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Cantharidin is a blistering agent (vesicant) from blister beetles that Bayview compounds to a prescriber's order.
Cantharidin is a vesicant secreted by many species of blister beetle, most notably the Spanish fly (Lytta vesicatoria).[2] It is used in dermatology for its ability to cause blistering of the skin. A cantharidin topical solution is FDA-approved for the treatment of molluscum contagiosum in patients 2 years of age and older,[1] and topical cantharidin is also used off-label for warts.[3] Cantharidin inhibits protein phosphatases 1 and 2A,[2] although its mechanism of action in treating molluscum contagiosum is unknown.[1]
Cantharidin is applied directly to the affected lesions for topical use only.[1][4] Care is needed to avoid unintended exposure, because contact with the eyes can cause serious injury and oral ingestion can cause life-threatening toxicity.[1] Cantharidin is on FDA's list of bulk drug substances that can be used in compounding under section 503A, for topical use only.[4]
Because of its potency, cantharidin should be handled with care, and it is applied by trained healthcare professionals.[1] Prescribers should be aware of its adverse effects: local skin reactions such as blistering, pain, itching, redness, scabbing, and skin discoloration are very common at the application site.[1][3] Patient education on post-application care is important; the approved product is washed off with soap and water 24 hours after treatment.[1]
Bayview Pharmacy compounds cantharidin preparations on a prescriber's order.
Compounded at Bayview
Patient guides for the preparations we make most often. Each one is compounded to order and requires a prescription.
For prescribers
Every preparation in our formulary that contains this ingredient. Strength, base and dose form are set by the prescription.
In the office. Cantharidin is a blistering agent, so a trained provider applies it precisely to each lesion and tells you exactly when to wash it off at home, typically within a few hours. It is never dispensed for patients to apply themselves. Bayview compounds it on a patient-specific prescription for the treating provider.
Used as intended, applied only to the lesions by a provider, the effects are localized (blistering, redness, tenderness). Cantharidin is highly toxic if swallowed and must be kept away from the eyes and mucous membranes, which is one reason it is applied by a clinician rather than at home.
No. Bayview is a 503A compounding pharmacy, so we prepare cantharidin pursuant to a prescription for an individual patient. Bulk stock for general office use is the role of a 503B outsourcing facility, which Bayview is not.
No. A separate proprietary cantharidin product is FDA-approved for molluscum, but the compounded preparations Bayview makes are not FDA-approved. They are prepared by a licensed pharmacy pursuant to a prescription.
Other salt forms of this molecule, and ingredients commonly compounded alongside it.
This page describes an active pharmaceutical ingredient, not a finished drug product. Bayview Pharmacy compounds preparations containing it only on a prescriber's order for an individual patient.
Compounded preparations are not FDA-approved, and the FDA has not evaluated them for safety, effectiveness, or manufacturing quality. Nothing on this page is a claim that any preparation is effective for any condition.
A valid prescription is required. Availability depends on Bayview's licensure in your state. This page is general information, not medical advice — discuss your situation with a licensed healthcare provider.
Our pharmacists work with prescribers to build preparations around a patient's dose, form and tolerances. Ask us what is possible with this ingredient.
