Which drugs increase neutrophils? An overview of key medications and mechanisms

October 14, 2025 •

3 min read

A single dose of a corticosteroid like prednisone can increase neutrophil counts by 30-50% within hours, a phenomenon known as steroid-induced neutrophilia. Understanding which drugs increase neutrophils is critical for both therapeutic purposes, like treating neutropenia, and for correctly interpreting blood tests where it appears as a side effect.

Quick Summary

This article explains how certain medications, including granulocyte colony-stimulating factors (G-CSF), corticosteroids, and lithium, cause a rise in neutrophil levels by stimulating bone marrow production, inhibiting cellular migration, or prolonging their lifespan. It differentiates between intentional and unintended neutrophilia.

Key Points

G-CSFs (Filgrastim, Pegfilgrastim): These are therapeutic growth factors that directly stimulate the bone marrow to produce more infection-fighting neutrophils.
Corticosteroids (Prednisone, Dexamethasone): They cause a temporary increase in neutrophil count (neutrophilia) as a side effect by redistributing cells from vessel walls, slowing their exit from circulation, and extending their lifespan.
Lithium : This mood stabilizer can cause an increase in total white blood cell count, particularly neutrophils, by promoting the production of hematopoietic growth factors.
Drug-Induced vs. Therapeutic Neutrophilia: It is critical to distinguish between intentional increases (like with G-CSF) and unintended side effects, especially with corticosteroids, to prevent misdiagnosis of an infection.
Management Depends on Cause: Management of high neutrophil counts varies, from simply monitoring for corticosteroid-induced neutrophilia to stopping or adjusting the causative medication if it is an adverse effect.
Other Drugs: Some other medications, including certain antibiotics, antipsychotics (e.g., clozapine), and stimulants like catecholamines, can also cause neutrophilia.

Neutrophils are the most common type of white blood cell and serve as a crucial component of the innate immune system, acting as a first line of defense against bacterial infections. A low neutrophil count, known as neutropenia, can leave a person vulnerable to severe infections. Conversely, a high count (neutrophilia) can also be a sign of disease but is sometimes a side effect of medication. A variety of drugs can either intentionally boost neutrophil production or cause a temporary increase as a byproduct of their primary action.

Granulocyte Colony-Stimulating Factors (G-CSFs)

Granulocyte Colony-Stimulating Factors (G-CSFs) are a class of protein-based medications specifically designed to increase neutrophil counts. They function like a natural growth factor that signals the bone marrow to produce more white blood cells.

How G-CSFs work

G-CSFs stimulate the bone marrow to increase production and release of neutrophils into the bloodstream. They also activate the functional capabilities of circulating neutrophils.

Therapeutic uses of G-CSFs

G-CSF drugs are vital for managing neutropenia, particularly in cancer treatment. Common G-CSF medications include filgrastim (Neupogen®, Nivestym®, Zarxio®), pegfilgrastim (Neulasta®, Fulphila®, Ziextenzo®), and tbo-filgrastim (Granix®). These are used after chemotherapy to reduce neutropenia and infection risk, for stem cell transplants, and in chronic neutropenia.

Corticosteroids (Glucocorticoids)

Corticosteroids are used for their anti-inflammatory and immunosuppressive effects. They can cause steroid-induced neutrophilia as a side effect.

How corticosteroids increase neutrophils

Corticosteroids primarily increase neutrophils by causing them to detach from blood vessel walls and enter circulation (demargination), inhibiting their movement into tissues, and delaying their natural death. This effect is temporary. Examples include prednisone, dexamethasone, and methylprednisolone.

Lithium

Lithium carbonate is a mood stabilizer used for bipolar disorder. It can cause an increase in white blood cells, including neutrophils, as a side effect.

How lithium increases neutrophils

The exact mechanism is not fully understood, but it is thought to involve stimulating the bone marrow. Lithium has been used experimentally to manage neutropenia in some cases.

Comparison of Medications That Increase Neutrophils


Feature	G-CSFs (Filgrastim, Pegfilgrastim)	Corticosteroids (Prednisone, Dexamethasone)	Lithium (Lithium carbonate)
Mechanism	Stimulates bone marrow production and release of new neutrophils.	Redistributes neutrophils from vessel walls, inhibits migration, and delays apoptosis.	Stimulates bone marrow production, likely via increased hematopoietic growth factors.
Intended Effect?	Yes, specifically designed to raise neutrophil counts.	No, an unintended side effect of primary anti-inflammatory action.	No, an unintended side effect of primary mood-stabilizing action.
Onset	Typically takes several days for bone marrow to respond.	Rapid, often within hours of administration.	Occurs over days to weeks with ongoing treatment.
Duration	Lasts as long as therapy continues, though long-acting forms extend effect.	Temporary, reversible upon discontinuation of the drug.	Reversible, returns to baseline upon discontinuation.

Managing Medication-Induced Neutrophilia

For G-CSF, neutrophilia is the desired outcome and is managed by monitoring blood counts. For other drugs, management depends on the situation:

Corticosteroid Neutrophilia: This is generally harmless and doesn't require specific treatment, but recognizing it is important to avoid misinterpreting it as an infection.
Lithium Neutrophilia: Typically mild and may not need treatment unless other issues arise from lithium. Counts return to normal if the drug is stopped.

Identifying the cause is key to managing elevated neutrophil counts. This might involve stopping or adjusting the medication if the elevation is an unwanted effect.

Conclusion

Several drugs can increase neutrophil counts through different actions. G-CSFs like filgrastim and pegfilgrastim intentionally stimulate bone marrow to produce more neutrophils. Corticosteroids, such as prednisone, cause a temporary rise by redistributing neutrophils and slowing their removal from circulation. Lithium can also increase neutrophil counts by enhancing bone marrow activity. Managing drug-induced neutrophilia depends on whether it is a therapeutic goal or an unintended side effect. For unintended increases, careful evaluation is crucial to avoid misdiagnosis. Healthcare providers need to understand these drug effects for accurate diagnosis and patient care. For more details on specific medications, consult resources like FDA drug labels or medical databases {Link: droracle.ai https://www.droracle.ai/articles/36489/do-steroids-cause-increase-in-neutrophils}.

Frequently Asked Questions

The purpose is to treat or prevent neutropenia, a condition characterized by low neutrophil levels. This is especially common in patients undergoing chemotherapy, where a low neutrophil count increases the risk of serious bacterial infections.

G-CSF medications like filgrastim (Neupogen) are recombinant, or man-made, versions of the naturally occurring human granulocyte colony-stimulating factor protein. They function in the same way to stimulate neutrophil production in the bone marrow.

A medical professional will differentiate based on your clinical picture and other lab results. Steroid-induced neutrophilia is not a sign of infection and usually does not come with other symptoms like fever, whereas infection-related neutrophilia is accompanied by signs of illness.

In most cases, a high neutrophil count from medication is benign. However, for medications like G-CSF, there is a risk of serious complications like spleen rupture, though this is rare. Overall risks depend on the specific medication and the underlying health of the patient.

No, lithium's effect actually increases the total neutrophil count. While the mechanism isn't fully clear, this is a known side effect in psychiatric patients and has been explored as a benefit to help mitigate neutropenia in other settings.

Whether it is safe to continue depends on the drug and the reason for the high neutrophil count. For therapeutic drugs like G-CSF, the effect is desired. For a side effect, a doctor will weigh the benefits and risks of continuing the medication.

If a medication causing neutrophilia is essential, a doctor will closely monitor blood counts. For conditions like corticosteroid-induced neutrophilia, no specific treatment may be needed. In other cases, adjusting the dose or frequency might be considered to manage the neutrophil levels.