PEG-NEUTAS (PEGFILGRASTIM INJECTION 6MG/0.6ML)

Indications

• Reduction in duration of neutropenia
• Reduction in incidence of febrile neutropenia in patients undergoing cytotoxic chemotherapy for malignancy

Dosage

Children: Refer to the BNF for Children for paediatric dosing guidelines.

Adults: 6 mg for each chemotherapy cycle, administered subcutaneously approximately 24 hours after chemotherapy.

Mechanism of action

Pegfilgrastim acts by binding to the granulocyte-colony stimulating factor receptor (G-CSFR) on hematopoietic progenitor cells, stimulating their proliferation and differentiation into neutrophils. This enhances the body's ability to produce neutrophils, which are critical for fighting infections, particularly during periods of myelosuppression due to chemotherapy.

Pharmacodynamics

Pegfilgrastim increases the number of neutrophils in circulation, leading to a faster recovery from neutropenia following chemotherapy. It also enhances the function of neutrophils, improving their ability to respond to infections. The prolonged half-life of pegfilgrastim, due to its pegylation, allows for less frequent dosing compared to unmodified G-CSF.

Pharmacokinetics

Pegfilgrastim is administered via subcutaneous injection, with a peak plasma concentration typically occurring within 24 to 48 hours post-injection. The drug has a half-life of approximately 15 to 80 hours, depending on individual patient factors. It is primarily eliminated through the reticuloendothelial system, with no significant renal clearance. Dosage adjustments may be necessary in patients with impaired renal function.

Contra-indications

• Hypersensitivity to pegfilgrastim or any of its components
• Acute leukaemia
• Myelosuppressive chemotherapy in patients with chronic myeloid leukaemia or myelodysplastic syndromes

Adverse effects

• Common: Chest pain, hypokalaemia, skin eruption, myalgia, nausea, malaise, musculoskeletal pain, flatulence, gastrointestinal discomfort, headache
• Uncommon: Glomerulonephritis
• Frequency not known: Postural hypotension, splenomegaly, syncope, oral hypoaesthesia, sleep disorders, vomiting

Interactions

• No specific drug interactions are noted, but caution is advised when used with other myelosuppressive agents

Precautions

• Monitor platelet and white blood cell counts regularly
• Use effective contraception during treatment due to teratogenic effects in animal studies
• Patients should be cautioned about potential dizziness and fatigue affecting driving and skilled tasks
• Dose adjustment may be required for patients with creatinine clearance of 20-50 mL/min

Pregnancy

Manufacturer advises avoiding use due to potential teratogenic effects observed in animal studies.

Breast-feeding

Manufacturer advises avoiding use as there is no available information on excretion in breast milk.

Storage

Store in a refrigerator (2°C to 8°C). Do not freeze. Protect from light.

Formulations

• Pegfilgrastim 6 mg/0.6 ml solution for injection in pre-filled syringes (Neulasta, Pelgraz)