Subcutaneous Furosemide: Taking Diuresis Outside the Hospital

The standard treatment for diuresis in patients with worsening heart failure (HF), is furosemide, which is typically given in an intravenous (IV) form in a hospital setting, but that may not be necessary for the future.

scPharmaceuticals’s has developed a pH neutral formulation of furosemide to be delivered subcutaneously via a wearable, Infusor (sc2Wear Infusor), which could alleviate the burden on both patient and clinician. The subcutaneous formula was developed to match pH of the human body (pH 7.4), which has been shown to achieve therapeutic levels of furosemide within 30 minutes of administration after subcutaneous administration and maintained for up to 5 hours.

A study presented at this year’s Heart Failure Society of America's 21st Annual Scientific Meeting in Dallas, Texas, demonstrated that the sc2Wear Furosemide Infusor was able to deliver a therapeutic dose, was generally safe and well tolerated with minimal interference on activities of daily living. The sc2Wear Furosemide Infusor is a potential alternative to IV administration of furosemide and the company plans to file a new drug application by the end of the year.

The drug is delivered in a dual phase process via a small needle (27G) into the skin of the abdominal wall. During the process, 10 mL of the formulation (8 mg/mL) is administered over 5 hours. In the first hour, 30 mg is delivered, followed by 12.5 mg per hour the remaining 4 hours.

This biphasic 80 mg dose is delivered over 5 hours and was compared to 2x 40 mg doses of IV furosemide given at hours 0 and 2. In current clinical trials, subcutaneous furosemide was shown to have 100% bioavailability (t:0-24 hours), and diuresis at 8 hours was 2654 mL compared to 2610 mL by IV. When compared at the 24-hour mark, diuresis measured 3630 mL for subcutaneous and 3538 mL for IV.

“I think that ultimately, it could be something that's really useful for patients, and really useful for providers of all types - physicians, nurses, etc.,” James Udelson (pictured, above), MD, the chief of cardiology at Tufts Medical Center, told MD Magazine. “It provides a way to give what is essentially, and that provides the same furosemide levels and action as, an intravenous dose without having to start an IV and to monitor the patient in the clinic.”

The idea of patients achieving diuresis within their own home is appealing to both those being treated as well as the clinician providing treatment. Udelson noted the process can be a long one, sometimes taking upwards of 5 to 6 hours, before the patient can go home, all the while requiring consistent monitoring by the attending physician. The introduction of a formulation of furosemide that can be administered subcutaneously would alleviate that need, allowing patients to administer their own treatment, and only requiring a check-in after the process was completed.

“With the [drug-device combination] that's being developed, once you educate the patient how to use it, you plug it on, and it’s a subcutaneous injection, and there's now been a couple of studies showing that you get equivalent levels to an intravenous dose and equivalent urine output,” Udelson said. “You could prescribe that for 1 day or several days in a row, keep in touch with the patient, and it provides a way to essentially use the same the same action as intravenous, but not having an intravenous line and being in a clinic or in a hospital.”

Patients with heart failure are often admitted to the hospital for issues related to diuresis, and many times, it is due to the development of resistance to, or unresponsiveness to, oral diuretics, which can and should be done at home, Bertram Pitt (pictured, below), MD, professor of medicine emeritus at the University of Michigan School of Medicine, told MD Magazine.

“From the initial studies that have been done, [subcutaneous furosemide] gives about the same [level of diuresis] as IV up to about 120 mg,” Pitt said. “When you give it through IV there are peaks, and those peaks are over the threshold. And if you're over the threshold, it's wasted. So the actual amount of furosemide that you're giving that works is pretty equivalent whether IV or subcutaneous.”

Keeping patients out of the hospital, although trending in the right direction, is not the only potential positive that the sc2Wear Furosemide Infusor could provide. Were it to be approved for use, it could also aid the struggles faced by patients of having to travel to diuresis clinics and nursing homes, which can be considered problematic.

According to Lisa Rathman, MSN, a heart failure nurse practitioner at Lancaster General Hospital, there are many nursing homes and personal care homes that simply do not have the staff to accommodate the needs of patients with HF in need of IV diuresis.

“For them, it would be so much easier to be able to do a subcutaneous injection rather than doing IV, and I think that's absolutely clear,” Rathman said. “The other place I think would be very helpful is personal care homes because they definitely do not have nursing staff to do that. They may just have medical assistants, who don't have the ability to give any kind of IV diuretics.”