Velasof 400/100 mg: Sofosbuvir and Velpatasvir Uses, Treatment, and Safety
Written by Dr. Adam Makis in TheSkyMeds Editorial Standards
Medically reviewed by Jonathan Reed, Medical Content Reviewer Aug 31 2026
Velasof 400/100 mg is a prescription antiviral medicine containing 400 mg of sofosbuvir and 100 mg of velpatasvir in one tablet, marketed in India by Hetero Healthcare for chronic hepatitis C. Hetero states that Velasof received Indian regulatory approval in 2017 as a generic version of the sofosbuvir/velpatasvir combination. Sofosbuvir and velpatasvir are direct-acting antivirals (DAAs) that block different steps the hepatitis C virus needs to reproduce, and the combination works across hepatitis C virus (HCV) genotypes 1 through 6. For many treatment-naive adults without cirrhosis, current HCV guidance recommends the 400/100 mg combination for 12 weeks, but treatment can differ when there is advanced liver disease, previous treatment failure, or certain resistance patterns. The medicine can cure hepatitis C in most appropriately selected patients, but cure must be confirmed with an HCV RNA blood test after treatment. Important safety issues include hepatitis B reactivation, serious interactions with amiodarone, and reduced velpatasvir absorption with some acid-reducing medicines. This guide explains how Velasof works, who may receive it, typical treatment approaches, monitoring, interactions, and side effects.
What Is Velasof 400/100 mg Used For?
Velasof combines two antiviral medicines—sofosbuvir 400 mg and velpatasvir 100 mg—in a fixed-dose tablet used for chronic hepatitis C infection.
Hetero announced in 2017 that the Drugs Controller General of India had approved its generic sofosbuvir/velpatasvir combination for India under the Velasof brand. The company also stated that the product was manufactured under a non-exclusive licensing arrangement with Gilead Sciences.
The Hetero information on Velasof approval in India identifies the product as the 400 mg/100 mg sofosbuvir and velpatasvir combination marketed by Hetero Healthcare.
What does sofosbuvir do?
Sofosbuvir is an HCV NS5B polymerase inhibitor.
After activation inside the body, it interferes with an enzyme the hepatitis C virus uses to copy its genetic material. In practical terms, this helps stop production of new viral RNA.
What does velpatasvir do?
Velpatasvir inhibits the HCV NS5A protein.
NS5A is involved in viral replication and assembly. Combining velpatasvir with sofosbuvir attacks HCV at two different stages, which helps explain why the regimen is active against all six major HCV genotypes.
The combination is therefore described as pangenotypic, meaning it can be used across genotypes 1, 2, 3, 4, 5, and 6 when clinically appropriate.
Does Velasof treat hepatitis B or HIV?
No. Sofosbuvir/velpatasvir specifically treats hepatitis C.
A person can have HCV together with hepatitis B or HIV, but those infections require their own management. In fact, hepatitis B status is particularly important because treating HCV with direct-acting antivirals can allow previously controlled HBV to reactivate.
How Is Velasof 400/100 mg Used for Hepatitis C Treatment?
For many adults with chronic hepatitis C, the established sofosbuvir/velpatasvir regimen is one 400 mg/100 mg tablet once daily for 12 weeks. However, that should be understood as a standard regimen for specific patient groups—not as a universal instruction for everyone with hepatitis C.
The exact treatment plan depends on liver status, previous HCV treatment, genotype in selected situations, other medications, and whether decompensated cirrhosis is present.
What is the standard treatment for adults without cirrhosis?
Current AASLD-IDSA simplified treatment guidance lists sofosbuvir 400 mg/velpatasvir 100 mg for 12 weeks as a recommended regimen for eligible treatment-naive adults without cirrhosis.
Before treatment, recommended assessment includes HCV viral load, liver blood tests, kidney function, HIV testing, and hepatitis B screening.
The current AASLD-IDSA simplified hepatitis C treatment guidance also emphasizes reviewing drug interactions and confirming whether cirrhosis is present before treatment begins.
