Answer
Fibrovein (sodium tetradecyl sulfate) foam displaces blood, giving the sclerosant more time to act on the vein endothelium than the liquid form.
Sources for this answer
- Fibrovein 3%, 1%, 0.5%, 0.2%STD Pharmaceutical Products Ltd · emc · SmPC §5.1 Pharmacodynamic properties · Version 3Document updated
Sources checked