Sofosbuvir
A nucleotide NS5B polymerase inhibitor for chronic hepatitis C, always combined with other antivirals, as in sofosbuvir-daclatasvir.
Drug card
- How it works
- Ending hepatitis C RNA chains by blocking the viral NS5B polymerase
- Used for
- Chronic hepatitis C, with other antivirals
- Known for
- Severe slow heart rate with amiodarone
- Hepatitis B reactivation
- Its name
- -vir means an antiviral; -buvir means a hepatitis C NS5B polymerase inhibitor
Study it as a flashcard, and it comes back before you forget it.
Mechanism of action
How does sofosbuvir work?
A nucleotide prodrug converted inside cells to a uridine analog triphosphate, which the hepatitis C NS5B RNA polymerase builds into viral RNA, ending the chain. It does not inhibit human DNA or RNA polymerases or mitochondrial RNA polymerase. It is active against several genotypes and is never given alone.
Uses
What is sofosbuvir used for?
- Chronic hepatitis C, with other antivirals
Side effects
Side effects of sofosbuvir
- Severe slow heart rate with amiodaroneKnown forSerious
- Hepatitis B reactivationKnown forSerious
- Tiredness
- Headache
- Nausea
- Trouble sleeping
- Anemia, when combined with ribavirin
- Decreased appetite in children
- Low blood sugar in diabetes as the virus clearsSerious
Known for marks what an exam expects you to know it for.
Watch for
Cautions and what sets it apart
- Test for hepatitis B first, and watch for a flare during and after treatment.
- Amiodarone is not advised: serious bradycardia and a fatal cardiac arrest have occurred.
- Avoid intestinal P-gp inducers such as rifampicin and St John's wort, which lower its levels.
- Watch INR on warfarin and blood sugar in diabetes, as liver function changes when the virus clears.
Good to know: WHO notes that direct-acting antivirals cure over 95% of people treated, and that sofosbuvir with daclatasvir is the most widely used low-cost regimen for all genotypes.
Remember it
A way to remember it
A false U for the viral copier.
Sofosbuvir becomes a uridine look-alike that the hepatitis C polymerase NS5B builds into new viral RNA, and the copy stops there.
Written for biofideX
Its name
-vir means antiviral
Sub-stems name the target: -ciclovir, -amivir, -fovir, -tegravir, -navir, -buvir, -virine (NNRTIs). Lamivudine and zidovudine are antivirals without it.
-buvir means hepatitis C NS5B polymerase inhibitor
Sofosbuvir, a nucleotide prodrug, blocks NS5B, the hepatitis C RNA polymerase. HCV NS5A inhibitors end in -asvir and HCV protease inhibitors in -previr.
- Every drug name stem
Its class
NS5B polymerase inhibitors
NS5B is the RNA-dependent RNA polymerase that copies the hepatitis C virus genome. Sofosbuvir, a nucleotide prodrug, is converted inside cells to a uridine analog triphosphate, which NS5B builds into viral RNA, ending the chain. It does not inhibit human DNA or RNA polymerases. These drugs are always combined with other direct-acting antivirals.
Easily mixed up with nucleoside reverse transcriptase inhibitors and antiherpes nucleoside analogues.
Sources
Checked against
Written for biofideX in plain words, after checking these references:
For learning pharmacology, not for treatment decisions: no doses are given, and a prescriber, pharmacist or the product's own label is the word on any one patient. Spotted a mistake? Tell us and we'll correct it.
Antivirals
Sofosbuvir is one of 10 drugs practiced together here: their classes, how they work, what they treat and what they're known for.
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