Cantharidin

The mechanism of action of cantharidin in the treatment of molluscum contagiosum is unknown.

• YCANTH is indicated for the topical treatment of molluscum contagiosum in adult and pediatric patients 2 years of age and older. YCANTH is indicated for the topical treatment of molluscum contagiosum in adult and pediatric patients 2 years of age and older.

• None Nonecontraindicated

All healthcare professionals should receive instruction and training prior to preparation and administration of YCANTH. ( 2.1 ) For topical use only. Not for oral, mucosal, or ophthalmic use. ( 2.1 ) Apply a single application directly to each lesion every 3 weeks as needed. ( 2.2 ) Do not use more than two applicators during a single treatment session. ( 2.2 ) Remove with soap and water 24 hours after treatment. ( 2.2 ) For additional instructions on preparation and administration of YCANTH, see Full Prescribing Information. ( 2.1 , 2.2 , 2.3 ) 2.1 Important Administration Instructions All healthcare professionals should receive instruction and training prior to preparation and administration of YCANTH. YCANTH is for topical use only. YCANTH is not for oral, mucosal, or ophthalmic use. Avoid contact with the treatment area, including oral contact, after YCANTH treatment. Do not apply YCANTH near the eyes [see Warnings and Precautions (5.1) , Overdosage (10) ] . If YCANTH contacts any unintended surface, including healthy skin, immediately remove by wiping with a cotton swab or gauze. Avoid other topical products on treated areas until 24 hours after YCANTH treatment or until washing [see Warnings and Precautions (5.2) ]. Avoid fire, flame or smoking near lesion(s) during treatment [see Warnings and Precautions (5.3) ] . 2.2 Dosage and Administration Overview Regarding YCANTH dosage and administration: Use nitrile or vinyl gloves and eye protection during preparation and administration. Apply topically as a single application to cover each lesion.

Toxicities Associated with Inappropriate Administration: Life threatening or fatal toxicities can occur if administered orally. Avoid contact with the treatment area, including oral contact, after treatment. Ocular toxicity can occur if YCANTH comes in contact with eyes. If YCANTH gets in eyes, flush eyes with water for at least 15 minutes. ( 5.1 ) Local Skin Reactions : Reactions at the application site have included vesiculation, pruritus, pain, discoloration, and erythema. Avoid application near eyes and mucosal tissue, and to healthy skin. If YCANTH contacts any unintended surface, or healthy skin, immediately remove. If severe local skin reactions occur, remove prior to 24 hours after treatment. ( 5.2 ) Flammability : YCANTH is flammable, even after drying. Avoid fire, flame or smoking near lesion(s) during treatment and after application until removed. ( 5.3 ) 5.1 Toxicities Associated with Inappropriate Administration YCANTH is for topical use only. YCANTH is not for oral, mucosal, or ophthalmic use. Life threatening or fatal toxicities can occur if YCANTH is administered orally [see Overdosage (10) ]. Adverse reactions to oral ingestion of cantharidin have included renal failure, blistering and severe damage to the gastrointestinal tract, coagulopathy, seizures, and flaccid paralysis. Advise patients and/or caregivers to avoid oral contact and to avoid touching lesions after YCANTH treatment and to seek medical attention immediately if YCANTH is accidently ingested. Ocular toxicity can occur if YCANTH comes in contact with the eyes.

The following adverse reactions are described elsewhere in the labeling: Local Skin Reactions [see Warnings and Precautions (5.2) ] Most common (incidence ≥1%) adverse reactions are the following local skin reactions at the application site: vesiculation, pain, pruritus, scabbing, erythema, discoloration, application site dryness, edema, and erosion. ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Verrica Pharmaceuticals Inc. at 1-877-837-7422 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch. Local skin reactions are expected and should be reported if they are severe. 6.1 Clinical Trials Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice. YCANTH was studied in two randomized, double-blind, placebo-controlled phase 3 trials, Trial 1 (NCT03377790) and Trial 2 (NCT03377803) (n = 266, and n = 262, respectively) in subjects with molluscum contagiosum. Most patients received a single 24-hour dermal administration of YCANTH or vehicle for each lesion every 3 weeks for up to 4 treatments. YCANTH Solution or vehicle were removed prior to the 24-hour timepoint in 109/311 (35%) subjects treated with YCANTH Solution and 46/216 (21%) subjects treated with vehicle due to treatment-emergent adverse events. Table 1 presents the percentage of subjects with selected adverse reactions (incidence ≥ 1%) by the most severe grade reported during Trial 1 and Trial 2.

