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Registry Hub
Peer-Reviewed Evidence
HomeDrug RegistryCompareDURABOLIN vs ZEPATIER
Comparative Pharmacology

DURABOLIN vs ZEPATIER Comparison

Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.

Clinical EssentialsPharmacokineticsSpecial PopulationsSafety & MonitoringPregnancy & LactationClinical Insights
Differential Analysis

DURABOLIN vs ZEPATIER

Head-to-head clinical comparison of therapeutic indices and safety profiles.

View DURABOLIN Monograph View ZEPATIER Monograph
DURABOLIN
Anabolic Androgenic Steroid
Category C
ZEPATIER
Direct-Acting Antiviral (HCV)
Category C

Clinical Essentials

DURABOLIN
ZEPATIER
Mechanism of Action
DURABOLIN

DURABOLIN (nandrolone phenpropionate) is an anabolic steroid that binds to androgen receptors, increasing protein synthesis and nitrogen retention, promoting muscle growth and bone density. It also stimulates erythropoietin production, increasing red blood cell mass.

ZEPATIER

ZEPATIER is a fixed-dose combination of elbasvir, an HCV NS5A inhibitor, and grazoprevir, an HCV NS3/4A protease inhibitor. Elbasvir inhibits HCV NS5A, disrupting viral replication and assembly. Grazoprevir inhibits the HCV NS3/4A serine protease, preventing cleavage of the HCV polyprotein into mature viral proteins.

Indications
DURABOLIN

Adjunctive therapy to promote weight gain after severe illness, surgery, or trauma,Osteoporosis (off-label),Anemia of renal failure (off-label),HIV/AIDS wasting syndrome (off-label)

ZEPATIER

Treatment of chronic hepatitis C virus (HCV) genotype 1 or 4 infection in adults,Treatment of chronic HCV genotype 1 or 4 infection in pediatric patients 12 years of age and older or weighing at least 30 kg

Standard Dosing
DURABOLIN

100-200 mg intramuscularly every 1-2 weeks for testosterone replacement; for wasting syndromes, 50-100 mg intramuscularly weekly.

ZEPATIER

One tablet (elbasvir 50 mg/grazoprevir 100 mg) orally once daily.

Direct Interaction
DURABOLIN
No Direct Interaction
ZEPATIER
No Direct Interaction

Pharmacokinetics

DURABOLIN
ZEPATIER
Half-Life
DURABOLIN

Terminal elimination half-life: 4-6 days (intramuscular depot), reflecting slow release from injection site and enterohepatic recirculation; clinical steady-state achieved after 3-6 weeks.

ZEPATIER

Elbasvir: terminal half-life approximately 24 hours. Grazoprevir: terminal half-life approximately 31 hours. The prolonged half-lives support once-daily dosing and allow for sustained viral suppression.

Metabolism
DURABOLIN

Special Populations

DURABOLIN
ZEPATIER
Renal Adjustments
DURABOLIN

No specific guidelines; use caution in severe impairment (Cr Cl <30 m L/min) due to fluid retention and potential edema.

ZEPATIER

No dose adjustment required for any degree of renal impairment including end-stage renal disease on dialysis.

Hepatic Adjustments
DURABOLIN

Child-Pugh A: no adjustment; Child-Pugh B: reduce dose by 50%; Child-Pugh C: avoid use due to risk of cholestasis and hepatotoxicity.

Safety & Monitoring

DURABOLIN
ZEPATIER
Black Box Warnings
DURABOLIN
FDA Black Box Warning

Anabolic steroids may cause peliosis hepatis, liver cell tumors, and blood lipid changes associated with increased cardiovascular risk. Prolonged use can lead to azoospermia, oligospermia, and impotence. Not approved for enhancing athletic performance.

Pregnancy & Lactation

DURABOLIN
ZEPATIER
Teratogenic Risk
DURABOLIN

DURABOLIN (nandrolone) is contraindicated in pregnancy. Androgens can cause virilization of the female fetus. First trimester exposure risks clitoromegaly, labial fusion, and urogenital sinus abnormalities. Second and third trimester exposure may lead to clitoromegaly and advanced bone age. Fetal growth restriction and preterm birth are also reported.

ZEPATIER

ZEPATIER (grazoprevir/elbasvir) is contraindicated in pregnancy due to the ribavirin component in some regimens. Ribavirin is teratogenic in all trimesters, causing fetal malformations and embryolethality. Grazoprevir/elbasvir alone has no adequate human data, but animal studies show no teratogenicity. However, combination with ribavirin mandates avoidance in pregnancy.

Clinical Insights

DURABOLIN
ZEPATIER
Clinical Pearls
DURABOLIN

Durabolin (nandrolone phenylpropionate) is an injectable anabolic steroid with a shorter ester than nandrolone decanoate, allowing for faster onset and offset. Monitor liver function tests and lipid profiles, as it can cause HDL suppression and LDL elevation. Use with caution in patients with pre-existing cardiac, hepatic, or renal disease. Suppresses endogenous testosterone; consider testosterone replacement during and after therapy. Detectable on doping tests for up to 18 months in athletes; educate accordingly.

