Pegylated G-CSF Pregnancy: Available data with pegfilgrastim in pregnant women are insufficient to establish a drug-associated risk; published filgrastim studies have not established an association with major birth defects, miscarriage, or adverse maternal/fetal outcomes.

Pegfilgrastim

Brand names: Neulasta, Pelmeg, Ziextenzo, Pelgraz

Pegfilgrastim is a long-acting pegylated granulocyte colony-stimulating factor (G-CSF) used to reduce the duration of neutropenia and incidence of febrile neutropenia after myelosuppressive chemotherapy.

Auto-extracted from the source labelling — not yet independently clinician-verified. These values were distilled from the UK SPC (or the US label where noted) but have not had a clinician sign-off. Confirm against the current SmPC before prescribing.

Adult dose

Dose: 6 mg as a single subcutaneous injection once per chemotherapy cycle

Route: Subcutaneous

Frequency: Once per chemotherapy cycle; do not administer between 14 days before and 24 hours after cytotoxic chemotherapy

Product: UDENYCA (US labelling; no UK SPC captured). For patients with cancer receiving myelosuppressive chemotherapy. Hematopoietic subsyndrome of acute radiation syndrome: two doses of 6 mg each subcutaneously one week apart (give first dose as soon as possible after suspected/confirmed exposure to >2 Gy). Paediatric patients weighing less than 45 kg require weight-based dosing (US label Table 1): less than 10 kg = 0.1 mg/kg (0.01 mL/kg); 10–20 kg = 1.5 mg; 21–30 kg = 2.5 mg; 31–44 kg = 4 mg. The prefilled autoinjector is not suitable for patients weighing less than 45 kg.

Dose auto-extracted from US FDA prescribing information (openFDA / DailyMed) — cross-check; US labelling may differ from UK — not yet clinician-verified. Always confirm against the product SmPC and your local formulary before prescribing.

Contraindications

History of serious allergic reactions (including anaphylaxis) to pegfilgrastim products or filgrastim products

Side effects

Bone pain
Pain in extremity
Splenic rupture (including fatal cases)
Acute respiratory distress syndrome
Serious allergic reactions, including anaphylaxis

Clinical monograph

How it works

It stimulates proliferation, differentiation and release of neutrophils from the bone marrow by acting on the G-CSF receptor; pegylation prolongs its half-life through reduced renal clearance.

Prescribing in practice

It must not be given in the period immediately before or after cytotoxic chemotherapy as this may worsen myelosuppression; observe the recommended interval around chemotherapy dosing.
Splenic rupture and capillary leak syndrome are rare but serious; left upper abdominal or shoulder-tip pain should prompt assessment.
A single dose is given per chemotherapy cycle by subcutaneous injection in line with the SPC.

Monitoring

Monitor full blood count and watch for splenomegaly, signs of capillary leak syndrome and pulmonary or allergic reactions.

Counselling the patient

Explain that bone pain is a common side effect and can usually be managed with simple analgesia.
Advise reporting left upper abdominal or shoulder pain, breathlessness or signs of infection promptly.

Evidence & guidelines

Randomised trials support pegfilgrastim given once per cycle as comparable to daily filgrastim for chemotherapy-induced neutropenia.

Reference: ESMO febrile neutropenia guidelines; NICE/SACT protocols; SmPC; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. The structured dose values shown have been reviewed by a clinician. Monograph status: clinician-reviewed (2026-07-04).

Curated clinical cross-links plus same-class fallbacks.

Pathways