Which medications can increase the white blood cell count in an 86-year-old woman with neutrophilic leukocytosis?

Medications That Increase White Blood Cell Count

Corticosteroids are the most common and clinically significant medications that increase WBC count, with high-dose steroids causing increases up to 4.84 × 10⁹/L within 48 hours, predominantly through neutrophil demargination. 1

Primary Medications Causing Leukocytosis

Corticosteroids (Most Common)

• Systemic corticosteroids (prednisone, methylprednisolone, dexamethasone) cause dose-dependent leukocytosis that can be extreme and persistent even with small doses 2
• Peak WBC elevation occurs at 48 hours after administration 1
• Expected increases by dose:
  • Low dose: 0.3 × 10⁹/L
  • Medium dose: 1.7 × 10⁹/L
  • High dose: 4.84 × 10⁹/L 1
• Mechanism: Decreased neutrophil adhesion molecule expression (Mac-1 and L-selectin), causing demargination from vessel walls rather than increased production 3
• Pattern: Predominantly neutrophilic with concurrent monocytosis, eosinopenia, and lymphopenia 2

Critical caveat: Steroid-induced leukocytosis typically lacks left shift (band forms <6%) and toxic granulation—if these are present, suspect infection instead 2

Inhaled Corticosteroids

• Budesonide and fluticasone can increase WBC by 12-30% within 6 hours of single-dose inhalation 3
• Mechanism identical to systemic steroids (reduced neutrophil adhesion molecules)
• Clinically relevant in emergency settings where acute WBC changes may influence decision-making 3

Granulocyte Colony-Stimulating Factors (G-CSF)

These are therapeutic agents used intentionally to increase WBC in specific clinical contexts:

• Filgrastim, pegfilgrastim, tbo-filgrastim, filgrastim-sndz 4
• GM-CSF (granulocyte-macrophage colony-stimulating factor) 4
• Used primarily in oncology for chemotherapy-induced neutropenia
• Should be discontinued if ANC exceeds 20 × 10⁹/L 4

Carbamazepine

• Can cause significant leukocytosis (WBC >21 × 10⁹/L documented) 5
• Effect resolves within days of discontinuation and recurs with rechallenge 5
• Less commonly recognized but well-documented cause

Vitamin C (Emerging Evidence)

• High-dose oral vitamin C (5000-7000 mg daily) increased WBC and neutrophil counts in case report 6
• Evidence limited to single case study; clinical applicability uncertain

Clinical Approach for Your 86-Year-Old Patient

For an elderly woman with neutrophilic leukocytosis, systematically review:

1. Medication history: Focus on corticosteroids (any route), carbamazepine, G-CSF agents
2. Timing: Steroid-induced peaks at 48 hours; if WBC rising beyond this or with low-dose steroids, consider alternative causes 1
3. Differential pattern: Check for left shift and toxic granulation—their presence suggests infection over drug effect 2
4. Dose-response: Increases >4.84 × 10⁹/L suggest causes beyond high-dose steroids 1

In this age group, always exclude infection, malignancy (chronic neutrophilic leukemia, other MPNs), and inflammatory conditions before attributing leukocytosis solely to medications 7, 8.