ZEPATIER

ZEPATIER (elbasvir/grazoprevir) is indicated for chronic HCV genotypes 1 or 4. Prior to initiation, test for NS5A resistance-associated substitutions (RASs) in genotype 1a. In patients with genotype 1a and baseline NS5A RASs, treatment duration is 16 weeks with ribavirin. Avoid in moderate to severe hepatic impairment (Child-Pugh B or C). Monitor hepatic function closely. Coadministration with strong CYP3A4 inducers (e.g., rifampin, carbamazepine) is contraindicated. Also contraindicated with OATP1B1/3 inhibitors (e.g., cyclosporine) and certain HIV protease inhibitors (e.g., atazanavir, darunavir, lopinavir). Grazoprevir increases serum creatinine due to OATP2B1 inhibition, but this does not reflect true renal function decline.

Safety Verification

Known Interactions

DURABOLIN Risks

No interactions on record

ZEPATIER Risks

No interactions on record

Clinical Q&A

Frequently Asked Questions

1. What is the primary difference between DURABOLIN and ZEPATIER?

DURABOLIN and ZEPATIER are distinct pharmacological agents. DURABOLIN belongs to the Anabolic Androgenic Steroid class and is primarily used for Adjunctive therapy to promote weight gain after severe illness, surgery, or traumaOsteoporosis (off-label)Anemia of renal failure (off-label)HIV/AIDS wasting syndrome (off-label). ZEPATIER belongs to the Direct-Acting Antiviral (HCV) class and is primarily used for Treatment of chronic hepatitis C virus (HCV) genotype 1 or 4 infection in adultsTreatment of chronic HCV genotype 1 or 4 infection in pediatric patients 12 years of age and older or weighing at least 30 kg. Their specific mechanisms of action, pharmacokinetic characteristics, and side effects differ.

2. Are DURABOLIN and ZEPATIER safe during pregnancy?

The maternal-fetal safety profiles of these drugs differ. DURABOLIN carries a safety status of Category C, whereas ZEPATIER safety is classified as Category C. Consult a board-certified physician or healthcare specialist to establish an accurate, individualized pregnancy risk assessment before starting either therapy.

Hepatic metabolism via reduction and conjugation; primarily excreted in urine as metabolites (e.g., 19-norandrosterone and 19-noretiocholanolone).

ZEPATIER

Elbasvir is metabolized primarily by CYP3A. Grazoprevir is metabolized primarily by CYP3A. Mild oxidation and glucuronidation are minor pathways.

Excretion
DURABOLIN

Primarily renal: 90% as metabolites (glucuronide and sulfate conjugates), 10% unchanged; negligible biliary/fecal elimination.

ZEPATIER

Elbasvir: primarily biliary/fecal (≥90% as metabolites, <1% unchanged in urine). Grazoprevir: primarily biliary/fecal (≥90% as metabolites, <1% unchanged in urine). Renal elimination is negligible for both.

Protein Binding
DURABOLIN

85-95% bound to sex hormone-binding globulin (SHBG) and albumin; high affinity for SHBG, reducing free active fraction.

ZEPATIER

Elbasvir: ≥99.9% bound, primarily to albumin and α1-acid glycoprotein. Grazoprevir: 98.8% bound, primarily to albumin and α1-acid glycoprotein.

VD (L/kg)
DURABOLIN

4-6 L/kg, indicating extensive tissue distribution, particularly to skeletal muscle, bone, and prostate.

ZEPATIER

Elbasvir: apparent Vd approximately 4.5 L/kg (high, indicating extensive tissue distribution). Grazoprevir: apparent Vd approximately 19 L/kg (very high, likely due to binding to plasma proteins and tissue uptake).

Bioavailability
DURABOLIN

Intramuscular: ~100% (depot formulation); oral: negligible (<1% due to first-pass hepatic metabolism).

ZEPATIER

Elbasvir: absolute bioavailability not determined in humans; oral absorption is high. Grazoprevir: absolute bioavailability approximately 27% after oral administration; absorption is enhanced with food (high-fat meal increases AUC by 1.5-fold).

ZEPATIER

Contraindicated in moderate (Child-Pugh B) or severe (Child-Pugh C) hepatic impairment. No dose adjustment required in mild (Child-Pugh A) hepatic impairment.

Pediatric Dosing
DURABOLIN

Not recommended in children due to premature epiphyseal closure and potential virilization; limited data, use only under expert supervision for delayed growth.

ZEPATIER

Not approved for use in pediatric patients; safety and efficacy not established.

Geriatric Dosing
DURABOLIN

Initiate at lowest effective dose (e.g., 50 mg IM every 2 weeks) due to increased risk of prostatic hypertrophy, fluid retention, and polycythemia.

