Dalteparin

Class: Low-Molecular-Weight Heparin (LMWH)

Route: Subcutaneous (SC)

Anticoagulant effect: Predominantly anti-factor Xa (anti-Xa > anti-IIa)

Mechanism of Action

Dalteparin binds to antithrombin (AT), enhancing AT-mediated inhibition of:

Compared with unfractionated heparin (UFH), dalteparin has:

  • More predictable pharmacokinetics
  • Less nonspecific protein binding
  • Reduced endothelial binding
  • Lower risk of HIT

Approved & Common Clinical Indications

  • VTE treatment (DVT ± PE)
  • VTE prophylaxis (medical and surgical patients)
  • Cancer-associated thrombosis (CAT) – historically preferred LMWH
  • Unstable angina / NSTEMI (less common now with DOACs)
  • Bridging anticoagulation (peri-procedural, selected cases)
  • Pregnancy-associated VTE (off-label but widely used)

Monitoring

Routine Monitoring

❌ Not required in most patients

Anti-Xa Monitoring (when indicated)

Consider in:

  • Severe renal impairment
  • Extremes of body weight
  • Pregnancy
  • Pediatrics
  • High bleeding risk
  • Prolonged therapy

Target anti-Xa levels (4 hours post-dose):

  • Once-daily dosing: 1.0–2.0 IU/mL
  • Twice-daily dosing: 0.5–1.0 IU/mL

Adverse Effects

Common

  • Bleeding
  • Injection-site hematoma
  • Anemia

Serious

  • Heparin-induced thrombocytopenia (HIT) (lower risk vs UFH)
  • Spinal/epidural hematoma (neuraxial anesthesia)
  • Osteoporosis (long-term use)

Contraindications / Precautions

  • Active major bleeding
  • History of HIT (cross-reactivity possible)
  • Severe thrombocytopenia
  • Recent CNS, spinal, or ophthalmic surgery
  • Concomitant neuraxial procedures

Reversal

  • Protamine sulfate
    • Partially reverses anti-Xa activity (~60%)
    • More effective for anti-IIa activity
      📌 No complete antidote unlike UFH

Drug Interactions

↑ Bleeding risk with:

  • Antiplatelets (ASA, clopidogrel)
  • NSAIDs
  • Other anticoagulants
  • SSRIs/SNRIs (additive bleeding risk)

Special Populations

Pregnancy

  • Does not cross placenta
  • Preferred over warfarin
  • Anti-Xa monitoring often used

Obesity

  • Weight-based dosing recommended
  • Monitor anti-Xa in morbid obesity

Pediatrics

  • Weight-based dosing
  • Anti-Xa monitoring recommended

Clinical Pearls for Pharmacists

  • SC injection only — never IM
  • Rotate injection sites; avoid expelling air bubble
  • Platelet count baseline + periodic (HIT surveillance)
  • Hold before invasive procedures (typically 24 hrs therapeutic dose)
  • Consider DOAC transition when appropriate (non-pregnant, non-cancer)

Comparison Snapshot

Feature Dalteparin UFH DOACs
Monitoring Minimal aPTT None
Renal impact Moderate Minimal High
HIT risk Low High None
Reversal Partial Complete Drug-specific
Pregnancy Preferred Acceptable Avoid

Dosing Summary

VTE Prophylaxis
CrCl CrCl > 30 ml/min CrCl < 30 ml/min
Body Weight (KG) < 40  40-100 101-120 121-170 171-230 > 230  
Dose (SC units) 2,500 once daily 5,000 once daily 7,500 once daily 5,000 BID 7,500 BID 10,000 BID Heparin 5,000 BID
Therapeutic Anticoagulation
Body Weight (KG) 46-56 57-68 69-82 83-94 95-105 106-117 118-130 131-140 141-155
Dose (SC units) 10,000 q24h 12,500 q24h 15,000 q24h 18,000 q24h 10,000 q12h 10,000 qam and 12,500  nightly 12,500 q12h 12,500 qam and 15,000 nightly 15,000 q12h
Indication Adult Dose (Normal Renal Function, CrCl ≥30 mL/min) Renal Impairment (CrCl <30 mL/min) Weight-Based Adjustment Pediatric Dose Elderly Considerations
DVT/PE Treatment (VTE) 200 IU/kg SC once daily (max 18,000 IU) for 1 month → then 150 IU/kg SC once daily Use with caution; monitor anti-Xa. Consider UFH if severe CKD. Dose capped at 18,000 IU/day 100 IU/kg SC q12h (max 10,000 IU per dose) Higher bleeding risk; monitor CBC, anti-Xa if renal function borderline
Extended VTE Treatment in Cancer 200 IU/kg SC once daily for 1 month (max 18,000 IU) → 150 IU/kg SC once daily for months 2–6 Same as above; avoid if CrCl <30 unless anti-Xa guided Same max cap applies Limited data; use 150 IU/kg q24h (monitor anti-Xa) More cautious dosing; renal monitoring essential
Post-Orthopedic Surgery Prophylaxis 2,500 IU SC 1–2 h pre-op, then 2,500–5,000 IU SC once daily Avoid in severe renal impairment (UFH preferred) Fixed dose Not recommended (limited data) Increased bleeding risk; weigh benefit vs risk
Unstable Angina / Non–Q-wave MI 120 IU/kg SC q12h (max 10,000 IU/dose) with aspirin Use with caution; anti-Xa monitoring if CrCl <30 Max dose cap applies Not routinely used in pediatrics Monitor renal function and anti-Xa more closely

Key Pharmacist Notes

  • Renal clearance: Dalteparin is renally eliminated; avoid or monitor anti-Xa closely if CrCl <30 mL/min.
  • Anti-Xa Monitoring (if indicated):
    • Therapeutic range: 0.5–1.0 IU/mL (q24h dosing) or 0.5–1.5 IU/mL (q12h dosing).
  • Elderly: Increased bleeding risk due to lower renal reserve and comorbidities.
  • Weight: Treatment doses are weight-based, but capped at 18,000 IU/day.
  • Pediatrics: Use weight-based dosing; limited data, monitoring essential.
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