8.1 Pregnancy Risk Summary There are no available data with use of YCANTH in pregnant women to evaluate for a drug-associated risk of major birth defects, miscarriage or adverse maternal or fetal outcomes. Animal reproduction studies were not conducted with cantharidin. Given that systemic exposure to cantharidin following topical administration is low, maternal use is not expected to result in fetal exposure to the drug [see Clinical Pharmacology (12.3) ]. The background risk of major birth defects and miscarriage for the indicated population is unknown. All pregnancies have a background risk of birth defect, loss, or other adverse outcomes. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2% to 4% and 15% to 20%, respectively. 8.2 Lactation Risk Summary Avoid application of YCANTH topical solution to areas with increased risk for potential ingestion by or ocular exposure to the breastfeeding child. There are no data on the presence of cantharidin in either human or animal milk, or the effects on the breastfed infant or on milk production. Breastfeeding is not expected to result in exposure of the child to the drug due to the low systemic absorption of YCANTH following topical administration [see Clinical Pharmacology (12.3) ].

Metabolism

Pharmacokinetics of cantharidin were assessed in 16 subjects aged 2 years and older with at least 21 molluscum contagiosum lesions at baseline. Subjects were administered a single, dermal application of cantharidin solution to each lesion.

Oral ingestion of cantharidin has resulted in renal failure, blistering and severe damage to the gastrointestinal tract, coagulopathy, seizures, and flaccid paralysis. In the event that YCANTH topical solution is ingested, patients should seek medical attention immediately and contact a Poison Control Center (1-800-222-1222) or a medical toxicologist for additional overdosage management recommendations.

• Jul 21, 2023NDANDA212905Verrica Pharms

1. 1Application Site Vesicles6443%
2. 2Application Site Pain4429%
3. 3Blister2819%
4. 4Pain149.3%
5. 5Accidental Exposure To Product64.0%
6. 6Application Site Burn64.0%
7. 7Application Site Erythema53.3%
8. 8Blister Rupture53.3%
9. 9Drug Ineffective53.3%
10. 10Application Site Pruritus42.7%
11. 11Application Site Reaction42.7%
12. 12Blood Blister42.7%
13. 13Hypersensitivity42.7%
14. 14Skin Exfoliation42.7%
15. 15Wrong Technique In Product Usage Process42.7%

Recent PubMed references pinned to Cantharidin as a MeSH major topic. Citations link to pubmed.ncbi.nlm.nih.gov.

• Dual-ligand-modified cantharidin nanoparticles for the treatment of hepatocellular carcinoma via the inhibition of Ephb4.
  Drug delivery · 2026 · Jiang W, Zheng H, Wang S, et al.
  PMID 42249613DOI 10.1080/10717544.2026.2682976
• Cancer cell membrane and iRGD peptide co-modified cantharidin liposomes for targeted therapy and immunotherapy of triple-negative breast cancer.
  Free radical biology & medicine · 2026 · Guo Q, Wang S, Zhong Z, et al.
  PMID 41812835DOI 10.1016/j.freeradbiomed.2026.03.026
• Cantharidic acid causes mitochondrial dysfunction via the Nrf2/HO-1/GPX4 pathway to inhibit colorectal cancer progression.
  Histology and histopathology · 2026 · Wei Y, Dai S, Zhang D, et al.
  PMID 41589402DOI 10.14670/HH-25-040
• Integrative analyses of network pharmacology and bioinformatics reveal the synergistic antitumor effects of cantharidin and ginsenosides Rg3 on hepatocellular carcinoma.
  Biochemical pharmacology · 2026 · Gou X, Zhou Z, Wang Y, et al.
  PMID 41520736DOI 10.1016/j.bcp.2026.117700
• [Expert Consensus on the Clinical Application of Sodium Cantharidinate and Vitamin B6 Injection].
  Zhongguo fei ai za zhi = Chinese journal of lung cancer · 2025 · Lung Cancer Specialty Committee of Chinese Elderly Health Care Association
  PMID 41500777DOI 10.3779/j.issn.1009-3419.2025.102.37
• The Putative Involvement of Bacterial Symbionts in Cantharidin Biogenesis: An Explorative Study in Meloidae Insects.
  Microbial ecology · 2025 · Basile A, Spagoni L, Visaggio D, et al.
  PMID 41432792DOI 10.1007/s00248-025-02683-1
• Cantharidin Suppresses Cell Viability and Induces Apoptosis of SK-N-SH and SH-SY5Y Cells.
  In vivo (Athens, Greece) · 2025 · Pei JS, Lee HT, Chen CC, et al.
  PMID 40877180DOI 10.21873/invivo.14064
• Cantharidin-induced enterotoxicity: A molecular insight into intestinal barrier breakdown.
  Journal of ethnopharmacology · 2025 · Liu R, Xiao Y, Shen Q, et al.
  PMID 40850659DOI 10.1016/j.jep.2025.120468

