Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
GONAL-F RFF vs DANAZOL
Clinician-reviewed, head-to-head comparison of mechanism, dosing, pharmacokinetics, and safety profiles.
Last clinically reviewed: July 2026 · OpiCalc Medical Review Team
Recombinant human follicle-stimulating hormone (FSH) that binds to FSH receptors on ovarian granulosa cells and testicular Sertoli cells, stimulating follicular growth and maturation and spermatogenesis.
Danazol is a synthetic androgen derived from ethisterone that suppresses pituitary-ovarian axis by inhibiting gonadotropin release, leading to decreased estrogen and progesterone levels. It also has weak androgenic and progestational activity.
Induction of ovulation in anovulatory women,Controlled ovarian hyperstimulation for assisted reproductive technologies,Spermatogenesis induction in hypogonadotropic hypogonadism (with h CG)
FDA: Treatment of endometriosis, fibrocystic breast disease, hereditary angioedema,Off-label: Idiopathic thrombocytopenic purpura, precocious puberty, gynecomastia
Subcutaneous injection, initially 75-150 IU once daily for 5-7 days for ovulation induction. For controlled ovarian hyperstimulation, 75-300 IU once daily starting day 2 or 3 of cycle. Dose adjusted based on response.
300-600 mg orally twice daily; maximum 800 mg/day
Terminal elimination half-life: approximately 24-30 hours (range 24-36 h) following subcutaneous administration; supports once-daily dosing regimen.
Terminal elimination half-life is 4-4.5 hours; clinical context: requires multiple daily dosing to maintain therapeutic levels.
Primarily hepatic via proteolytic degradation and renal clearance
Primarily hepatic: undergoes oxidation and conjugation via CYP3A4, with metabolites excreted in urine and feces.
Renal excretion: approximately 70% of the dose is eliminated in urine as intact hormone and metabolites; fecal excretion is negligible (<5%).
Primarily hepatic metabolism; approximately 60% excreted in feces, 30% in urine as metabolites.
Approximately 95% bound to plasma proteins, primarily albumin and sex hormone-binding globulin (SHBG).
Highly protein bound: 97-99%, primarily to albumin.
Volume of distribution: 6-10 L/kg, indicating extensive distribution into extracellular fluid and tissues (e.g., ovaries).
Approximately 1.5 L/kg; indicates extensive distribution into tissues, exceeding total body water.
Subcutaneous: approximately 70-80% (relative to intravenous administration); intramuscular: 100% (absolute bioavailability for Gonal-f RFF not explicitly reported, but similar to follitropin alfa).
Oral bioavailability is approximately 100% due to extensive absorption, but first-pass metabolism reduces systemic availability to about 70-80%.
No specific dose adjustment provided by manufacturer. GFR <30 m L/min: use with caution due to limited data.
No adjustment required for GFR ≥10 m L/min; avoid use in GFR <10 m L/min due to fluid retention risk
No specific dose adjustment provided by manufacturer. Child-Pugh Class C: use with caution; no established guidelines.
Child-Pugh A: no adjustment; Child-Pugh B: reduce dose by 50%; Child-Pugh C: contraindicated
Not indicated for use in pediatric patients. Safety and efficacy not established.
2-5 mg/kg/dose orally twice daily; maximum 400 mg/day
Not indicated for use in geriatric patients. Safety and efficacy not established.
Start at low end of adult dose, titrate cautiously due to increased risk of fluid retention and thromboembolism
None
Danazol may cause thrombotic events, including pulmonary embolism and thrombophlebitis. It is contraindicated in patients with a history of thrombosis.
Ovarian hyperstimulation syndrome (OHSS),Ovarian torsion,Multiple pregnancy,Pulmonary embolism and thromboembolic events,Ovarian enlargement,Ectopic pregnancy,Congenital malformations (risk similar to general population)
Hepatotoxicity (monitor LFTs), pseudotumor cerebri (benign intracranial hypertension), androgenic effects (hirsutism, acne, voice deepening), lipid changes (decreased HDL, increased LDL), thromboembolic events, and premature closure of epiphyses in children.
