Reviewed on 5/19/2022

What Is Dactinomycin and How Does It Work?

Dactinomycin is a prescription medication used to treat the symptoms of Wilms Tumor, Rhabdomyosarcoma, Ewing Sarcoma, Gestational Trophoblastic Neoplasms, Testicular Cancer, and Locoregional Malignancies.

  • Dactinomycin is available under the following different brand names: Cosmegen

What Are Dosages of Dactinomycin?

Adult and pediatric dosage

Injection, of powder for reconstitution

  • 500mcg/vial

Wilms Tumor

Adult and pediatric dosage

  • 45 mcg/kg IV every 3-6 weeks for up to 26 weeks  


Adult and pediatric dosage

  • 15 mg/kg IV on Days 1-5 every 3-9 weeks for up to 112 weeks  

Ewing Sarcoma

Adult and pediatric dosage

  • 1250 mcg/m² IV every 3 weeks for 51 weeks  

Gestational Trophoblastic Neoplasms

Adult and pediatric dosage

  • Nonmetastatic and low-risk metastatic disease: 12 mcg/kg IV once a day for 5 days as a single agent  
  • High-risk metastatic disease: 500 mcg IV on Days 1 and 2 every 2 weeks for up to 8 weeks  

Testicular Cancer

Adult and pediatric dosage

  • 1000 mcg/m² IV once every 3 weeks for 12 weeks as part of a cisplatin-based, multi-agent combination regimen  

Locoregional Solid Malignancies

Adult dosage

  • Pelvis/lower extremity: 50 mcg/kg IV once in combination with melphalan  
  • Upper extremity: 35 mcg/kg IV once in combination with melphalan

Dosage Considerations – Should be Given as Follows: 

  • See “Dosages”

What Are Side Effects Associated with Using Dactinomycin?

Common side effects of Dactinomycin include:

  • hair loss,
  • fever,
  • infections,
  • low blood cell counts,
  • rash,
  • trouble swallowing,
  • nausea,
  • vomiting, and
  • tiredness

Serious side effects of Dactinomycin include:

  • hives,
  • difficulty breathing,
  • swelling of the face, lips, tongue, or throat,
  • fever,
  • sore throat,
  • burning eyes,
  • skin pain,
  • red or purple skin rash with blistering and peeling,
  • swelling or tenderness in the stomach (upper right side),
  • rapid weight gain,
  • swelling in the arms or legs,
  • dark urine,
  • yellowing of the skin or eyes (jaundice),
  • redness of the skin or the inside of the mouth and throat,
  • sores or white patches in or around the mouth,
  • trouble swallowing or talking,
  • dry mouth,
  • bad breath,
  • altered sense of taste,
  • blisters,
  • ulcers,
  • skin changes at the injection site,
  • chills,
  • tiredness,
  • mouth sores,
  • skin sores,
  • easy bruising,
  • unusual bleeding,
  • pale skin,
  • cold hands and feet,
  • light-headedness, and
  • shortness of breath  
  • Rare side effects of Dactinomycin include:
  • none 

This is not a complete list of side effects and other serious side effects or health problems that may occur as a result of the use of this drug. Call your doctor for medical advice about serious side effects or adverse reactions. You may report side effects or health problems to FDA at 1-800-FDA-1088.

What Other Drugs Interact with Dactinomycin?

If your medical doctor is using this medicine to treat your pain, your doctor or pharmacist may already be aware of any possible drug interactions and may be monitoring you for them. Do not start, stop, or change the dosage of any medicine before checking with your doctor, health care provider, or pharmacist first

This information does not contain all possible interactions or adverse effects. Visit the RxList Drug Interaction Checker for any drug interactions. Therefore, before using this product, tell your doctor or pharmacist about all the products you use. Keep a list of all your medications with you and share this information with your doctor and pharmacist. Check with your health care professional or doctor for additional medical advice or concerns if you have health questions.

What Are Warnings and Precautions for Dactinomycin?


  • None

Effects of drug abuse

  • None

Short-Term Effects

  • See “What Are Side Effects Associated with Using Dactinomycin?”

Long-Term Effects

  • See “What Are Side Effects Associated with Using Dactinomycin?”


  • Increased risk of secondary malignancy or leukemia following treatment
  • Severe and fatal Veno-occlusive disease reported; risk increased with young age (i.e., below 4 years) or concomitant radiotherapy; monitor for increased AST, ALT, total bilirubin, hepatomegaly, weight gain, or ascites; consider delaying the next dose; resume, reduce the dose, or permanently discontinue based on the severity of reaction and disease being treated
  • If extravasation occurs, immediately interrupt the injection or infusion and apply ice (see Administration)
  • Severe and fatal myelosuppression reported; monitor blood cell counts before each cycle; delay next dose if severe myelosuppression has not improved; consider dose reduction for patients with prolonged myelosuppression based on the severity of reaction and disease being treated
  • Severe mucocutaneous reactions (e.g., Steven-Johnson syndrome, toxic epidermal necrolysis) can occur; permanently discontinue
  • Renal toxicity reported; monitor creatinine and electrolytes frequently
  • Hepatotoxicity reported; monitor transaminases, alkaline phosphatase, and bilirubin before and during treatment
  • Reduce dose by 50% during concomitant radiation; use caution when administering within 2 months of radiation
  • Can cause fetal harm; inform patients of the potential risk to a fetus and use effective contraception (see Pregnancy)
  • Drug interaction overview
    • Vaccination with live viral vaccines is not recommended before or during treatment; not studied
    • Published in vitro studies report that dactinomycin may be a P-glycoprotein and OATP1B3 substrate

Pregnancy & Lactation

  • Based on findings from animal studies and its mechanism of action, can cause fetal harm when administered to pregnant women
  • In animal reproduction studies, administration to pregnant animals during the period of organogenesis was teratogenic, resulting in malformations at doses lower than the recommended human dose
  • Verify the pregnancy status of females of reproductive potential before initiating
  • Contraception
    • Females of reproductive: Use effective contraception during treatment and for at least 6 months after the final dose
    • Males with female partners of reproductive potential: Use effective contraception during treatment and for 3 months after the final dose
  • Lactation
    • There are no data on the presence of dactinomycin or its metabolites in human milk or their effects on the breastfed infant or milk production

Health Solutions From Our Sponsors