacyst treatment helps set realistic expectations.

The Instillation Procedure

Hyacyst is administered by a healthcare professional—typically a urologist or specialist nurse—in an outpatient clinic. The procedure involves inserting a thin catheter through the urethra into the bladder, slowly instilling the sterile Hyacyst solution, removing the catheter, and asking you to retain the solution for as long as comfortable (minimum 30 minutes, ideally longer). You then urinate to empty the bladder.

The procedure itself takes only a few minutes, though you should allow time for the retention period afterward. Most patients tolerate it well. Catheter insertion can be uncomfortable for some, but the instillation of Hyacyst itself rarely causes problems.

Treatment Schedule

The standard protocol begins with weekly instillations for four weeks to build up the protective coating. After this initial phase, treatments are spaced further apart based on individual response. Many patients move to monthly instillations, then gradually extend the interval as symptoms stabilise.

If you receive the higher-strength Hyacyst 120mg, the treatment schedule follows the same pattern as the 40mg version.

Do not be discouraged if improvement is not immediate. Some patients need four to six instillations before experiencing meaningful symptom relief. Response tends to develop gradually over multiple treatments rather than dramatically after a single session.

Treatment Duration

There is no fixed endpoint for Hyacyst therapy. Some patients remain on long-term maintenance, while others are able to stop treatment after a period of stability. If symptoms return after discontinuing, treatment can usually be resumed. The goal is finding the minimum treatment frequency that maintains adequate symptom control for each individual.

Side Effects and Safety Considerations

Hyacyst has a favourable safety profile. Because sodium hyaluronate occurs naturally in the body and the treatment remains local rather than circulating systemically, serious adverse reactions are uncommon.

What to Expect

The most frequently reported issues relate to the catheterisation procedure rather than the Hyacyst solution itself. These may include mild burning or stinging during catheter insertion, brief urgency or discomfort immediately after instillation, and occasional spotting of blood in urine following the procedure.

These effects typically resolve within a day or two. Rarely, some patients experience a temporary flare in IC symptoms shortly after instillation, which usually settles within 24-48 hours.

Contraindications

Hyacyst should not be used in patients with an active urinary tract infection (treatment should be delayed until the infection resolves), known hypersensitivity to hyaluronic acid or any product component, or recent bladder injury or surgery where instillation might cause complications.

There are no known significant drug interactions, and Hyacyst can generally be used alongside other IC medications.

Comparing Hyacyst to Other Treatments

If you are considering Hyacyst, understanding how it compares to alternatives can help inform your decision.

Versus Oral Medications

Oral treatments like pentosan polysulfate sodium (Elmiron) work systemically and require months to show effect. Hyacyst delivers treatment directly to the bladder and may show results more quickly in responsive patients. The trade-off is that Hyacyst requires clinic visits for administration, whereas oral medications can be taken at home.

Versus DMSO

DMSO has a longer track record and is the only FDA-approved intravesical treatment for IC. However, it commonly causes a garlic-like taste and body odour, can temporarily worsen bladder irritation, and requires periodic eye examinations during prolonged use due to potential lens changes. Sodium hyaluronate generally has fewer side effects.

Versus Other Sodium Hyaluronate Products

Several sodium hyaluronate bladder instillation products exist, including Cystistat and iAluRil. They contain the same active ingredient in similar formulations. The choice between them often comes down to availability, prescriber preference, and local commissioning decisions rather than meaningful clinical differences.

Versus Combination Cocktails

Some specialists use “bladder cocktails” combining multiple agents—such as sodium hyaluronate, lidocaine, and heparin—in a single instillation. Limited evidence suggests combination approaches may work better than single agents for some patients, though protocols vary between centres.

Obtaining Hyacyst Treatment

Hyacyst is classified as a medical device rather than a pharmaceutical drug. It requires administration by qualified healthcare professionals, so you cannot purchase it for home use.

In the UK

Hyacyst is available through NHS urology departments for patients meeting clinical criteria. Availability may vary by region depending on local commissioning decisions. Private treatment is an option for those who prefer it or face NHS waiting times.

To access treatment, you typically need a confirmed diagnosis of IC/PBS from a urologist, documentation that first-line treatments have been tried without adequate relief, and assessment confirming intravesical therapy is appropriate for your situation.

Your GP can refer you to a urologist if you are experiencing chronic bladder symptoms that have not responded to initial treatments.

Practical Advice for Patients

Based on clinical experience and patient feedback, here are some practical suggestions for those undergoing Hyacyst treatment.

Empty your bladder just before the procedure. This maximises contact time between the solution and your bladder lining. During the retention period, some patients find it helpful to change positions—sitting, lying on each side, lying on their back—to help the solution coat all areas of the bladder.

After treatment, drink normally but avoid excessive fluid intake in the first few hours. Overdrinking will dilute and flush out the treatment more quickly.

Keep a bladder diary recording symptoms, urgency episodes, and pain levels. This helps you and your clinician objectively assess whether the treatment is working and fine-tune your maintenance schedule. Without tracking, it can be difficult to distinguish gradual improvement from placebo effect.

Questions Worth Asking Your Urologist

Before starting Hyacyst, consider discussing these questions with your specialist:

How many patients have you treated with sodium hyaluronate instillations, and what outcomes have you typically seen?
Based on my specific symptoms, how likely am I to respond to this treatment?
How will we assess whether the treatment is effective, and how many instillations should we try before deciding?
If Hyacyst does not help enough, what would be the next step?
Would combination therapy (such as adding heparin or lidocaine) be worth considering?

Should You Try Hyacyst?

If I had IC/PBS and oral medications were not providing adequate relief, I would consider Hyacyst a reasonable option. The evidence suggests it helps roughly half to three-quarters of patients who try it, the side effect profile is favourable compared to alternatives like DMSO, and the treatment is well established in clinical practice.

That said, go in with realistic expectations. This is symptom management, not a cure. You will probably need repeated treatments, possibly for years. Regular clinic visits for catheterisation are required, which some people find uncomfortable or inconvenient. And there is no guarantee it will work for your particular situation—IC is notoriously variable between patients.

For those who have tried other treatments without success, or who cannot tolerate systemic medications, Hyacyst represents a reasonable option to discuss with your urologist. Give it a proper trial of at least four to six instillations before deciding whether it is helping.

References

Parsons CL. The role of the urinary epithelium in the pathogenesis of interstitial cystitis/prostatitis/urethritis. Urology. 2007;69(4 Suppl):9-16. PubMed
Morales A, Emerson L, Nickel JC, Lundie M. Intravesical hyaluronic acid in the treatment of refractory interstitial cystitis. J Urol. 1996;156(1):45-48. PubMed
Kallestrup EB, Jorgensen SS, Nordling J, Hald T. Treatment of interstitial cystitis with Cystistat: a hyaluronic acid product. Scand J Urol Nephrol. 2005;39(2):143-147. PubMed