Danazol and Simvastatin: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Danazol
Simvastatin
How we grade severity & evidence
Severity levels
- Contraindicated: These should generally not be used together.
- Major: Potentially serious — often needs a change or close monitoring.
- Moderate: Can be significant — usually manageable with monitoring.
- Minor: Usually limited clinical impact.
Evidence grades
- Established: Well documented — supported by controlled studies or strong clinical data.
- Probable: Good supporting evidence, though not definitively proven.
- Suspected: Some evidence suggests this interaction, but it is not well established.
- Possible: Limited or conflicting evidence; the interaction may occur.
- Theoretical: Predicted from the drugs' pharmacology; not yet confirmed in people.
Ratings come from the documented interaction literature and are reviewed by a pharmacist. They describe the documented risk of the combination, not what will necessarily happen to you — your dose, timing, and health picture all matter.
What happens
An increased risk of myopathy or rhabdomyolysis
Interaction Deep Dive
Concomitant use of danazol and simvastatin is contraindicated due to increased risk of developing myopathy and rhabdomyolysis1. In a case report, concomitant therapy with simvastatin 40 mg/day and danazol 600 mg/day resulted in fatal rhabdomyolysis in an 80-year-old man receiving danazol for idiopathic thrombocytopenic purpura 3. In another case report, a 68-year-old man on chronic simvastatin 40 mg/day developed rhabdomyolysis and acute renal failure 4 weeks after initiation of danazol 200 mg three times daily for autoimmune hemolytic anemia. Rhabdomyolysis and renal failure resolved after danazol discontinuation and temporary hemodialysis 4. Concomitant use of ezetimibe in combination with simvastatin with danazol is also contraindicated 2.
Why it happens (mechanism)
Unknown
Literature reports
2 reports — tap to read
a) Concomitant administration of simvastatin and danazol resulted in fatal rhabdomyolysis in an 80-year-old man with idiopathic thrombocytopenia purpura (ITP). This patient had been receiving simvastatin 20 mg/day for 2 years when danazol (400 mg then 200 mg per day) was started for treatment of ITP. After 3 months of combination simvastatin and danazol treatment, simvastatin was increased to 40 mg/day and danazol to 600 mg/day. Thirty-five days later, he was seen in the emergency room (ER) following an accidental fall caused by generalized weakness. In the ER, he complained of fatigue, mild pretibial edema, progressive bilateral leg pain, and cramping. Following examination, he was discharged from the ER with diagnoses of collapse and nasal contusion. Two days later, he was admitted to the hospital with oliguria, dark urine, muscle pain and tenderness. Laboratory tests revealed a creatine kinase (CK) of 22,700 units/L (100 times the ULN), a BUN of 42 mmol/L, a serum creatinine of 720 mcmol/L, and an AST and ALT of 442 and 314 unit/L, respectively. Despite medical management, including hemodialysis and drug discontinuation, his CK level rose to 35,000 unit/L. Six days after hospital admission for rhabdomyolysis, he died of acute renal failure. An assessment of causality on the Naranjo adverse drug reaction probability scale rated the association of rhabdomyolysis and concomitant use of danazol and simvastatin as probable. This patient had risk factors for statin-induced adverse events, including older age, renal dysfunction, and a history of type 2 diabetes mellitus 3.
b) A 68-year-old man developed rhabdomyolysis and acute renal failure following concomitant simvastatin and danazol therapy. He received chronic therapy for hyperlipidemia with simvastatin 40 mg/day. Other chronic concomitant medications included allopurinol, atenolol, furosemide, and acetylsalicylic acid, and he initiated danazol 200 mg three times daily for autoimmune hemolytic anemia previously treated with azaTHIOprine and predniSONE. Prior to admission, he had a 2-week history of decreased appetite, increased dyspnea, reduced urine output, and tea-colored urine. Four weeks after starting danazol therapy, he presented with a 5-day history of progressive muscle pain and weakness. He declined using any nonprescription medications and consumption of grapefruit juice. Upon admission, he was unable to lift his arms or stand up, and all medications were withheld. Relevant laboratory findings included a creatine kinase level of 50,060 unit/L, a BUN of 31.1 mmol/L, a serum creatinine of 1230 mcmol/L, a urine myoglobin level of greater than 10,000 mcg/L, and a potassium level of 7.9 mmol/L. He was treated for hyperkalemia and following 8 hemodialysis sessions, his oliguria resolved. Atenolol, acetylsalicylic acid, and prednisone were resumed and he was discharged 4 days later. An assessment of causality on the Naranjo adverse drug reaction probability scale rated the association of rhabdomyolysis and concomitant use of danazol and simvastatin as probable 4.
Common questions
Can I take Danazol and Simvastatin together?
An increased risk of myopathy or rhabdomyolysis Always confirm with your pharmacist or prescriber before making any change.
How serious is the Danazol and Simvastatin interaction?
It is rated contraindicated. These should generally not be used together.
How quickly could this interaction happen?
The documented onset is "unspecified". The timing of this interaction is not well characterized.
How strong is the evidence for this interaction?
The evidence is graded "probable". Good supporting evidence, though not definitively proven.
From our Q&A
Real reader questions about these medications, each personally answered by our pharmacist:
Questions for your pharmacist
- Does my dose of Danazol or Simvastatin need adjusting while I take them together?
- What symptoms should prompt me to call you or my prescriber right away?
- Does the timing of my doses matter for this combination?
- Is there a safer alternative to one of these medications for me?
References (4)
- Product Information: ZOCOR(R) oral tablets, simvastatin oral tablets. Organon & Co (per FDA), Jersey City, NJ, 2022. DailyMed
- Product Information: VYTORIN(R) oral tablets, ezetimibe simvastatin oral tablets. Organon LLC (per FDA), Jersey City, NJ, 2024. DailyMed
- Stankovic I, Vlahovic-Stipac A, Putnikovic B, et al: Concomitant administration of simvastatin and danazol associated with fatal rhabdomyolysis. Clin Ther 2010; 32(5):909-914. PubMed
- Andreou ER & Ledger S: Potential drug interaction between simvastatin and danazol causing rhabdomyolysis. Can J Clin Pharmacol 2003; 10(4):172-174.
Keep reading about Danazol
Keep reading about Simvastatin
These medications also interact with supplements
Prescription drugs aren't the whole picture — herbal and dietary supplements can interact with them too. From the evidence-graded Natural Medicines database:
major · moderate · minor — check everything you take with our drug–supplement interaction checker.
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