Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
SOVALDI vs VOSEVI
Clinician-reviewed, head-to-head comparison of mechanism, dosing, pharmacokinetics, and safety profiles.
Last clinically reviewed: July 2026 · OpiCalc Medical Review Team
Sofosbuvir is a nucleotide analog inhibitor of the hepatitis C virus (HCV) NS5B RNA-dependent RNA polymerase, which is essential for viral replication. It is converted to the active triphosphate form (GS-461203) that competes with natural nucleotides and causes chain termination upon incorporation into viral RNA.
VOSEVI (sofosbuvir, velpatasvir, and voxilaprevir) is a fixed-dose combination of a nucleotide analog NS5B polymerase inhibitor (sofosbuvir), an NS5A inhibitor (velpatasvir), and a NS3/4A protease inhibitor (voxilaprevir). The combination inhibits hepatitis C virus replication by targeting multiple viral proteins.
Treatment of chronic hepatitis C virus (HCV) infection as a component of a combination antiviral regimen (FDA approved),Off-label: Treatment of HCV in patients with hepatocellular carcinoma awaiting liver transplantation
Treatment of chronic hepatitis C virus genotype 1-6 infection in adults who have no prior treatment with a NS5A inhibitor and have been previously treated with a regimen containing sofosbuvir without a NS5A inhibitor,Treatment of chronic hepatitis C virus genotype 1-6 infection in adults who have prior treatment with a NS5A inhibitor-containing regimen
400 mg orally once daily with or without food.
One tablet (sofosbuvir 400 mg/velpatasvir 100 mg/voxilaprevir 100 mg) orally once daily with food for 8 weeks.
Terminal half-life of sofosbuvir is approximately 0.4-0.5 hours; the predominant circulating metabolite GS-331007 has a terminal half-life of 27 hours. This long half-life supports once-daily dosing.
Sofosbuvir: 0.5 h (parent), 27 h (GS-331007 metabolite); Velpatasvir: 17 h; Voxilaprevir: 33 h. Terminal half-lives support once-daily dosing; metabolite GS-331007 accumulates but is less active.
Sofosbuvir is a prodrug that undergoes extensive hepatic metabolism to form the active triphosphate. It is metabolized by cathepsin A (Cat A) and carboxylesterase 1 (CES1), followed by phosphorylation by nucleoside kinases. The inactive metabolite GS-331007 is eliminated renally.
Sofosbuvir is metabolized by cathepsin A and CES1 to the active metabolite GS-461203, followed by dephosphorylation. Velpatasvir and voxilaprevir are metabolized by CYP2B6, CYP2C8, CYP3A4 (minor). Voxilaprevir is also a substrate of OATP1B1/1B3.
Primarily fecal (77% of absorbed dose as metabolites, 3.5% as unchanged drug) with minor renal elimination (3.5% total, mainly metabolites). Biliary excretion contributes to fecal elimination.
Sofosbuvir: 80% renal, 14% fecal; Velpatasvir: 94% fecal, 0.4% renal; Voxilaprevir: 40% renal, 47% fecal. VOSEVI components are eliminated primarily via biliary/fecal (velpatasvir, voxilaprevir) and renal (sofosbuvir) pathways.
Sofosbuvir is 61-65% bound to human plasma proteins; the metabolite GS-331007 has minimal protein binding (<1%).
Sofosbuvir: ~85% bound; Velpatasvir: >99.5% bound; Voxilaprevir: >99% bound. Primarily to albumin.
Sofosbuvir: approximately 0.25 L/kg (based on 80 kg individual, Vd ~20 L), suggesting limited extravascular distribution. GS-331007: Vd is not clinically relevant as it is inactive.
Sofosbuvir: ~1.8 L/kg; Velpatasvir: ~4.9 L/kg; Voxilaprevir: ~3.9 L/kg. Large Vd indicates extensive tissue distribution, including liver (target organ).
