Methodological note
This page combines two levels of information that must be kept separate. The first is that of clinical guidelines (Italian and international scientific societies, randomised trials), which guide the choice between drug classes according to the diagnosis and the patient's condition. The second is that of the summaries of product characteristics (SmPC) of the individual medicines, which set out licensed indications, doses and contraindications that are legally binding regardless of what the guidelines suggest.
The numerical thresholds for creatinine clearance, body weight and treatment duration given below are indicative values, useful for guiding the choice: always check the current SmPC of each generic/originator product in the database of the Italian Medicines Agency (AIFA), as they may vary slightly between products and over time.
DOACs — direct oral anticoagulants
Licensed indication
Rivaroxaban, apixaban, edoxaban and dabigatran are licensed for the treatment of DVT and pulmonary embolism and for the prevention of recurrence, as an alternative to vitamin K antagonists. They do not require routine INR monitoring.
Dosing regimen (SmPC)
| Drug | Initial phase | Maintenance | SmPC notes |
|---|---|---|---|
| Rivaroxaban | 15 mg twice daily, 21 days | 20 mg once daily | Take with food; no parenteral lead-in ( single-drug) |
| Apixaban | 10 mg twice daily, 7 days | 5 mg twice daily | Reduce to 2.5 mg twice daily after 6 months if continued to prevent recurrence |
| Edoxaban | LMWH 5–10 days | 60 mg once daily (30 mg if reduced dose) | Requires parenteral lead-in; reduced dose if weight ≤60 kg, CrCl 15–50 mL/min or P-gp inhibitors |
| Dabigatran | LMWH 5–10 days | 150 mg twice daily (110 mg twice daily in selected patients) | Requires parenteral lead-in; 110 mg twice daily if aged ≥ 80 or on verapamil, to be considered in other selected patients |
Indicative regimens according to the SmPC; rivaroxaban and apixaban do not require an initial parenteral lead-in ( single-drugapproach), whereas edoxaban and dabigatran require one for 5–10 days.
Contraindications and renal thresholds (SmPC)
| Drug | Renal caution/contraindication threshold |
|---|---|
| Rivaroxaban | Caution with CrCl 15–29 mL/min; not recommended below 15 mL/min |
| Apixaban | No adjustment down to CrCl 15 mL/min; limited data below this threshold and in dialysis |
| Edoxaban | Dose reduced to 30 mg if CrCl 15–50 mL/min; not recommended below 15 mL/min |
| Dabigatran | Contraindicated with CrCl <30 mL/min |
Indicative thresholds: always check the current SmPC, as they may differ slightly between generic products and later versions of the package leaflet.
LMWH — low-molecular-weight heparins
Licensed indication
Enoxaparin, nadroparin and dalteparin are licensed for the treatment of DVT and pulmonary embolism, as well as for the prophylaxis of venous thromboembolism. They remain the reference option when a parenteral route is needed or when DOACs are not suitable.
Dosing regimen (SmPC)
| Drug | Therapeutic dose (DVT) |
|---|---|
| Enoxaparin | 1 mg/kg twice daily or 1.5 mg/kg once daily |
| Nadroparin | 85.5 IU anti-Xa/kg twice daily |
| Dalteparin | 100 IU/kg twice daily or 200 IU/kg once daily |
Doses calculated on actual body weight according to the SmPC; in severe renal impairment a once-daily regimen with anti-Xa monitoring is generally indicated.
Fondaparinux (Arixtra)
Licensed indication
Fondaparinux is a synthetic pentasaccharide, a selective factor Xa inhibitor. It is licensed both for the treatment of DVT and pulmonary embolism and — at a lower dose — for the treatment of intermediate-to-high-risk lower-limb SVT, on the basis of the CALISTO trial.
Dosing regimen (SmPC)
| Indication | Dose | Duration |
|---|---|---|
| DVT / pulmonary embolism | 7.5 mg once daily s.c. (5 mg if <50 kg; 10 mg if >100 kg) | At least 5 days, then overlap with oral therapy |
| Lower-limb SVT | 2.5 mg once daily s.c., fixed dose | 45 days |
In SVT the dose is fixed and independent of body weight, unlike the DVT regimen, which follows weight bands.
Superficial vein thrombosis (SVT)
The treatment choice depends on the distance of the thrombus from the saphenofemoral or saphenopopliteal junction and on the length of the segment involved.
- High risk — thrombus within 3 cm of the junction: treat as DVT, with therapeutic-dose anticoagulation (ESVS 2021, class I). The duration is not uniformly defined: usually 3 months, as for proximal DVT.
- Intermediate risk — more than 3 cm from the junction, segment ≥5 cm: licensed indication for fondaparinux 2.5 mg daily for 45 days (CALISTO trial); rivaroxaban 10 mg daily (SURPRISE trial) and LMWH remain alternatives with a lower level of specific evidence.
- Low risk — segment <5 cm, away from the junction: management with NSAIDs, compression stockings and clinical surveillance; anticoagulation is not routine.
Deep vein thrombosis (DVT)
For DVT, full therapeutic anticoagulation is indicated after imaging confirmation. In Italy, AIFA Note 101 identifies DOACs as the preferred option over vitamin K antagonists, except in specific situations where they are not suitable.
- Proximal DVT, standard patient — DOACs as first choice (rivaroxaban or apixaban without lead-in; dabigatran or edoxaban with a 5–10-day parenteral lead-in).
- Isolated distal DVT, low risk — in selected patients, some guidelines accept serial ultrasound surveillance alone as an alternative to full treatment.
- DVT with pulmonary embolism — same indication as proximal DVT, once haemodynamic instability or high-risk PE has been excluded; these require a dedicated in-hospital pathway.