What if someone has compensated cirrhosis?
Compensated cirrhosis means the liver has significant scarring but can still perform its essential functions without major complications such as ascites, severe confusion, or uncontrolled variceal bleeding.
Sofosbuvir/velpatasvir remains an important treatment option in compensated cirrhosis. Current HCV guidance lists 12 weeks for multiple genotypes.
Genotype 3 requires additional attention in simplified treatment because baseline NS5A resistance testing may affect whether sofosbuvir/velpatasvir alone is appropriate.
What if the liver disease is decompensated?
Decompensated cirrhosis is a more advanced condition and should be managed by clinicians experienced in advanced liver disease.
Current AASLD-IDSA guidance recommends sofosbuvir/velpatasvir plus ribavirin for 12 weeks for eligible patients with genotype 1–6 decompensated cirrhosis. For people unable to take ribavirin, 24 weeks of sofosbuvir/velpatasvir is recommended.
Ribavirin has substantial additional safety considerations and should never be added without specialist supervision.
General sofosbuvir/velpatasvir treatment approaches for adults with chronic hepatitis C
Clinical situation | General guideline approach | Important context |
Treatment-naive, no cirrhosis | Sofosbuvir 400 mg/velpatasvir 100 mg for 12 weeks | Pretreatment assessment and drug-interaction review required |
Compensated cirrhosis | Often 12 weeks | Genotype 3 may require resistance assessment |
Decompensated cirrhosis, ribavirin eligible | Sofosbuvir/velpatasvir plus ribavirin for 12 weeks | Specialist management required |
Decompensated cirrhosis, ribavirin ineligible | Sofosbuvir/velpatasvir for 24 weeks | Specialist management required |
Previous DAA treatment failure | May require a different rescue regimen | Do not simply repeat Velasof without specialist advice |
This table summarizes guideline approaches and is not a personalized prescription.
How Should Sofosbuvir and Velpatasvir Be Taken?
The established adult formulation containing sofosbuvir 400 mg and velpatasvir 100 mg is taken orally once daily and may be taken with or without food.
Take the medicine consistently and follow the prescription exactly. Missing doses or stopping treatment early can reduce the chance of eliminating HCV and may complicate future treatment.
Does it need to be taken at the same time every day?
A consistent daily routine helps prevent missed doses.
The most important goal is to take every prescribed dose throughout the complete treatment course. Do not double the next dose or independently extend therapy after a missed dose; follow the instructions supplied by the prescriber or pharmacist.
Can you stop when you feel better?
No. Chronic hepatitis C can cause few or no noticeable symptoms even when the virus remains in the body.
Feeling better does not show that HCV has been eradicated. Treatment should be completed for the prescribed duration, and cure should later be confirmed with laboratory testing.
How is hepatitis C cure confirmed?
A cure is usually assessed by measuring HCV RNA after treatment.
Current HCV guidance emphasizes testing for HCV RNA following completion of direct-acting antiviral therapy. A sustained virologic response 12 weeks after therapy—commonly called SVR12—means the virus remains undetectable and is considered virologic cure.
Finishing 12 weeks of tablets is not by itself proof that hepatitis C has been cured. A follow-up HCV RNA test is needed to confirm sustained virologic response, and people with cirrhosis can still require ongoing liver-cancer surveillance even after HCV has been cured.
What Tests Are Needed Before and During Velasof Treatment?
Hepatitis C treatment is simpler than it was in the interferon era, but appropriate pretreatment evaluation remains essential.
Current HCV guidance recommends reviewing liver status, medications, HCV viral load, hepatitis B status, HIV status, kidney function, and other relevant laboratory results before beginning treatment.
Why is hepatitis B testing essential?
Sofosbuvir/velpatasvir carries an important warning regarding hepatitis B reactivation.
People who currently have or previously had HBV infection can experience reactivation during or after HCV treatment. In severe cases, this has caused hepatitis, liver failure, and death.
The current sofosbuvir/velpatasvir prescribing information instructs healthcare professionals to test for evidence of current or prior HBV infection before starting therapy.