Oral bioavailability of sofosbuvir is not precisely determined but is adequate for therapeutic effect; absorption is enhanced by food (high-fat meal increases AUC by ~1.8-fold).
Oral: sofosbuvir ~92%, velpatasvir ~29%, voxilaprevir ~44% (fasted). Administer with food to increase absorption (especially voxilaprevir AUC 2- to 4-fold).
No dose adjustment required for mild to moderate renal impairment. For severe renal impairment (e GFR <30 m L/min/1.73 m2) or end-stage renal disease requiring hemodialysis, no prospective data; may use with caution but insufficient data to recommend dose adjustment.
No dose adjustment required for mild to moderate renal impairment (e GFR ≥30 m L/min/1.73 m²). For severe renal impairment (e GFR <30 m L/min/1.73 m²) or end-stage renal disease, safety and efficacy not established; use not recommended.
No dose adjustment required for mild to moderate hepatic impairment (Child-Pugh A or B). Not recommended for use in patients with severe hepatic impairment (Child-Pugh C) due to significantly increased exposure and potential toxicity; contraindicated.
Contraindicated in Child-Pugh class B or C decompensated cirrhosis due to increased voxilaprevir exposure. No dose adjustment required for Child-Pugh class A cirrhosis.
Approved for patients aged 3 years and older: weight <17 kg: 150 mg orally once daily; weight 17 to <35 kg: 200 mg orally once daily; weight ≥35 kg: 400 mg orally once daily; administer with food.
Safety and efficacy in pediatric patients <18 years have not been established; no specific dosing recommendations.
No specific dose adjustment required for elderly patients; dosing based on hepatic and renal function with consideration of age-related decline in renal function. Monitor for adverse events as elderly may have higher risk of comorbidities and concomitant medications.
No dose adjustment required based on age. Clinical studies included patients ≥65 years with no overall differences in safety or efficacy; consider renal function monitoring.
NOT APPROVED BY FDA FOR THE TREATMENT OF HEPATITIS C VIRUS (HCV) INFECTION. WAIT, SOVALDI IS APPROVED. CORRECTION: No black box warning for Sovaldi (sofosbuvir) as a single agent. However, when used in combination with other antivirals, there is a risk of hepatitis B virus (HBV) reactivation. The FDA has issued a boxed warning regarding HBV reactivation for direct-acting antivirals, including sofosbuvir-containing regimens.
Risk of hepatitis B virus reactivation in patients coinfected with HCV and HBV. Test all patients for evidence of current or prior HBV infection before starting treatment. Monitor HCV/HBV coinfected patients for hepatitis B reactivation during treatment and post-treatment follow-up.
Risk of hepatitis B virus reactivation in patients coinfected with HBV and HCV, which can lead to fulminant hepatitis and death.,Symptomatic bradycardia when used with amiodarone, especially in patients also taking beta-blockers or with underlying cardiac comorbidities.,Reduced efficacy in patients with genotype 3 HCV infection when used without ribavirin.,Use with caution in patients with severe renal impairment (e GFR <30 m L/min) or end-stage renal disease due to increased exposure of the metabolite GS-331007.
Risk of HBV reactivation,Risk of bradycardia when coadministered with amiodarone; avoid use unless alternatives are not available,Decompensated hepatic impairment: not recommended for use in patients with moderate or severe hepatic impairment (Child-Pugh B or C),Drug interactions: potential for reduced therapeutic effect if given with P-gp inducers (e.g., rifampin) or moderate/strong CYP inducers
Hypersensitivity to sofosbuvir or any component of the formulation,Coadministration with potent P-glycoprotein (P-gp) inducers (e.g., rifampin, St. John's wort) which may significantly reduce sofosbuvir efficacy
Concomitant use with rifampin (CYP2B6 and P-gp inducer) due to significant decrease in voxilaprevir concentrations,Concomitant use with St. John's wort (Hypericum perforatum) due to decreased drug concentrations,Coadministration with rosuvastatin is contraindicated due to increased risk of myopathy/rhabdomyolysis,Severe hepatic impairment (Child-Pugh C)
No significant food interactions. May be taken with or without food. Grapefruit or other fruit juices have no known clinically relevant interaction with sofosbuvir.
