Sofomax400 mg

Sofomax 400 mg is a direct-acting antiviral medicine used, always in combination with other hepatitis C medicines, for the treatment of chronic hepatitis C virus (HCV) infection in adults, with the specific combination regimen and duration depending on the HCV genotype, prior treatment history, and presence or absence of cirrhosis. It is also used in combination regimens for HCV/HIV-1 co-infected patients, and, in some protocols, for patients with hepatocellular carcinoma awaiting liver transplantation, to prevent post-transplant HCV recurrence.

Sofomax 400 mg is never used alone; it is always combined with another direct-acting antiviral (such as velpatasvir, ledipasvir, or daclatasvir) or with ribavirin (with or without peginterferon alfa), and the exact regimen is determined by a specialist based on HCV genotype and clinical factors.

Contains Sofomax 400 mg as the active ingredient, available as oral film-coated tablets, commonly in a 400 mg strength, either alone or as part of a fixed-dose combination tablet with another direct-acting antiviral (such as Sofomax 400 mg/velpatasvir or Sofomax 400 mg/ledipasvir).

Sofomax 400 mg is an oral antiviral medicine that directly targets the machinery hepatitis C virus uses to copy its genetic material, helping clear the infection when combined with other antiviral medicines as part of a specialist-directed treatment regimen. It represented a major advance in hepatitis C treatment, offering high cure rates with all-oral regimens, replacing older interferon-based treatments in most cases. Because it is always used in combination, and because it carries a serious, specific interaction with the heart medicine amiodarone, treatment must be planned and monitored by a specialist familiar with hepatitis C management.

Therapeutic Class: Antiviral (Direct-Acting Antiviral for Hepatitis C)

Sofomax 400 mg is a prodrug that, once inside liver cells, is converted to its active triphosphate form, which is then incorporated into new viral RNA by the hepatitis C virus's own NS5B polymerase, causing chain termination and halting viral replication. It is a substrate of the drug transporters P-glycoprotein and BCRP; its predominant circulating metabolite (GS-331007) is renally eliminated, which is why dosing has not been established in patients with severe renal impairment (exposure to this metabolite can be increased several-fold in this population).

• Taken orally, once daily, with or without food
• Take at approximately the same time each day for consistent blood levels
• Take exactly as prescribed alongside the partner medicine(s) in your regimen; do not change your dose or schedule without your doctor's advice
• If a dose is missed and it is within 18 hours of the usual time, take it as soon as possible; if more than 18 hours have passed, skip the missed dose and resume the normal schedule the next day, without doubling up

The following interactions require careful assessment:

• Amiodarone - critical interaction: co-administration with Sofomax 400 mg-containing regimens has resulted in serious, sometimes fatal, symptomatic bradycardia, including cases requiring pacemaker insertion, occurring up to 2 weeks after starting hepatitis C treatment; this combination is not recommended, and if unavoidable, requires inpatient cardiac monitoring for the first 48 hours followed by ongoing outpatient monitoring, particularly in patients also on beta-blockers or with underlying cardiac disease.
• P-glycoprotein inducers (such as rifampicin and St. John's Wort): can significantly reduce Sofomax 400 mg blood levels, reducing its antiviral effect; concurrent use is not recommended.
• Strong CYP inducers (such as carbamazepine and phenytoin): may reduce blood levels of Sofomax 400 mg and its combination partner drugs, reducing effectiveness.
• Diabetes medicines: clearing hepatitis C infection can alter liver function and has been associated with changes in blood glucose control, including reports of significant hypoglycemia in diabetic patients; blood glucose should be monitored closely, particularly in the first weeks of treatment.