This generally includes hepatitis B surface antigen and hepatitis B core antibody testing, with additional assessment when results indicate current or previous infection.
Is HCV genotype testing always necessary?
Not always.
Because sofosbuvir/velpatasvir is pangenotypic, simplified treatment can sometimes proceed without pretreatment genotype testing in eligible patients. A large minimal-monitoring study cited by AASLD-IDSA achieved a 95% sustained virologic response with 12 weeks of sofosbuvir/velpatasvir using no pretreatment genotyping.
However, genotype can still matter in selected situations, including genotype 3 with compensated cirrhosis, prior treatment failure, and more complex liver disease.
What about kidney disease?
Current U.S. prescribing information states that no sofosbuvir/velpatasvir dose adjustment is recommended for any degree of renal impairment, including end-stage renal disease requiring dialysis.
That does not eliminate the need for kidney assessment, particularly if ribavirin or other medicines are being considered.
Which Medicines Can Interact With Velasof 400/100 mg?
Drug interactions are one of the most important practical safety issues with sofosbuvir/velpatasvir.
Some medicines can lower velpatasvir or sofosbuvir concentrations and make antiviral treatment less effective, while others can develop increased concentrations and produce toxicity.
Why are antacids and acid-reducing medicines important?
Velpatasvir dissolves less effectively as stomach pH rises.
Medicines that reduce stomach acidity can therefore lower velpatasvir exposure. Current prescribing information recommends separating ordinary aluminum- or magnesium-containing antacids from sofosbuvir/velpatasvir by four hours.
H2 blockers such as famotidine have specific timing and dose limits.
Proton-pump inhibitors such as omeprazole are more complicated. Routine coadministration is not recommended; when medically necessary, the prescribing information provides specific timing and food instructions.
Do not independently stop a prescribed acid-suppressing medicine—ask the prescriber or pharmacist to adjust the schedule safely.
Why is amiodarone a major concern?
Combining a sofosbuvir-containing regimen with amiodarone can cause serious symptomatic bradycardia, meaning an abnormally slow heart rate.
Current labeling does not recommend this combination. The risk can be particularly important in people also taking beta blockers or those with advanced liver or underlying heart disease.
If the combination cannot be avoided, specialist cardiac monitoring may be required.
What other medicines need review?
Before treatment, tell the prescriber about every prescription medicine, OTC medicine, vitamin, herbal remedy, and supplement.
Important interaction concerns include certain:
anticonvulsants;
tuberculosis medicines such as rifampin;
HIV medicines;
digoxin;
acid-suppressing medicines; and
herbal products such as St. John's wort.
Strong enzyme or transporter inducers can substantially lower antiviral drug exposure and should not simply be combined with Velasof without specialist review.
Important medication issues with sofosbuvir/velpatasvir
Medicine or product | Why it matters | General safety approach |
Amiodarone | Can cause serious symptomatic bradycardia with sofosbuvir-containing therapy | Combination generally not recommended |
Antacids | Can reduce velpatasvir absorption | Separate according to prescribing instructions |
H2 blockers | Can affect velpatasvir exposure | Dose and timing limits apply |
Proton-pump inhibitors | Can substantially reduce velpatasvir absorption | Routine combination not recommended; specific instructions if unavoidable |
Rifampin and other strong inducers | Can lower antiviral concentrations | Avoid inappropriate combinations |
Certain anticonvulsants | May lower antiviral exposure | Full medication review required |
Some statins | Statin levels may increase | Dose adjustment or monitoring may be needed |
Digoxin | Digoxin exposure may increase | Therapeutic monitoring may be needed |
St. John's wort | Can lower antiviral concentrations | Generally avoid |
What Side Effects and Safety Problems Can Occur?
Most people tolerate sofosbuvir/velpatasvir reasonably well, but side effects can occur.
In clinical studies of the approved combination, headache and fatigue were among the most common adverse reactions.
Individual experience varies, and symptoms developing during treatment are not always caused by the antiviral medicine itself.
What mild side effects might occur?
