Sofosbuvir

May be taken with or without food.

Pregnancy (when used in combination with ribavirin or ribavirin-containing regimen). Concomitant use with strong P-gp inducers (e.g. rifampicin, carbamazepine, phenobarbital, phenytoin, St. John's wort).

HBV and HCV co-infected patients. Patients with decompensated hepatic cirrhosis; awaiting liver transplantation. Liver transplant recipients. Patients with diabetes may experience improved glucose control during treatment, which may lead to symptomatic hypoglycaemia (particularly in the 1st 3 months of treatment) if antidiabetic agents are continued at the same dose. Patients who have received or are concurrently receiving amiodarone; concomitantly on vitamin K antagonists. Not recommended as monotherapy and must be given in combination with other agents; if other agents used in combination with sofosbuvir are discontinued, sofosbuvir must also be discontinued. Children. Lactation.

Blood and lymphatic system disorders: Anaemia, neutropenia.
Eye disorders: Blurred vision.
Gastrointestinal disorders: Nausea, vomiting, diarrhoea, abdominal discomfort, constipation, dyspepsia, dry mouth, GERD.
General disorders and administration site conditions: Fatigue, asthenia, irritability, chills, flu-like illness, pain, pyrexia, chest pain.
Investigations: Decreased Hb, lymphocyte and platelet count; decreased weight; increased blood bilirubin.
Metabolism and nutrition disorders: Decreased appetite.
Musculoskeletal and connective tissue disorders: Arthralgia, myalgia, back pain, muscle spasms.
Nervous system disorders: Headache, dizziness, disturbance in attention, migraine, memory impairment.
Psychiatric disorders: Insomnia, depression, anxiety, agitation.
Respiratory, thoracic and mediastinal disorders: Nasopharyngitis, dyspnoea or exertional dyspnoea, cough.
Skin and subcutaneous tissue disorders: Rash, pruritus, alopecia, dry skin.
Potentially Fatal: HBV reactivation (particularly in patients co-infected with HBV and HCV).

PO: B, X (if used w/ ribavirin/peginterferon-α)

This drug may cause dizziness, tiredness, impaired concentration, and blurred vision, if affected, do not drive or operate machinery. When used in combination with ribavirin or ribavirin-containing regimen: Women of childbearing potential and men with female partners of childbearing potential must use an effective birth control method during treatment and for a period of time after treatment (refer to ribavirin detailed product guidelines).

Screen patients for evidence of current or prior HBV (HBsAg, HBV surface antibody and HBV core antibody) before initiating treatment. Obtain baseline quantitative HCV RNA; HCV genotype and subtype (if non-pan-genotypic direct-acting antiviral will be given); CBC, INR, hepatic function, and calculated GFR (within 6 months before starting treatment). Monitor CBC, serum creatinine, calculated GFR and hepatic function during treatment as clinically indicated. Monitor quantitative HCV viral load testing at ≥12 weeks after treatment completion. In patients with serologic evidence of HBV infection: Assess for clinical and laboratory signs of hepatitis flare or HBV reaction during therapy and post-treatment follow-up. In patients receiving concomitant vitamin K antagonists: Closely monitor INR during and post-treatment. In patients who have received or are concurrently receiving amiodarone: Inpatient setting of cardiac monitoring for the 1st 48 hours of concomitant use, then daily outpatient or self-monitoring of heart rate for at least the 1st 2 weeks of treatment. In diabetic patients: Closely monitor blood glucose levels, particularly within the 1st 3 months and assess for signs or symptoms of hypoglycaemia.

Significantly reduced plasma concentration with strong P-gp inducers (e.g. rifampicin, carbamazepine, phenobarbital, phenytoin), which may result in loss of efficacy. May reduce plasma concentration with moderate P-gp inducers (e.g. oxcarbazepine, rifapentine, modafinil). May increase plasma concentration with inhibitors of P-gp and/or BCRP. May affect the efficacy of vitamin K antagonists due to changes in liver function during treatment.
Potentially Fatal: Concomitant use of sofosbuvir-containing regimens with amiodarone may result in severe bradycardia and heart block.

Significantly reduced plasma concentration with St. John's wort.

Description:
Mechanism of Action: Sofosbuvir, a direct-acting nucleotide analogue inhibitor, is a prodrug that undergoes intracellular metabolism to form the pharmacologically active GS-461203 that is incorporated into the hepatitis C virus (HCV) RNA and acts as a chain terminator. It inhibits HCV nonstructural 5B (NS5B) RNA-dependent RNA polymerase, which is necessary for viral replication.
Pharmacokinetics:
Absorption: Rapidly absorbed. Time to peak plasma concentration: Approx 0.5-2 hours.
Distribution: Plasma protein binding: Approx 61-65%.
Metabolism: Extensively metabolised in the liver via phosphorylation into the active nucleoside analogue triphosphate GS-461203; dephosphorylation leads to the formation of nucleoside inactive metabolite GS-331007 (predominant metabolite), which cannot be efficiently rephosphorylated.
Excretion: Via urine (approx 80%; 78% as GS-331007, 3.5% as unchanged drug); faeces (approx 14%); expired air (approx 2.5%). Elimination half-life: 0.4 hours.

Source: National Center for Biotechnology Information. PubChem Compound Summary for CID 45375808, Sofosbuvir. https://pubchem.ncbi.nlm.nih.gov/compound/Sofosbuvir. Accessed Mar. 26, 2025.

Store below 30°C.

Antivirals

J05AP08 - sofosbuvir ; Belongs to the class of antivirals for treatment of HCV infections. Used in the treatment of hepatitis C viral infections.

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