Low Molecular Weight Heparin — VTE Treatment / Cancer-Associated Thrombosis Pregnancy: Safe in pregnancy — does not cross placenta; preferred anticoagulant in pregnancy over DOACs

Dalteparin

Brand names: Fragmin

Adult dose

Dose: VTE treatment: 200 units/kg SC once daily (max 18,000 units); Cancer-associated thrombosis: 200 units/kg OD × 30 days then 150 units/kg OD; VTE prophylaxis: 2500–5000 units SC once daily

Route: Subcutaneous injection

Frequency: Once daily (treatment); Once daily (prophylaxis)

Max: 18,000 units/day (VTE treatment)

Preferred LMWH for cancer-associated VTE (CLOT trial). Inject into abdominal wall SC fat, alternating sides. Pre-filled syringes available in fixed doses. Antidote: protamine sulphate (partially reverses — 60–70% anti-Xa activity neutralised).

Paediatric dose

Dose: 100 units/kg units/kg

Route: Subcutaneous

Frequency: Twice daily (treatment); once daily (prophylaxis)

Max: Seek paediatric haematology guidance

BNFc: dosing weight-based; monitor anti-Xa levels in paediatrics

Dose adjustments

Renal

CrCl <30 mL/min: use with caution — consider anti-Xa monitoring or switch to unfractionated heparin

Hepatic

Use with caution in significant hepatic impairment

Paediatric weight-based calculator

Patient weight (kg)

BNFc: dosing weight-based; monitor anti-Xa levels in paediatrics

Clinical pearls

CLOT trial established dalteparin superiority over warfarin for cancer-associated VTE — now standard for 3–6 months before considering DOAC
DOACs (apixaban, rivaroxaban) now also recommended for cancer VTE if low GI/genitourinary bleeding risk — CARAVAGGIO and SELECT-D trials
Anti-Xa monitoring required in obesity (>150 kg), renal impairment, pregnancy — target 0.5–1.0 units/mL (4 hours post-dose, once daily)

Contraindications

Active major bleeding
History of HIT with dalteparin
Severe thrombocytopaenia
Prosthetic heart valves (insufficient data)

Side effects

Bleeding
Thrombocytopaenia (including HIT — less common than UFH)
Injection site reactions
Hyperkalaemia
Osteoporosis (long-term use)
Elevated LFTs

Interactions

Anticoagulants — additive bleeding
NSAIDs/antiplatelets — additive bleeding
ACE inhibitors — hyperkalaemia risk

Monitoring

Anti-Xa levels (selected patients)
FBC (HIT monitoring)
Renal function
Potassium (hyperkalaemia risk)
Signs of bleeding

Reference: BNFc; BNF 90; CLOT Trial 2003; CARAVAGGIO Trial 2020; NICE NG158 (Cancer-Associated VTE). Verify against your local formulary and the latest BNF before prescribing.

Curated clinical cross-links plus same-class fallbacks.

Calculators

Pathways