Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
GONAL-F RFF REDI-JECT vs DANAZOL
Clinician-reviewed, head-to-head comparison of mechanism, dosing, pharmacokinetics, and safety profiles.
Last clinically reviewed: July 2026 · OpiCalc Medical Review Team
GONAL-F (follitropin alfa) is a recombinant human follicle-stimulating hormone (FSH) that binds to FSH receptors on ovarian follicles, stimulating follicular growth, maturation, and estrogen production.
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.
Ovulation induction in anovulatory women,Controlled ovarian hyperstimulation for assisted reproductive technologies (ART),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. Initial dose 75-225 IU once daily for 7-14 days, titrated based on ovarian response. Maximum daily dose 450 IU.
300-600 mg orally twice daily; maximum 800 mg/day
Terminal elimination half-life: approximately 24 hours; clinically, steady-state is achieved within 3-5 days of daily dosing.
Terminal elimination half-life is 4-4.5 hours; clinical context: requires multiple daily dosing to maintain therapeutic levels.
Primarily metabolized in the liver via peptide hydrolysis, with renal excretion of metabolites.
Primarily hepatic: undergoes oxidation and conjugation via CYP3A4, with metabolites excreted in urine and feces.
Renal: approximately 70-80% of the dose; fecal: <20%
Primarily hepatic metabolism; approximately 60% excreted in feces, 30% in urine as metabolites.
Approximately 30-40% bound to plasma proteins, primarily albumin.
Highly protein bound: 97-99%, primarily to albumin.
Approximately 8-10 L/kg, indicating extensive distribution into extracellular fluid.
Approximately 1.5 L/kg; indicates extensive distribution into tissues, exceeding total body water.
Subcutaneous: approximately 70-80%.
Oral bioavailability is approximately 100% due to extensive absorption, but first-pass metabolism reduces systemic availability to about 70-80%.
No dose adjustment required for mild to moderate renal impairment. Not studied in severe renal impairment (Cr Cl <30 m L/min) or dialysis; use with caution.
No adjustment required for GFR ≥10 m L/min; avoid use in GFR <10 m L/min due to fluid retention risk
No dose adjustment required for mild to moderate hepatic impairment (Child-Pugh A or B). Not studied in severe hepatic impairment (Child-Pugh C); use with caution.
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 effectiveness not established.
2-5 mg/kg/dose orally twice daily; maximum 400 mg/day
Not indicated for use in geriatric patients. Safety and effectiveness not established.
Start at low end of adult dose, titrate cautiously due to increased risk of fluid retention and thromboembolism
GONAL-F should only be used by physicians thoroughly familiar with infertility problems and their management. Use may lead to ovarian hyperstimulation syndrome (OHSS) and multiple gestations.
Danazol may cause thrombotic events, including pulmonary embolism and thrombophlebitis. It is contraindicated in patients with a history of thrombosis.
Ovarian Hyperstimulation Syndrome (OHSS): risk of severe OHSS with pulmonary and vascular complications,Ovarian torsion and rupture,Multiple gestation and birth defects,Thromboembolic events,Ectopic pregnancy,Ovarian neoplasms,Respiratory distress syndrome in offspring
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 follitropin alfa or any excipient,High levels of FSH indicating primary ovarian failure,Uncontrolled thyroid or adrenal dysfunction,Sex hormone-dependent tumors (e.g., ovarian, breast, uterine),Pregnancy,Ovarian cyst or enlargement of unknown origin
Pregnancy, lactation, porphyria, severe hepatic/renal/cardiac disease, undiagnosed abnormal genital bleeding, history of thromboembolic disorders, androgen-dependent tumors.
No known food interactions. No dietary restrictions required. However, grapefruit juice may increase estrogen levels and should be avoided during treatment. Maintain adequate hydration.
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.
FDA Pregnancy Category X. Contraindicated in pregnancy. No fetal risk data in first trimester due to lack of exposure; however, follicular stimulation may induce ovarian hyperstimulation syndrome and multiple gestations. Second and third trimester: no indicated use; potential for harm based on animal studies.
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.
Not recommended during breastfeeding. Excretion in human milk unknown; M/P ratio not determined. May suppress lactation due to hormonal effects.
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.
No dose adjustment; drug is contraindicated in pregnancy and should be discontinued if pregnancy occurs. No pharmacokinetic changes studied in pregnancy due to contraindication.
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 REDI-JECT contains recombinant human follicle-stimulating hormone (follitropin alfa). It is used for ovulation induction and controlled ovarian hyperstimulation. Administer subcutaneously, rotating injection sites. Monitor ovarian response via ultrasound and estradiol levels to avoid ovarian hyperstimulation syndrome (OHSS). Dose adjustments based on patient response; individualize therapy. Can be used in combination with Gn RH agonists or antagonists.
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.
Rotate injection sites (abdomen, thigh, upper arm) to reduce lipodystrophy.,Do not shake the Redi-Ject device; store in refrigerator (2-8°C) before first use, then at room temperature for up to 28 days.,Report severe pelvic pain, nausea, or rapid weight gain (possible OHSS).,Avoid alcohol and grapefruit juice as they may affect hormone levels.
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 REDI-JECT vs DANAZOL, answered by our medical review team.
GONAL-F RFF REDI-JECT is a Gonadotropin that works by GONAL-F (follitropin alfa) is a recombinant human follicle-stimulating hormone (FSH) that binds to FSH receptors on ovarian follicles, stimulating follicular growth, maturation, and estrogen production.. 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 REDI-JECT 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 REDI-JECT is: Subcutaneous injection. Initial dose 75-225 IU once daily for 7-14 days, titrated based on ovarian response. Maximum daily dose 450 IU.. 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 REDI-JECT 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 REDI-JECT is classified as Category C. FDA Pregnancy Category X. Contraindicated in pregnancy. No fetal risk data in first trimester due to lack of exposure; however, follicular stimulation may induce ovarian hyperstimu. 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.