DalteparinEdit

Dalteparin is a clinically important anticoagulant in the family of low molecular weight heparins (LMWHs). It is used to prevent and treat thromboembolic disorders by disrupting the body's normal clot-forming processes. Dalteparin works by enhancing the activity of the natural anticoagulant antithrombin III, which in turn inhibits key enzymes of the coagulation cascade, most notably factor Xa and, to a lesser extent, thrombin. Compared with unfractionated heparin, dalteparin and its LMWH cousins offer more predictable pharmacokinetics, simplified dosing regimens, and a notably lower risk of heparin-induced thrombocytopenia (HIT), making it a mainstay of modern perioperative and medical thromboprophylaxis. It is administered by subcutaneous injection, often on a daily schedule, and is marketed under the trade name Fragmin, among others, in various regions.

Dalteparin has a broad spectrum of indications, spanning surgical prophylaxis, treatment of acute thromboembolic events, and specific clinical situations such as cancer-associated thrombosis. Its use is grounded in extensive clinical experience and multiple randomized trials that compare LMWHs to unfractionated heparin and to other anticoagulant strategies. The drug’s predictable response allows many patients to be treated without routine laboratory monitoring, although clinicians may measure anti-Xa activity in certain populations, such as those with renal impairment, extreme body weight, pregnancy, or pediatric patients.

Medical uses

Prophylaxis of venous thromboembolism after major surgery, including orthopedic procedures (hip and knee replacements) and abdominal surgery. In these settings, dalteparin reduces the incidence of postoperative deep vein thrombosis deep vein thrombosis and can lower the risk of pulmonary embolism pulmonary embolism.
Treatment of acute venous thromboembolism, including deep vein thrombosis and some cases of pulmonary embolism, particularly when rapid and reliable anticoagulation is desired and monitoring needs are minimized.
Cancer-associated thrombosis, where dalteparin has been studied as a preferred option in several trials, showing favorable outcomes in preventing recurrent thrombosis compared with some oral agents. This has made dalteparin a commonly discussed option in the broader topic of cancer-associated thrombosis.
Bridging anticoagulation in patients transitioning between therapies, such as prior to elective procedures or when adjusting oral anticoagulants like warfarin.

Certain populations and clinical situations may require adjustments or alternative agents. In renal impairment, for instance, the pharmacokinetics of dalteparin can be altered, and clinicians may monitor anti-Xa levels or switch to alternative regimens. Dalteparin’s use is also weighed against risks of major bleeding and against the evolving landscape of anticoagulants, including direct oral anticoagulants (DOACs) Direct oral anticoagulants.

Pharmacology and pharmacokinetics

Mechanism of action: Dalteparin exerts its anticoagulant effect primarily by potentiating the activity of antithrombin III, inhibiting factor Xa and, to a lesser degree, thrombin (factor IIa). The higher anti-Xa activity relative to IIa activity is a characteristic feature of LMWHs and contributes to their favorable safety profile.
Pharmacokinetics: LMWHs, including dalteparin, typically have more predictable absorption and dose-response relationships than unfractionated heparin, enabling fixed, weight-based dosing without routine laboratory monitoring in most patients. Peak activity occurs after subcutaneous administration, and the duration of effect supports once-daily or twice-daily dosing regimens in many indications.
Administration: Given by subcutaneous injection, usually in a hospital or outpatient setting. Dose depends on the indication (prophylaxis vs treatment) and patient factors such as weight and renal function.
Comparators: In the anticoagulation landscape, dalteparin sits alongside other LMWHs, unfractionated heparin, and, for certain indications, DOACs. Each option has trade-offs in terms of monitoring needs, bleeding risk, reversibility, and cost. See low molecular weight heparin and Direct oral anticoagulants for broader context.

Dosing and administration

Dalteparin dosing varies by clinical scenario: - Prophylaxis after surgery: typically a fixed dose (for example, in many guidelines around 2500–5000 international units daily, adjusted by patient factors) to reduce the risk of postoperative venous thromboembolism. - Treatment of established venous thromboembolism: often weight-based, such as around 200 international units per kilogram of body weight per day, with adjustments as clinically indicated, divided into one or two injections per day. - Bridging to oral anticoagulation: dalteparin can be used to bridge therapy when transitioning to agents such as warfarin or other long-term anticoagulants.

