Cantharidin is a chemical derived from the green blister
Your doctor "paints" cantharidin on your
wart and covers it with a bandage. This is generally
painless. The cantharidin causes the skin under the wart to blister, lifting
the wart off the skin. When the blister dries, the wart comes off with the
blistered skin. You may feel some pain when the skin blisters. When you see
your doctor again, he or she will remove the dead skin and the
wart. If the wart isn't gone after one treatment, you may need another
Cantharidin is sometimes used if salicylic acid or freezing a wart
with liquid nitrogen (cryotherapy) has not successfully eliminated it.
Cantharidin should not be used:
Cantharidin is an effective treatment for warts.1 After the wart is gone, there usually is no scarring.
Cantharidin also may be used in children.
All medicines have side effects. But many people don't feel the side effects, or they are able to deal with them. Ask your pharmacist about the side effects of each medicine you take. Side effects are also listed in the information that comes with your medicine.
Here are some important things to think about:
Call 911 or other emergency services right away if you have:
Call your doctor if you have:
Common side effects of this medicine include:
See Drug Reference for a full list of side effects. (Drug Reference
is not available in all systems.)
Cantharidin can be used to treat warts that are resistant to other
forms of treatment. It is not approved by the U.S. Food and Drug Administration
(FDA) for the treatment of warts.
Cantharidin is not well researched or widely used.
Cantharidin has a low risk of scarring.
Medicine is one of the many tools your doctor has to treat a health problem. Taking medicine as your doctor suggests will improve your health and may prevent future problems. If you don't take your medicines properly, you may be putting your health (and perhaps your life) at risk.
There are many reasons why people have trouble taking their medicine. But in most cases, there is something you can do. For suggestions on how to work around common problems, see the topic Taking Medicines as Prescribed.
Do not use this medicine if you are pregnant, breast-feeding, or planning to get pregnant. If you need to use this medicine, talk to your doctor about how you can prevent pregnancy.
Follow-up care is a key part of your treatment and safety. Be sure to make and go to all appointments, and call your doctor if you are having problems. It's also a good idea to know your test results and keep a list of the medicines you take.
Complete the new medication information form (PDF)(What is a PDF document?) to help you understand this medication.
CitationsHabif TP, et al. (2011). Herpes simplex section of Viral infections. In Skin Disease: Diagnosis and Treatment, 3rd ed., pp. 224–229. Edinburgh: Saunders.
September 7, 2012
Patrice Burgess, MD - Family Medicine & E. Gregory Thompson, MD - Internal Medicine
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Last modified on: 28 September 2013