Common side effects (of Sofomax 400 mg-based regimens generally)

• Fatigue
• Headache
• Nausea
• Insomnia
• Additional side effects depend heavily on the specific combination partner drug (such as ribavirin's anaemia, or peginterferon's flu-like symptoms) used alongside Sofomax 400 mg

Serious side effects (seek urgent medical attention)

• Serious symptomatic bradycardia when combined with amiodarone: chest pain, confusion, severe dizziness, fainting, memory problems, shortness of breath, unusual tiredness - seek emergency care immediately, as this can be fatal.
• Hepatitis B reactivation: in patients with current or prior hepatitis B infection, HBV reactivation has been reported during or after HCV direct-acting antiviral treatment, in some cases leading to serious liver problems; testing for HBV before starting treatment and monitoring during and after treatment is required.
• Significant, symptomatic hypoglycemia has been reported in some diabetic patients as hepatitis C is cleared; monitor blood glucose closely.
• Signs of a severe allergic reaction: rash, swelling, difficulty breathing.

Pregnancy

Data on Sofomax 400 mg alone in human pregnancy are limited. When Sofomax 400 mg is used as part of a ribavirin-containing regimen, that combination is contraindicated in pregnancy, given ribavirin's significant teratogenic risk, and effective contraception is required for the patient and their partner during and for a defined period after treatment with a ribavirin-containing regimen.

Breastfeeding

It is not known whether Sofomax 400 mg passes into human milk; use during breastfeeding should be discussed with the treating specialist, particularly if the regimen includes ribavirin, which is also present in breast milk.

• Never combine with amiodarone unless there is genuinely no alternative and the treating specialist arranges close cardiac monitoring, given the risk of serious, potentially fatal bradycardia.
• Test for hepatitis B before starting treatment - HBV reactivation is a recognized risk with HCV direct-acting antivirals in patients with current or past HBV infection; monitor during and after HCV treatment.
• Sofomax 400 mg is never used as monotherapy - it must always be combined with another appropriate hepatitis C medicine as directed by a specialist; using it alone will not adequately treat the infection and increases the risk of antiviral resistance.
• Monitor blood glucose closely in diabetic patients during treatment, given reports of significant hypoglycemia as liver function improves with viral clearance.
• If the regimen includes ribavirin, effective contraception is essential given ribavirin's teratogenic risk; do not become pregnant during treatment or for the period specified after completing a ribavirin-containing regimen.

Limited clinical data exist on Sofomax 400 mg overdose; doses well above the recommended amount have not been associated with acute toxicity in limited studies, but a substantial reduction in the peak drug concentration through supportive measures may be considered. Suspected significant overdose, or symptoms suggesting cardiac effects (particularly if amiodarone is also involved), should be evaluated promptly by a healthcare professional; treatment is generally supportive, including cardiac monitoring where relevant, provided by the treating specialist team.

Store at controlled room temperature (generally 15-30°C), in the original container, protected from moisture.

• Severe renal impairment (eGFR below 30 mL/min/1.73m²) or end-stage renal disease: No specific dose recommendation can be given, since Sofomax 400 mg's predominant circulating metabolite accumulates substantially in this population; use requires specialist assessment.
• Hepatic impairment: No dose adjustment is generally required for mild to moderate impairment; use in decompensated cirrhosis follows specific specialist protocols, often incorporating ribavirin.
• HIV co-infection: Sofomax 400 mg-based regimens are used in HCV/HIV-1 co-infected patients, with attention to interactions between the HCV and HIV medication regimens.

Treatment duration depends on the specific regimen, HCV genotype, prior treatment history, and presence of cirrhosis, typically ranging from 12 to 24 weeks, as determined by the treating specialist. The full prescribed course must be completed for the best chance of viral cure (sustained virologic response); stopping early risks treatment failure and antiviral resistance.

Drug Class: Nucleotide analogue NS5B polymerase inhibitor

Sofomax 400 mg works by mimicking one of the natural building blocks the hepatitis C virus uses to copy its RNA genome. Once incorporated into the growing viral RNA chain by the virus's own polymerase enzyme, Sofomax 400 mg's structure prevents the chain from being extended further, effectively halting viral replication. This mechanism is shared by nucleotide analogues generally and offers activity across multiple HCV genotypes.

Sofomax 400 mg-based regimens are used in pediatric patients with chronic hepatitis C in some age groups and specific combination products, under specialist pediatric hepatology or infectious disease supervision, with dosing and combination partner drug selection following the specific product's approved pediatric labeling.