The 10 most recently updated of 24 ClinicalTrials.gov registrations naming Cantharidin as an intervention. Registration is not evidence of efficacy or safety — reference crosswalk only.

• Cantharidin Application in Patients With Common Warts (Verruca Vulgaris) (COVE-3)
  Not yet recruiting · Phase 3 · Interventional · 300 enrolled · Verrica Pharmaceuticals Inc.
  NCT07637734updated 2026-06-10
• Influence of NEP Inhibition on Vascular Leak and Inflammation (NEPi-INFLAMMATION)
  Active not recruiting · Interventional · 48 enrolled · Queen Mary University of London
  NCT05600062updated 2026-05-06
• Long-Term Follow-up Study of Cantharidin (YCANTH [VP-102/TO-208]) in Patients With Common Warts (Verruca Vulgaris)
  Recruiting · Phase 3 · Interventional · 600 enrolled · Verrica Pharmaceuticals Inc.
  NCT07457918updated 2026-05-05
• Cantharidin Application in Patients With Common Warts (Verruca Vulgaris) (COVE-2)
  Recruiting · Phase 3 · Interventional · 300 enrolled · Verrica Pharmaceuticals Inc.
  NCT07246590updated 2026-01-21
• Investigation of the Distinct Mechanisms Involved in Inflammatory Resolution Between Healthy Men and Women
  Recruiting · Early phase 1 · Interventional · 34 enrolled · Queen Mary University of London
  NCT05597098updated 2026-01-07
• Cantharidin and Occlusion in Verruca Epithelium
  Completed · Phase 2 · Interventional · 56 enrolled · Verrica Pharmaceuticals Inc.
  NCT03487549updated 2024-11-27
• A Placebo-Controlled Study Using VP-102 in the Treatment of External Genital Warts
  Completed · Phase 2 · Interventional · 105 enrolled · Verrica Pharmaceuticals Inc.
  NCT03981822updated 2024-11-27
• Cold Atmospheric Plasma Device for Pediatric Molluscum and Verruca
  Completed · Phase 4 · Interventional · 17 enrolled · Medical University of South Carolina
  NCT05070754updated 2024-04-05
• Cantharidin Application in Molluscum Patients-1
  Completed · Phase 3 · Interventional · 266 enrolled · Verrica Pharmaceuticals Inc.
  NCT03377790updated 2022-01-11
• Cantharidin Application in Molluscum Patients
  Completed · Phase 3 · Interventional · 262 enrolled · Verrica Pharmaceuticals Inc.
  NCT03377803updated 2021-12-14

Frequently asked questions

How does Cantharidin work?

The mechanism of action of cantharidin in the treatment of molluscum contagiosum is unknown.

What is Cantharidin used for?

According to FDA labeling, Cantharidin carries indications including: YCANTH is indicated for the topical treatment of molluscum contagiosum in adult and pediatric patients 2 years of age and older. YCANTH is indicated for the topical treatment of molluscum contagiosum in adult and pediatric patients 2 years of age and older.. This is a reference summary of labeled uses, not medical advice or a treatment recommendation.

What class of drug is Cantharidin?

Cantharidin is classified as Enzyme Inhibitors, Decreased Mitosis.

What are the brand names for Cantharidin?

Cantharidin is marketed under brand names including Ycanth.

What are the contraindications for Cantharidin?

Cantharidin labeling lists contraindications including: None None. Always consult the full prescribing information and a clinician.