VOSEVI should be taken with food to ensure adequate absorption. A high-fat meal (approximately 800–1000 calories, 50% fat) increases absorption of velpatasvir and voxilaprevir. Avoid concurrent use with St. John's wort, rifampin, and other P-glycoprotein inducers, as they may reduce VOSEVI efficacy.
Sovaldi (sofosbuvir) is classified as FDA Pregnancy Category B. Animal studies have shown no evidence of teratogenicity at exposures up to 10 times the human therapeutic dose. However, human data are limited. In animal reproduction studies, no fetal harm was observed in rats and rabbits at exposures 10 and 5 times the human exposure, respectively. No dose-limiting maternal or fetal toxicity was noted in rats or rabbits. The risk of teratogenicity in humans is considered low, but because of limited human data, use during pregnancy should only be if clearly needed. Ribavirin, which is commonly used in combination with sofosbuvir for chronic hepatitis C, is contraindicated in pregnancy due to its known teratogenic and embryocidal effects (Pregnancy Category X). Therefore, concomitant use of ribavirin imposes significant fetal risk, especially during the first trimester.
VOSEVI is contraindicated in pregnancy due to risk of fetal harm. No adequate human data; animal studies show developmental toxicity at clinically relevant exposures. Use effective contraception during treatment and for 6 months after completion.
It is not known whether sofosbuvir or its metabolites are excreted in human breast milk. In lactating rats, sofosbuvir was detected in milk at concentrations similar to maternal plasma. The M/P ratio in rats was approximately 1.0. The pharmacokinetics in nursing infants have not been evaluated. Because of the potential for adverse reactions in breastfed infants, and because ribavirin (if coadministered) is contraindicated during lactation, breastfeeding is not recommended during treatment with Sovaldi. The CDC recommends that women with chronic HCV can breastfeed, as HCV is not transmitted through breast milk; however, the safety of sofosbuvir during lactation has not been established.
No data on presence in human milk; animal studies indicate excretion. M/P ratio unknown. Risk of adverse effects in infant not excluded; advise against breastfeeding during therapy.
No specific dosing adjustments for sofosbuvir are recommended during pregnancy based on pharmacokinetic changes. In animal studies, pharmacokinetics were not significantly altered in pregnant vs non-pregnant animals. However, physiological changes in pregnancy (e.g., increased plasma volume, altered hepatic metabolism) may affect drug disposition, but no clinical data are available to support dose adjustment. If used with ribavirin, ribavirin dose should be based on body weight (1000 mg/day if <75 kg, 1200 mg/day if ≥75 kg, divided twice daily) and adjusted for hematologic toxicity. For severe renal impairment (e GFR <30 m L/min/1.73 m²), sofosbuvir is not recommended due to increased exposure of its metabolite. In all cases, the combination of sofosbuvir with ribavirin is not recommended during pregnancy due to ribavirin's teratogenicity.
No data on pharmacokinetic changes in pregnancy; dose adjustments not established. VOSEVI is not recommended in pregnancy; if inadvertent exposure occurs, consult specialist.
Sovaldi (sofosbuvir) is a pangenotypic NS5B polymerase inhibitor used in combination with other direct-acting antivirals for chronic hepatitis C. Monitor for bradycardia when coadministered with amiodarone; avoid concurrent use if possible. Renal impairment (e GFR <30 m L/min) is a contraindication due to accumulation of the sofosbuvir metabolite GS-331007. All-oral regimens achieve >95% sustained virologic response. Hepatitis B reactivation risk requires screening and monitoring.
