Sclerosing Agents for Varicose Vein Treatment
For varicose veins, sclerosing agents such as polidocanol or sodium tetradecyl sulfate are injected directly into the vein to cause fibrosis and obliteration, with the specific agent and concentration determined by vein size.
Sclerosing Agents and Concentrations by Vein Size
Small Veins (Spider Veins ≤1 mm)
- Polidocanol 0.5% is FDA-approved for spider veins ≤1 mm in diameter 1
- Inject 0.1 to 0.3 mL per injection site, with a maximum of 10 mL per treatment session 1
Medium Veins (Reticular Veins 1-3 mm)
- Polidocanol 1% is FDA-approved for reticular veins 1 to 3 mm in diameter 1
- Use 0.1 to 0.3 mL per injection into each varicose vein 1
- Alternative agents include sodium tetradecyl sulfate 0.25-0.5% for veins in this size range 2, 3
Larger Veins (≥2.5 mm)
- Foam sclerotherapy with polidocanol 1-3% is recommended for veins ≥2.5 mm in diameter 4, 5
- Foam sclerotherapy achieves 72-89% occlusion rates at 1 year for appropriately sized veins 4, 5
- Sodium tetradecyl sulfate can also be used, with foam preparations showing higher efficacy than liquid formulations 6, 3
Common Sclerosing Agents Used in Practice
The most commonly used sclerosants in the United States include 2:
- Polidocanol (available as Asclera® and Varithena®)
- Sodium tetradecyl sulfate
- 23.4% hypertonic saline
- Combination of 25% dextrose with 10% saline
Foam vs. Liquid Sclerotherapy
Foam sclerotherapy offers advantages over liquid sclerotherapy for larger veins 6, 7:
- Higher elimination of reflux compared to liquid formulations 5
- Better contact with vessel walls in larger diameter veins 6
- Foam preparations can be created using the Tessari method or Monfreux technique 6
- Safe foam volume should not exceed 3 mL per injection site 6
Treatment Algorithm Based on Vein Size
For veins <2.5 mm:
- Liquid sclerotherapy is appropriate 4
- Vessels <2.0 mm have only 16% primary patency at 3 months, indicating poor outcomes with sclerotherapy 5
For veins 2.5-4.4 mm:
- Foam sclerotherapy is the evidence-based treatment 4, 5
- This is preferred over endovenous thermal ablation for this size range 4
For veins ≥4.5 mm with documented reflux:
- Endovenous thermal ablation (radiofrequency or laser) is first-line treatment 4, 5, 8
- Foam sclerotherapy may be used as adjunctive therapy for tributary veins 5
Important Clinical Considerations
Ultrasound guidance is essential for treating larger veins and perforators to ensure accurate visualization and proper sclerosant delivery 5, 2
Treatment should proceed from proximal to distal and largest to smallest vein, based on a reflux map developed from duplex ultrasound 2
Post-treatment compression is essential to optimize outcomes and reduce complications 8
Safety Profile
Both polidocanol and sodium tetradecyl sulfate demonstrate similar safety profiles 3:
- Deep vein thrombosis occurs in approximately 0.3% of cases 5, 8
- Common minor complications include phlebitis, telangiectasias, and residual pigmentation 5
- Polidocanol may have slightly increased DVT rates compared to placebo (RR 5.10) 7
Contraindications
Sclerotherapy is contraindicated in 1:
- Known allergies to polidocanol or other sclerosants
- Patients with acute thromboembolic diseases
- Intra-arterial injection must be avoided to prevent tissue ischemia and necrosis 1