- DVT and active cancer — LMWH is an established option; apixaban, edoxaban and rivaroxaban are validated alternatives in selected patients, with caution in gastrointestinal or genitourinary cancers because of the bleeding risk.
Special populations and contraindications
| Condition | Preferred option | Avoid / caution |
|---|---|---|
| Severe renal impairment | LMWH with dose adjustment and anti-Xa monitoring | Full-dose fondaparinux and dabigatran contraindicated below the SmPC clearance thresholds |
| Severe hepatic impairment | LMWH, with attention to the bleeding risk from coagulopathy | DOACs generally not recommended in liver disease with associated coagulopathy |
| Pregnancy / breastfeeding | LMWH | DOACs and fondaparinux not recommended because of the lack of established safety data |
| Active cancer | LMWH or apixaban/edoxaban/rivaroxaban in selected patients | Caution in gastrointestinal or genitourinary cancers |
| Antiphospholipid syndrome (triple-positive) | Vitamin K antagonist with parenteral overlap | DOACs not recommended in this subgroup |
| Known or suspected HIT | Fondaparinux | LMWH and unfractionated heparin contraindicated |
| Body weight < 50 kg | LMWH dosed on actual weight | Increased bleeding risk; reduced-dose edoxaban; limited experience with dabigatran — see §7 |
| Severe obesity (> 120 kg or BMI > 40) | Standard-dose rivaroxaban or apixaban, or LMWH dosed on actual weight | Edoxaban and dabigatran not suggested because of insufficient data — see §7 |
| Recent bariatric surgery | LMWH or fondaparinux (parenteral route) | DOACs: unpredictable oral absorption in the first months after surgery |
Summary guidance: the decision must always be individualised, taking into account several conditions when they coexist in the same patient.
Body weight: bands and dose adjustments
Body weight is neither a contraindication nor a generic «caution»: in most cases it is a dosing parameter. The thresholds that matter differ for each class and do not coincide, so a single «extreme weight» item is of no practical use.
Weight bands and how the three classes behave
| Band | DOACs | LMWH | Fondaparinux (DVT/PE) |
|---|---|---|---|
| < 50 kg | Increased bleeding risk. Rivaroxaban and apixaban: full dose unchanged in VTE. Edoxaban 30 mg once daily. Dabigatran: limited experience | Dose on actual weight; check that it matches the prefilled syringe; anti-Xa if renal impairment | 5 mg once daily |
| 50–60 kg | Edoxaban only: 30 mg once daily (SmPC threshold ≤ 60 kg). No change for the other drugs | Dose on actual weight | 7.5 mg once daily |
| 60–100 kg | Standard regimens, no weight-related adjustment | Dose on actual weight | 7.5 mg once daily |
| 100–120 kg | Standard regimens, no weight-related caution | Dose on actual weight | 10 mg once daily |
| > 120 kg or BMI > 40 | Rivaroxaban and apixaban at standard doses, without measuring drug levels (ISTH SSC 2021). Edoxaban and dabigatran not suggested | Dose on actual weight, without a dose cap; peak anti-Xa in the highest bands | 10 mg once daily (limited data) |
| > 150 kg or BMI > 50 | Scarce data even for rivaroxaban and apixaban: consider LMWH or a VKA, with the INR as a verifiable parameter | Less predictable effect: peak anti-Xa monitoring recommended | 10 mg once daily (very limited data) |
In SVT the fondaparinux regimen is a fixed dose of 2.5 mg daily regardless of weight: the bands in the table apply to DVT and pulmonary embolism. Below 50 kg, experience with the SVT regimen is limited and bleeding risk is increased: check the SmPC.
Cross-class summary
A summary of the three classes, useful as a quick reminder before prescribing.
| Class | Route | Monitoring | Strength | Main limitation |
|---|---|---|---|---|
| DOACs | Oral | Not routinely required | No injections; easier adherence | Contraindicated in pregnancy, APS, severe renal impairment |
| LMWH | Subcutaneous | Anti-Xa in selected cases | Drug of choice in pregnancy; extensive experience | Contraindicated in HIT; daily injections |
| Fondaparinux | Subcutaneous | Not routinely required | Does not cause HIT; specific indication in SVT | Contraindicated in severe renal impairment |
For case-by-case guidance based on the diagnosis and the individual patient's conditions, use the interactive anticoagulant selector.
Sources
The main sources used for this summary. For exact doses and the full context, refer to the original documents and the current SmPCs.
- AIFA Note 101. Prescription of oral anticoagulant therapy (in Italian;aifa.gov.it).
- Italian DVT guidelines. SIAPAV, SISET, CIF, FCSA, SIMEU, SIMG — Guidelines for the diagnosis and treatment of deep vein thrombosis (in Italian).
- SVT guidelines. SIAPAV — Common practice in the treatment of superficial vein thrombosis of the saphenofemoral junction (in Italian).
- CALISTO trial. Fondaparinux vs placebo in lower-limb SVT (N Engl J Med 2010).
- SURPRISE trial. Fondaparinux vs rivaroxaban in SVT.
- ISTH SSC guidance 2021. Martin KA, Beyer-Westendorf J, Davidson BL, Huisman MV, Sandset PM, Moll S — Use of direct oral anticoagulants in patients with obesity for treatment and prevention of venous thromboembolism: updated communication from the ISTH SSC Subcommittee on Control of Anticoagulation (J Thromb Haemost 2021), an update of the previous 2016 guidance on weight and BMI thresholds.
- Summaries of product characteristics (SmPC). Package leaflets and summaries of product characteristics of the individual medicines — database of the Italian Medicines Agency (AIFA).