Hypersensitivity to FSH or any excipients,High levels of FSH indicating primary gonadal failure,Uncontrolled non-gonadal endocrinopathies (thyroid, adrenal, pituitary),Sex hormone dependent tumors (ovarian, breast, uterus, testis, hypothalamus, pituitary),Abnormal uterine bleeding of undetermined origin,Pregnancy and lactation
Pregnancy, lactation, porphyria, severe hepatic/renal/cardiac disease, undiagnosed abnormal genital bleeding, history of thromboembolic disorders, androgen-dependent tumors.
No significant food interactions. Maintain a balanced diet; avoid excessive alcohol intake as it may impair fertility. Caffeine in moderation (≤200 mg/day) is generally acceptable, but discuss with your healthcare provider.
Take with food or milk to minimize gastrointestinal irritation. Avoid grapefruit juice as it may alter drug metabolism. Limit alcohol consumption due to increased risk of hepatotoxicity.
Fetal risk cannot be ruled out. Category X: contraindicated in pregnancy due to risk of multiple gestation and ectopic pregnancy; no systematic evidence of teratogenicity but animal studies show post-implantation loss and fetal abnormalities at high doses.
Danazol is contraindicated in pregnancy. First trimester exposure is associated with virilization of female fetus including clitoromegaly, labioscrotal fusion, and urogenital sinus abnormalities. Risk in second and third trimesters is also significant due to androgenic effects; fetal growth restriction and preterm birth may occur. No safe gestational period exists.
No human data; M/P ratio unknown. Excretion in breast milk unknown; caution advised due to potential for serious adverse effects in infant.
Danazol is excreted in human milk; M/P ratio not determined. Potential for adverse effects in breastfed infant (e.g., androgenization). Use is contraindicated during breastfeeding due to risk of virilization and other hormonal effects.
Contraindicated in pregnancy; no dosing adjustments applicable as therapy is discontinued upon confirmed pregnancy.
Danazol is contraindicated in pregnancy; no dose adjustment recommendations exist. If inadvertently used during pregnancy, discontinue immediately and monitor for fetal effects. Pharmacokinetic changes in pregnancy are not studied; dose modifications are not applicable due to contraindication.
GONAL-F RFF (follitropin alfa) is a recombinant follicle-stimulating hormone (FSH) used for ovulation induction and controlled ovarian hyperstimulation. Administer subcutaneously; rotate injection sites to prevent lipodystrophy. Adjust dose based on ovarian response monitoring (ultrasound and estradiol levels). Risk of ovarian hyperstimulation syndrome (OHSS) requires vigilance; withhold h CG if estradiol >3000 pg/m L or >20 follicles ≥14 mm. Use with Gn RH agonist or antagonist to prevent premature LH surge. Prefilled syringe ensures accurate dosing; do not mix with other drugs. Store refrigerated, but may be stored at room temperature (≤25°C) for up to 28 days.
Monitor liver function tests; androgenic effects (acne, hirsutism, voice deepening) may occur; use with caution in patients with cardiac or renal impairment; may potentiate warfarin; effective for hereditary angioedema prophylaxis; check pregnancy test before initiation due to teratogenicity.
Inject exactly as prescribed, preferably at the same time daily.,Rotate injection sites (abdomen, thigh) to avoid lumps or pain.,Do not skip doses; contact your doctor if you miss a dose.,Report symptoms of OHSS: severe pelvic pain, bloating, nausea, rapid weight gain, or decreased urination.,Avoid pregnancy tests until instructed, as the medication may cause false results.,Store unopened vials in the refrigerator. Once opened, use within 28 days if kept at room temperature.