ZEPATIER

No dose adjustment required; however, clinical studies indicate similar safety and efficacy as in younger adults, but caution is warranted due to potential age-related comorbidities.

ZEPATIER
FDA Black Box Warning

Risk of hepatitis B virus (HBV) reactivation in patients coinfected with HCV and HBV, which may result in fulminant hepatitis, hepatic failure, and death. Test all patients for evidence of current or prior HBV infection before initiating treatment.

Warnings/Precautions
DURABOLIN

Risk of hepatic dysfunction, peliosis hepatis, hepatocellular carcinoma, hyperlipidemia, cardiovascular disease, edema, hypertension, glucose intolerance, premature closure of epiphyseal growth plates in children, virilization in women, and prostate hypertrophy in men. Monitor liver function, lipid profile, and hematocrit. Use with caution in patients with cardiac, renal, or hepatic disease.

ZEPATIER
  • Risk of hepatitis B virus reactivation
  • Hepatic decompensation with use in patients with moderate or severe hepatic impairment (Child-Pugh B or C)
  • Elevation of total bilirubin and/or ALT levels
  • Risk of adverse reactions due to drug interactions (e.g., strong CYP3A inducers/inhibitors)
Contraindications
DURABOLIN

Known hypersensitivity to nandrolone or any component, pregnant or breastfeeding women, men with carcinoma of the breast or prostate, nephrotic syndrome, hypercalcemia, severe hepatic dysfunction, and patients with a history of myocardial infarction or coronary artery disease.

ZEPATIER
  • Moderate or severe hepatic impairment (Child-Pugh B or C)
  • Use with strong CYP3A inducers (e.g., rifampin, St. John's wort, carbamazepine, phenytoin)
  • Use with certain HIV medications (e.g., efavirenz, etravirine, nevirapine, atazanavir/ritonavir, lopinavir/ritonavir, darunavir/ritonavir, tipranavir/ritonavir)
  • Use with cyclosporine
Adverse Reactions
DURABOLIN
Data Pending
ZEPATIER
Data Pending
Food Interactions
DURABOLIN

No specific food interactions reported. However, maintain a balanced diet low in saturated fats and sodium to mitigate adverse lipid and cardiovascular effects. Avoid excessive alcohol consumption due to hepatotoxicity risk.

ZEPATIER

ZEPATIER can be taken with or without food. No specific food restrictions are required. Grapefruit and grapefruit juice may increase exposure to grazoprevir; although not contraindicated, consider avoiding large quantities.

Lactation Summary
DURABOLIN

Nandrolone is excreted into breast milk. The milk-to-plasma ratio is not established. Androgens may suppress lactation and cause virilization in the nursing infant. Use during breastfeeding is contraindicated.

ZEPATIER

No data on human milk excretion. M/P ratio unknown. Ribavirin accumulates in breast milk and is contraindicated during breastfeeding. Grazoprevir/elbasvir: animal studies show excretion in milk; potential for adverse effects. Avoid breastfeeding during treatment and for 7 days after last dose.

Pregnancy Dosing
DURABOLIN

No dosing adjustments are applicable as DURABOLIN is contraindicated in pregnancy. No pharmacokinetic data in pregnancy to guide dose modification.

ZEPATIER

No dose adjustment studies in pregnancy. ZEPATIER is not recommended during pregnancy due to ribavirin component. If inadvertently used, no specific dose adjustment; consult maternal-fetal specialist.

Maternal Safety Status
DURABOLIN
Category C
ZEPATIER
Category C
Patient Counseling
DURABOLIN

This medication is for intramuscular injection only; do not inject intravenously.,Report signs of liver problems (jaundice, dark urine, abdominal pain) or heart issues (chest pain, shortness of breath) immediately.,May cause changes in libido, acne, hair growth, or voice deepening; these may be irreversible.,Regular blood tests are required to monitor liver function, cholesterol, and blood count.,Do not share needles; proper disposal of used syringes is mandatory.,Avoid use during pregnancy and breastfeeding.,May interact with blood thinners (e.g., warfarin) and oral antidiabetics; advise dose adjustments.

ZEPATIER

Take ZEPATIER exactly as prescribed, one tablet once daily with or without food.,Do not stop or skip doses without consulting your healthcare provider.,Inform your doctor of all medications you take, including over-the-counter drugs and herbal supplements, to avoid serious interactions.,Notify your healthcare provider immediately if you experience symptoms of liver problems: yellowing of skin or eyes, dark urine, pale stools, nausea, vomiting, or right upper abdominal pain.,ZEPATIER may elevate creatinine levels without reflecting kidney damage; your doctor will monitor appropriately.,If you have genotype 1a HCV, your doctor will test for specific resistance mutations to determine the correct treatment duration.,Avoid alcohol during treatment as it can exacerbate liver injury.,Use effective contraception during treatment and for 2 weeks after the last dose if you or your partner can become pregnant.