Drug interactions
Nafcillin + Sofosbuvir-velpatasvir
Severity: Major
Nafcillin and Sofosbuvir-velpatasvir: major interaction.
Last updated
For healthcare professionals — reference only. This page is a brief summary, not medical advice and not a substitute for official labeling or clinical judgement. Always verify before prescribing or dispensing.
Summary
Nafcillin is a CYP3A4 inducer and is expected to lower, not raise, velpatasvir levels. Reduced exposure could weaken HCV treatment response.
What this interaction means in plain words
Nafcillin and Sofosbuvir-velpatasvir can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for.
Why it happens
Nafcillin induces CYP3A4 (and possibly P-gp), increasing clearance of velpatasvir and sofosbuvir.
What to do
Avoid if possible; use an alternative antibiotic for the infection or delay HCV therapy. If it must be used, monitor HCV RNA.
What to ask your pharmacist
- Does the benefit of taking both outweigh the risk in my case?
- Do I need any blood test, ECG or other check while on both?
- What early warning signs should I watch for, and what should I do if they appear?
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Other interactions of Sofosbuvir-velpatasvir
- Rifampin + Sofosbuvir-velpatasvir Contraindicated
- Rifapentine + Sofosbuvir-velpatasvir Contraindicated
- Sofosbuvir-velpatasvir + St john's wort Contraindicated
- Amiodarone + Sofosbuvir-velpatasvir Major
- Apalutamide + Sofosbuvir-velpatasvir Major
- Carbamazepine + Sofosbuvir-velpatasvir Major
Frequently asked questions
Can I take Nafcillin with Sofosbuvir-velpatasvir?
MediHelp rates the interaction as major. Nafcillin and Sofosbuvir-velpatasvir can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for. Nafcillin is a CYP3A4 inducer and is expected to lower, not raise, velpatasvir levels. Reduced exposure could weaken HCV treatment response.
How serious is the interaction between Nafcillin and Sofosbuvir-velpatasvir?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid if possible; use an alternative antibiotic for the infection or delay HCV therapy. If it must be used, monitor HCV RNA.
What other medicines interact with Sofosbuvir-velpatasvir?
MediHelp also lists interactions of Sofosbuvir-velpatasvir with, for example, Rifampin, Rifapentine, St john's wort. The full list is on the Sofosbuvir-velpatasvir page.
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