Pharmacotherapeutic group: sclerosing agents for local injection, ATC code: C05BB02
Lauromacrogol 400 (also known as polidocanol) is the active ingredient of Aethoxysklerol, has world-wide well-established use for sclerotherapy treatment of varicose veins.
Both primary and secondary nonclinical pharmacodynamic studies show that the pharmacological profile of lauromacrogol 400 is characterized by its local effects on cell membranes and the associated, locally confined, damage to tissue. This pharmacodynamic activity results in the desired sclerosing effect of blood vessels if lauromacrogol 400 is administered correctly, but may cause unintended tissue damage and subsequent adverse reactions if the recommended application procedure is not followed.
Lauromacrogol 400 has a concentration and volume dependent effect on the endothelium of blood vessels and possibly additional layers of the vein wall. In the long term, the affected veins are transformed into a fibrous cord. The result of sclerotherapy is equivalent to the surgical removal of a varicose vein. Application of compression following sclerotherapy of varicose veins compresses the damaged vein walls so that excessive thrombus formation and recanalisation of the initially formed parietal thrombus is prevented. This gives rise to the desired transformation into fibrous tissue and hence sclerosis. The main pharmacodynamic effect of lauromacrogol 400 - the induction of tissue damage by interacting with the lipid double layer of cells - diminishes with increasing distance from the site of injection. The pharmacological action of lauromacrogol 400 is therefore considered to be locally restricted.
When converted to a microfoam, lauromacrogol 400 is very effective at treating small, medium and large varicose veins. The microfoam has more time to act compared to the liquid form, using a smaller quantity. However, additional precautions and contraindications are applicable and some adverse events are more frequent following microfoam sclerotherapy compared to liquid sclerotherapy.
⚠️ Warnings
No special requirements for disposal.
Preparation of the Microfoam
Preparation of the microfoam using the Tessari and Dual Syringe System (DSS) techniques, respectively, is described below. Other suitable techniques may also be used.
The foam must be prepared just before use and administered by a physician appropriately trained in the correct generation and administration of foam. Strict aseptic technique must be maintained while manufacturing the foam.
The quality of microfoam depends on specific criteria:
a) Concentration of lauromacrogol 400: In order to obtain a very fine-bubbled and stable microfoam, a concentration of 10-30 mg/ml must be used.
b) Proportion of liquid to gas: In general, this proportion is 1 volume of liquid for 4 volumes of gas.
c) Macroscopic appearance: Observe the macroscopic appearance of the microfoam in the syringe: It must be homogenous and fine-bubbled. No unmixed liquid or gas should be visible.
d) Maximum time between preparation and injection: Inject the microfoam soon after preparation (within 60 seconds).
Filling of the syringes for both foam preparation methods
Note: Syringes containing siliconized components produce a less stable foam and their use should be minimised. As two sterile syringes are needed to create the foam, only the second syringe should have a rubber plunger as this will aid a smooth injection.
To create the foam 2 ml of liquid sclerosant is drawn into the first syringe (without a rubber plunger). The second syringe (with a rubber plunger) is fixed to a 0.2 µm sterile filter and 8 ml of sterile air is drawn up.
Preparation of sclerosing microfoam with Tessari technique:
The syringes are firmly connected to a sterile three-way tap/valve (Fig. 1).
Foam generation is performed by mixing sclerosant and the air by moving the plungers of both syringes completely forward and backward approximately 20 times under high pressure on both syringes (Fig. 2 and 3). A smooth, consistent foam is obtained. The syringe with the rubber plunger is filled with foam and is then removed from the three-way valve. The vein is injected immediately (Fig. 4).
Preparation of sclerosing microfoam with DSS (Double Syringe System):
The syringes are firmly connected to a sterile Luer Lock female-female adapter (Fig. 5). Foam generation is performed by mixing sclerosant and the air by moving the plungers of both syringes completely forward and backward 5 times with a short, firm thumb pressure of both hands, so that the pumping must be done against a resistance (Fig. 6 and 7). This is followed by 7 quick forward and backward movements without additional pressure to get a homogenous foam. The syringe with the rubber plunger is filled with foam and is then removed from the adapter. The vein is injected immediately (Fig. 8).
PillsCard reference image