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Laureth-9 (polidocanol)

Generic name: laureth-9 (polidocanol) [ LAWR-eth-9 ]
Brand names: Asclera, Varithena
Dosage forms: injectable foam (1%), injectable kit (1%), injectable solution (0.5%; 1%)
Drug class: Sclerosing agents

Medically reviewed by on Oct 17, 2022. Written by Cerner Multum.

What is laureth-9?

Laureth-9 is a sclerosing (skler-OH-sing) agent. It works by increasing the formation of blood clots and scar tissue inside certain types of veins. This helps decrease dilation of enlarged veins.

Laureth-9 is used to treat small uncomplicated spider veins and varicose veins in the legs. Laureth-9 will not treat varicose veins that are larger than 3 millimeters (about one-eighth of an inch) in diameter.

Laureth-9 is not a cure for varicose veins and the effects of this medication may not be permanent.

Laureth-9 may also be used for purposes not listed in this medication guide.

Laureth-9 side effects

Get emergency medical help if you have any of these signs of an allergic reaction: hives; sneezing, runny nose, difficult breathing; swelling of your face, lips, tongue, or throat.

Tell your caregivers at once if you have a serious side effect such as:

  • severe pain, burning, or other irritation in your leg;

  • discoloration or skin changes where an injection was given;

  • sudden severe headache, confusion, problems with vision, speech, or balance;

  • pain, swelling, warmth, or redness in one or both legs;

  • severe numbness that does not go away;

  • trouble breathing, pounding heartbeats or fluttering in your chest; or

  • confusion, feeling like you might pass out.

Common side effects of laureth-9 may include:

  • mild numbness or tingling;

  • mild headache, dizziness;

  • increased hair growth on the treated leg; or

  • mild pain or warmth, mild itching, or slight bruising where an injection was given.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.


You should not receive this medication if you have a blood clot disorder such as deep vein thrombosis (DVT), swelling of a vein caused by a blood clot, or Buerger's disease.

Before taking this medicine

You should not receive laureth-9 if you are allergic to laureth-9, lauromacrogol 400, or polidocanol, or if you have:

  • a blood clot disorder such as deep vein thrombosis (DVT) or thrombophlebitis (swelling of a vein caused by a blood clot); or

  • Buerger's disease (a blood clotting disorder affecting the arms and legs).

To make sure laureth-9 is safe for you, tell your doctor about all of your medical conditions or allergies.

FDA pregnancy category C. It is not known whether laureth-9 will harm an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant while receiving this medicine.

It is not known whether laureth-9 passes into breast milk or if it could harm a nursing baby. You should not breast-feed while you are using laureth-9.

How is laureth-9 given?

Laureth-9 is injected with a small needle directly into a varicose or spider vein. You will receive this injection in a clinic or hospital setting.

The number of injections you receive will depend on the number of spider or varicose veins being treated.

Laureth-9 must be injected slowly into the vein. Your caregivers will apply slight pressure to the vein during an injection.

Tell your caregivers if you feel any burning, pain, or swelling around the IV needle when laureth-9 is injected. You will be watched closely after your injection, to make sure this medication is not causing harmful effects.

After the needle is removed from the vein, a compression bandage or stocking will be placed on the leg to prevent blood clots from forming.

When your treatment session is finished, your caregivers may want you to walk around for 15 or 20 minutes. Your doctor may instruct you to take daily walks for a few days after your treatment with laureth-9.

You may need to wear compression stockings for several days or weeks after your treatment. Carefully follow your doctor's instructions about caring for yourself after receiving this medication.

You may need additional treatment sessions with laureth-9 to best treat the varicose vein. At least 1 week should pass between treatment sessions.

What happens if I miss a dose?

Because you will receive laureth-9 in a clinical setting, you are not likely to miss a dose.

What happens if I overdose?

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

Overdose may cause severe skin reaction such as burning, discoloration or tissue damage where an injection was given.

What should I avoid after receiving laureth-9?

Avoid heavy or strenuous exercise for 2 or 3 days after your treatment. Also avoid sitting for long periods of time, such as long-distance travel in a car or on an airplane.

Also avoid exposure to sunlight, tanning beds, hot tubs, or saunas for 2 or 3 days after your treatment.

Do not use ice or a heating pad on your treated leg without your doctor's advice.

What other drugs will affect laureth-9?

It is not likely that other drugs you take orally or inject will have an effect on laureth-9 used to treat varicose veins. But many drugs can interact with each other. Tell your doctor about all medicines you use. This includes prescription, over-the-counter, vitamin, and herbal products. Do not start a new medication without telling your doctor.

Further information

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use this medication only for the indication prescribed.

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.