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Erythropoiesis-Stimulating Agent (Long-Acting ESA)

Darbepoetin Alfa

Brand names: Aranesp

Adult dose

Dose: 0.45 mcg/kg SC or IV once weekly. Alternative: 0.75 mcg/kg once every 2 weeks.
Route: Subcutaneous (preferred in non-dialysis CKD) or IV (dialysis patients)
Frequency: Once weekly or once fortnightly
Max: Target Hb 100–120 g/L; reduce dose if Hb >120 g/L or rises >20g/L over 4 weeks
Longer half-life than epoetin alfa (~25h SC vs ~8h) — weekly or fortnightly dosing. Dose conversions from epoetin: epoetin 200 units/week ≈ darbepoetin 1 mcg/week. Ensure iron replete before starting (TSAT >20%, ferritin >200 ng/mL in dialysis; >100 ng/mL in non-dialysis CKD).

Paediatric dose

Dose: 0.45 mcg/kg
Route: SC or IV
Frequency: Once weekly
Max: Target Hb as per adult CKD protocol
Concentration: 10 mcg/mL, 25 mcg/mL, 40 mcg/mL prefilled syringes mcg/ml
Paediatric CKD anaemia (>1 year): 0.45 mcg/kg once weekly SC. Target Hb 100–120 g/L. Specialist paediatric nephrology.

Dose adjustments

Renal

No dose adjustment required — designed for CKD patients; dose titrated to Hb response

Hepatic

No dose adjustment required

Paediatric weight-based calculator

Paediatric CKD anaemia (>1 year): 0.45 mcg/kg once weekly SC. Target Hb 100–120 g/L. Specialist paediatric nephrology.

Clinical pearls

  • Dosing frequency advantage: once weekly or fortnightly vs epoetin three times weekly — significantly improves patient convenience and injection burden
  • TREAT trial: Hb target >130 g/L with ESAs is harmful — increased stroke and cardiovascular death; target 100–120 g/L only
  • Iron deficiency must be corrected first — ESAs are completely ineffective if iron-deficient; IV iron is preferred in CKD (ferric carboxymaltose or iron sucrose)
  • ESA hyporesponsiveness (Hb not rising despite escalating dose): investigate — most common cause is iron deficiency, inflammation (high CRP), bleeding, or underdialysis
  • Pure red cell aplasia (PRCA): rare but serious — anti-darbepoetin antibodies; suspected if sudden Hb drop with low reticulocyte count; stop ESA and discuss with haematology/transplant

Contraindications

  • Uncontrolled hypertension
  • Pure red cell aplasia (ESA-associated)
  • Hypersensitivity to darbepoetin or excipients

Side effects

  • Hypertension (can worsen existing hypertension — monitor BP at each visit)
  • Thrombosis (AVF thrombosis in haemodialysis patients)
  • Flu-like symptoms (injection site reactions)
  • Pure red cell aplasia (rare — anti-erythropoietin antibodies)
  • Headache
  • Rash

Interactions

  • ACEi/ARBs — may blunt ESA response (reduce haematopoietic effect)
  • Ciclosporin — may require dose adjustment

Monitoring

  • Haemoglobin (every 2–4 weeks during dose titration; monthly when stable)
  • Iron stores (TSAT and ferritin — monthly in dialysis, every 3 months in non-dialysis CKD)
  • Blood pressure (at each visit)
  • Reticulocyte count (if ESA hyporesponsiveness or PRCA suspected)

Reference: BNFc; BNF; KDIGO Anaemia in CKD Guidelines 2012; TREAT Trial (NEJM 2009); NICE NG203. Verify against your local formulary and the latest BNF before prescribing.

Related

Curated clinical cross-links plus same-class fallbacks.

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