VOSEVI is a fixed-dose combination of sofosbuvir (NS5B inhibitor), velpatasvir (NS5A inhibitor), and voxilaprevir (NS3/4A protease inhibitor) indicated for treatment-naive and treatment-experienced patients with chronic HCV genotype 1–6 without cirrhosis or with compensated cirrhosis. It is particularly useful for patients who have failed prior NS5A inhibitor-containing regimens, including those with genotype 3 and compensated cirrhosis. Monitor for hepatitis B reactivation in HBV co-infected patients. Dose adjustment not required for mild or moderate renal impairment, but safety not established in severe renal impairment or ESRD. Caution with amiodarone due to risk of serious bradycardia. Check for drug interactions with P-gp inducers, CYP2B6, CYP2C8, and CYP3A4 substrates.
Take this medication exactly as prescribed, usually once daily with or without food.,Do not stop taking this medication without consulting your doctor, even if you feel well.,Use effective contraception during treatment and for 30 days after finishing, as ribavirin-containing regimens can cause birth defects.,Report any signs of serious side effects like slow heartbeat (dizziness, fainting) or allergic reactions.,Avoid drinking alcohol as it can worsen liver disease and reduce treatment effectiveness.,Inform your doctor about all medications, including over-the-counter drugs and supplements, to avoid interactions.,You will need regular blood tests to monitor liver function, viral load, and side effects.
Take VOSEVI exactly as prescribed, usually one tablet once daily with food.,Do not skip doses or stop taking VOSEVI without talking to your doctor.,If you have hepatitis B co-infection, your doctor will monitor you for HBV reactivation during and after treatment.,Tell your doctor about all medications, including over-the-counter drugs, herbal supplements, and vitamins, as VOSEVI may interact with them.,Common side effects include headache, fatigue, diarrhea, and nausea. Contact your doctor if you experience severe abdominal pain, jaundice, or signs of liver injury.,VOSEVI does not prevent transmission of HCV. Practice safe sex and avoid sharing needles to reduce the risk of spreading the virus.
No interactions on record
No interactions on record
Explore head-to-head clinical comparisons of other medications in the same therapeutic classes.
Common clinical questions about SOVALDI vs VOSEVI, answered by our medical review team.
SOVALDI is a Direct-acting antiviral that works by Sofosbuvir is a nucleotide analog inhibitor of the hepatitis C virus (HCV) NS5B RNA-dependent RNA polymerase, which is essential for viral replication. It is converted to the active triphosphate form (GS-461203) that competes with natural nucleotides and causes chain termination upon incorporation into viral RNA.. VOSEVI is a Direct-Acting Antiviral Combination that works by VOSEVI (sofosbuvir, velpatasvir, and voxilaprevir) is a fixed-dose combination of a nucleotide analog NS5B polymerase inhibitor (sofosbuvir), an NS5A inhibitor (velpatasvir), and a NS3/4A protease inhibitor (voxilaprevir). The combination inhibits hepatitis C virus replication by targeting multiple viral proteins.. They differ in pharmacokinetic profiles, FDA-approved indications, and side effect profiles.
Potency comparisons between SOVALDI and VOSEVI 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 SOVALDI is: 400 mg orally once daily with or without food.. The standard adult dose of VOSEVI is: One tablet (sofosbuvir 400 mg/velpatasvir 100 mg/voxilaprevir 100 mg) orally once daily with food for 8 weeks.. 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 SOVALDI and VOSEVI 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. SOVALDI is classified as Category C. Sovaldi (sofosbuvir) is classified as FDA Pregnancy Category B. Animal studies have shown no evidence of teratogenicity at exposures up to 10 times the human therapeutic dose. Howe. VOSEVI is classified as Category C. VOSEVI is contraindicated in pregnancy due to risk of fetal harm. No adequate human data; animal studies show developmental toxicity at clinically relevant exposures. Use effective. Always consult a maternal-fetal medicine specialist before taking either drug during pregnancy or lactation.