Reported effects can include:
headache;
tiredness;
nausea;
weakness; and
sleep-related or general constitutional symptoms in some patients.
Do not stop treatment because of a mild side effect without first contacting the treating healthcare professional. Interrupting antiviral therapy unnecessarily can jeopardize the treatment course.
What symptoms require urgent attention?
Seek prompt medical care for severe weakness, fainting, marked dizziness, unusually slow heartbeat, worsening jaundice, severe swelling, confusion, difficulty breathing, or another significant new symptom.
Someone taking amiodarone who develops fainting, near-fainting, dizziness, weakness, chest discomfort, confusion, shortness of breath, or an unusually slow heartbeat requires urgent assessment because of the bradycardia risk.
Safety: Who Needs Specialist Assessment Before Velasof?
Velasof should be used within a structured hepatitis C treatment plan rather than purchased and started solely from an HCV-positive test result.
A positive HCV antibody test alone does not establish active chronic infection. Quantitative HCV RNA testing is required to confirm whether virus is currently present.
People with decompensated cirrhosis, previous DAA treatment failure, liver transplantation, hepatitis B coinfection, complicated HIV therapy, pregnancy considerations, significant medication interactions, or uncertain liver status require more individualized management.
Seek urgent medical care if liver disease is associated with vomiting blood, black stools, increasing abdominal swelling, profound sleepiness or confusion, severe jaundice, or other signs of decompensation.
Completing antiviral treatment also does not erase all future liver risk. People who had cirrhosis before cure generally need continued specialist follow-up, including
Conclusion
Velasof 400/100 mg combines sofosbuvir and velpatasvir, two direct-acting antivirals used to treat chronic hepatitis C across HCV genotypes 1–6. For many treatment-naive adults without cirrhosis, 12 weeks of the 400/100 mg combination is an established guideline regimen, while advanced cirrhosis, genotype 3 in certain settings, or previous treatment failure can change the plan.
Successful treatment requires more than taking the tablets: HBV screening, medication-interaction review, assessment of liver disease, adherence, and an HCV RNA test after therapy are important. If Velasof has been prescribed, review all medicines—including antacids and herbal products—with the treating clinician or pharmacist and complete the prescribed course exactly as directed.
Frequently Asked Questions
1. What is Velasof 400/100 mg used for?
Velasof is used for chronic hepatitis C and contains sofosbuvir 400 mg plus velpatasvir 100 mg. The combination is active against HCV genotypes 1 through 6. Treatment suitability depends on liver status, previous therapy, other medicines, and additional clinical factors.
2. How long is Velasof treatment usually taken?
For many eligible treatment-naive adults without cirrhosis, sofosbuvir/velpatasvir is used for 12 weeks. Treatment can differ in advanced liver disease or previous treatment failure. Decompensated cirrhosis may require ribavirin or a longer regimen under specialist supervision.
3. Can Velasof cure hepatitis C?
Sofosbuvir/velpatasvir can achieve virologic cure in most appropriately selected and adherent patients. Cure is not determined by symptoms; it is confirmed when HCV RNA remains undetectable after treatment, commonly assessed 12 weeks after therapy ends.
4. Can Velasof be taken with food?
Yes. The standard sofosbuvir 400 mg/velpatasvir 100 mg tablet can be taken with or without food. Consistent daily dosing is important. Some interacting medicines, particularly proton-pump inhibitors, can create special food and timing requirements that should be handled professionally.
5. Can I take antacids or omeprazole with Velasof?
Acid-reducing medicines can decrease velpatasvir absorption. Ordinary antacids require separation, while proton-pump inhibitors such as omeprazole are generally not recommended unless medically necessary under specific administration instructions. Ask a pharmacist or prescriber before combining these medicines.
6. What is the most important warning with Velasof?
Hepatitis B reactivation is an important warning, so patients should be tested for current or previous HBV infection before HCV therapy. Serious bradycardia can also occur when sofosbuvir-containing treatment is combined with amiodarone. Both issues require appropriate medical oversight.
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