Do not take if pregnant or planning pregnancy; use effective contraception.,Report symptoms of liver toxicity (jaundice, dark urine, abdominal pain) immediately.,Avoid alcohol as it may increase hepatotoxicity risk.,May cause weight gain, acne, or voice changes; report if bothersome.,Take with food to reduce GI upset.,Use sunscreen due to photosensitivity risk.,Do not discontinue abruptly; taper under medical supervision.
No interactions on record
"Formestane, an aromatase inhibitor, reduces estrogen synthesis, while danazol, a synthetic androgen, possesses weak androgenic and anabolic activity. Concomitant use may lead to additive fluid retention due to danazol's mineralocorticoid-like effects and formestane's potential to cause fluid retention through estrogen withdrawal. This can result in peripheral edema, hypertension, or exacerbation of heart failure in susceptible patients."
"Danazol, a synthetic androgen with weak androgenic activity, may reduce the therapeutic efficacy of vildagliptin, a dipeptidyl peptidase-4 (DPP-4) inhibitor used for glycemic control in type 2 diabetes. The proposed mechanism involves danazol-induced activation of cytochrome P450 enzymes (particularly CYP3A4) and potential upregulation of glucagon counter-regulatory pathways, leading to increased vildagliptin clearance and diminished inhibition of DPP-4. Clinically, this interaction may result in elevated postprandial glucose levels and reduced HbA1c reduction, compromising glycemic management."
"Danazol, an androgenic steroid, can induce hepatic microsomal enzymes, particularly CYP2C9, which accelerates the metabolism of glipizide, a sulfonylurea antidiabetic agent. This increased clearance reduces glipizide's plasma concentrations, diminishing its insulinotropic effect and potentially leading to hyperglycemia and loss of glycemic control in patients with type 2 diabetes mellitus."
Explore head-to-head clinical comparisons of other medications in the same therapeutic classes.
Common clinical questions about GONAL-F RFF vs DANAZOL, answered by our medical review team.
GONAL-F RFF is a Gonadotropin that works by Recombinant human follicle-stimulating hormone (FSH) that binds to FSH receptors on ovarian granulosa cells and testicular Sertoli cells, stimulating follicular growth and maturation and spermatogenesis.. DANAZOL is a Androgen/Antigonadotropin that works by Danazol is a synthetic androgen derived from ethisterone that suppresses pituitary-ovarian axis by inhibiting gonadotropin release, leading to decreased estrogen and progesterone levels. It also has weak androgenic and progestational activity.. They differ in pharmacokinetic profiles, FDA-approved indications, and side effect profiles.
Potency comparisons between GONAL-F RFF and DANAZOL depend on the specific clinical indication. These are agents from distinct pharmacological classes and are not directly interchangeable by dose. A physician or clinical pharmacist should guide any therapeutic switching decisions.
The standard adult dose of GONAL-F RFF is: Subcutaneous injection, initially 75-150 IU once daily for 5-7 days for ovulation induction. For controlled ovarian hyperstimulation, 75-300 IU once daily starting day 2 or 3 of cycle. Dose adjusted based on response.. The standard adult dose of DANAZOL is: 300-600 mg orally twice daily; maximum 800 mg/day. Dosing should always be individualized based on indication, renal and hepatic function, age, and other patient factors.
No direct drug-drug interaction has been formally documented between GONAL-F RFF and DANAZOL in current clinical databases. However, individual patient risk factors including other medications, organ function, and comorbidities should always be evaluated by a qualified healthcare provider.
The maternal-fetal safety profiles differ. GONAL-F RFF is classified as Category C. Fetal risk cannot be ruled out. Category X: contraindicated in pregnancy due to risk of multiple gestation and ectopic pregnancy; no systematic evidence of teratogenicity but anima. DANAZOL is classified as Category C. Danazol is contraindicated in pregnancy. First trimester exposure is associated with virilization of female fetus including clitoromegaly, labioscrotal fusion, and urogenital sinus. Always consult a maternal-fetal medicine specialist before taking either drug during pregnancy or lactation.