Releuko

How Hard Is It to Find Releuko in Stock?

Releuko is not listed on the FDA's Drug Shortage Database as an active national shortage as of 2026. However, it receives a findability score of 55 out of 100 on medfinder, reflecting that it is challenging to locate at retail pharmacies due to its specialty distribution model. Releuko is primarily distributed through specialty pharmacy channels and oncology clinic buy-and-bill programs — not through standard retail pharmacy wholesale networks.

Patients filling Releuko at retail pharmacies often encounter difficulty finding it in stock, especially at chain pharmacies like CVS and Walgreens. Specialty pharmacies such as Accredo, CVS Specialty, and Walgreens Specialty are more reliable sources. Cold-chain requirements (refrigeration at 2–8°C), prior authorization requirements from most insurers, and the inability to automatically substitute other filgrastim products all contribute to access challenges.

If you're having trouble locating Releuko, medfinder calls pharmacies near you to check which ones have it in stock and can fill your prescription. Results are texted to your phone, saving you hours of calling on hold.

Who Can Prescribe Releuko?

Releuko is not a controlled substance and therefore has no DEA-specific prescribing restrictions. Any licensed prescriber — physician (MD/DO), nurse practitioner (NP), or physician assistant (PA) — can prescribe it in states where their scope of practice allows. In practice, Releuko is almost exclusively prescribed by specialists who manage the conditions requiring G-CSF therapy.

Medical Oncologists — Primary prescribers for cancer patients receiving myelosuppressive chemotherapy

Hematologists — For blood disorders including AML, severe chronic neutropenia, and bone marrow failure

Pediatric Oncologists/Hematologists — For children with congenital, cyclic, or idiopathic neutropenia

Bone Marrow Transplant Specialists — For myeloablative chemotherapy and BMT support

Primary Care Physicians — May manage ongoing therapy for patients with established chronic neutropenia diagnoses

Telehealth options are expanding but limited for new Releuko initiations, which typically require in-person evaluation, CBC lab results, and imaging. Established patients with chronic neutropenia on stable home-administered Releuko therapy may be able to manage follow-up and dose adjustments through telehealth appointments with their hematologist.

Is Releuko a Controlled Substance?

No. Releuko (filgrastim-ayow) is not a controlled substance. It is not scheduled by the Drug Enforcement Administration (DEA) and has no abuse potential. Releuko is a biologic medication — a recombinant protein — and is not a narcotic, stimulant, or sedative.

Because it is not a controlled substance, there are no DEA-mandated prescription restrictions such as limits on quantity dispensed, required in-person prescriber visits, or prohibition of electronic prescribing. Releuko can be prescribed electronically, called in to a pharmacy, or faxed — standard for any non-controlled prescription medication. However, it does require a valid prescription and is available only through specialty pharmacy channels due to its biologic nature and storage requirements.

Common Side Effects of Releuko

The most commonly reported side effects of Releuko (filgrastim-ayow) include:

Bone pain (most common — caused by increased bone marrow activity)

Fever (pyrexia)

Rash and skin reactions

Cough and shortness of breath

Nosebleeds (epistaxis)

Diarrhea and nausea

Injection site reactions (redness, bruising, swelling)

Hair loss (alopecia) — primarily in long-term chronic neutropenia use

Serious Side Effects — Seek Immediate Care

Splenic rupture (rare, potentially fatal — left upper abdominal or shoulder pain is a warning sign)

Acute respiratory distress syndrome (ARDS)

Anaphylaxis (serious allergic reaction — contraindicated if prior serious allergy to filgrastim or pegfilgrastim)

Glomerulonephritis (kidney inflammation — hematuria, proteinuria)

Sickle cell crisis (in patients with sickle cell disease — avoid use or use with extreme caution)

MDS/AML risk (long-term use in congenital neutropenia patients — requires ongoing CBC monitoring)

Final Thoughts on Releuko

Releuko (filgrastim-ayow) is a valuable filgrastim biosimilar that plays a critical role in oncology care. As the third filgrastim biosimilar approved by the FDA, it provides another option for patients and providers seeking alternatives to the more expensive brand Neupogen. For most standard indications — particularly chemotherapy-induced neutropenia — Releuko is clinically equivalent to Neupogen and other filgrastim biosimilars, with comparable safety and efficacy data.

The primary challenges with Releuko are practical rather than clinical: specialty-only distribution, cold-chain requirements, insurance step therapy protocols, and the inability to auto-substitute at the pharmacy. Patients and providers who understand these barriers and plan ahead — submitting PAs early, establishing specialty pharmacy relationships, and knowing when to switch to an available alternative — will have the best experience with Releuko.

If you're struggling to find Releuko in stock, medfinder can help. medfinder calls pharmacies near you to find which ones have Releuko available and can fill your prescription. Results are texted to you, so you can focus on your treatment — not the pharmacy search.