Clinical practice guidelines may differ in exact regimens, and physicians consider patient-specific factors, including renal function and bleeding risk, when selecting dosing. For patients with renal impairment or other special considerations, monitoring with anti-Xa activity or choosing alternative anticoagulation strategies may be appropriate.

Contraindications and adverse effects

Contraindications: Active major bleeding, known hypersensitivity to dalteparin or other LMWHs, severe bleeding diatheses, and certain conditions where bleeding risk is unacceptable. Caution is advised in patients with major surgery involving the central nervous system or eyes due to risk of hematoma in settings of neuraxial anesthesia or invasive procedures.
HIT risk: Dalteparin carries a risk of heparin-induced thrombocytopenia, though this risk is generally lower with LMWHs than with unfractionated heparin. Clinicians monitor for platelet count declines and adjust therapy if HIT is suspected.
Other adverse effects: Bleeding of various degrees is the most important risk. Local injection site reactions, osteoporosis with long-term use (less common with LMWH than with unfractionated heparin), and rare hypersensitivity reactions may occur. Renal function and concomitant medications (such as antiplatelet agents) influence bleeding risk.
Special considerations: Epidural or spinal anesthesia and invasive procedures require careful timing of dalteparin administration to minimize the risk of spinal or epidural hematoma.

Interactions and considerations

Drug interactions: Concomitant use with other anticoagulants or antiplatelet agents increases bleeding risk. Clinicians assess the cumulative effect on hemostasis when combining therapies.
Monitoring: Routine laboratory monitoring is not required for most patients on dalteparin, but anti-Xa activity may be used in certain populations (renal impairment, obesity, pregnancy, pediatrics) to guide dosing. In the setting of pregnancy, dalteparin is generally preferred over vitamin K antagonists for anticoagulation in many cases, due to safety considerations for the fetus.
Reversal: In the event of major bleeding, reversal strategies may include administration of protamine sulfate, though the reversal is not always complete and depends on timing and dosing of dalteparin.

History and regulation

Dalteparin and other LMWHs emerged as a refinement of unfractionated heparin therapy, offering easier administration and improved safety profiles. Fragmin is the trade name most closely associated with dalteparin in many markets, and the product has been studied extensively in the prevention and treatment of thromboembolic disease. Regulatory status varies by country, but the core therapeutic niche—subcutaneous anticoagulation with a favorable safety and convenience profile—remains central to its clinical use. The broader class, including other LMWHs and newer anticoagulants, is integrated into guidelines that reflect ongoing advances in thrombosis management and risk stratification.

Controversies and debates

LMWH versus DOACs in cancer-associated thrombosis: In the cancer setting, dalteparin has long been evaluated as a preferred option because of evidence showing lower recurrence of venous thromboembolism compared with some oral agents. However, newer data on direct oral anticoagulants (DOACs) have shifted practice in some centers, with debates centering on bleeding risk (notably gastrointestinal and genitourinary bleeding in certain cancer types), patient convenience, and cost. Proponents of LMWH highlight trial results and quality-of-life considerations for patients with cancer, arguing that dalteparin offers reliable protection with a well-characterized safety profile. Critics of wading into DOACs point to less robust historical evidence in cancer and the need for careful patient selection.
Cost and access: The price of dalteparin and the logistics of weekly or daily injections can be a barrier in some health systems or private plans. Advocates of cost-conscious care argue for balancing drug costs with clinical outcomes, encouraging pathways that maximize value—whether through selecting the most effective agent for a given cancer type, adopting generic or biosimilar options where appropriate, or leveraging guideline-concordant use to avoid overtreatment.
Monitoring versus convenience: While dalteparin generally requires less monitoring than some alternatives, certain patients still benefit from anti-Xa monitoring in specific scenarios. This creates a debate about where fixed dosing suffices and where individualized monitoring adds meaningful safety or efficacy benefits, especially in high-risk populations or when transitioning to long-term therapy.