Ledipasvir and Famotidine: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Famotidine
Ledipasvir
No brand names on record
How we grade severity & evidence
Severity levels
- Contraindicated: These should generally not be used together.
- Major: Potentially serious — often needs a change or close monitoring.
- Moderate: Can be significant — usually manageable with monitoring.
- Minor: Usually limited clinical impact.
Evidence grades
- Established: Well documented — supported by controlled studies or strong clinical data.
- Probable: Good supporting evidence, though not definitively proven.
- Suspected: Some evidence suggests this interaction, but it is not well established.
- Possible: Limited or conflicting evidence; the interaction may occur.
- Theoretical: Predicted from the drugs' pharmacology; not yet confirmed in people.
Ratings come from the documented interaction literature and are reviewed by a pharmacist. They describe the documented risk of the combination, not what will necessarily happen to you — your dose, timing, and health picture all matter.
What happens
Decreased ledipasvir exposure and loss of efficacy
Interaction Deep Dive
Use caution with coadministration of ledipasvir/sofosbuvir and histamine H2 receptor antagonists (H2-receptor antagonists), as decreased ledipasvir plasma concentrations and loss of efficacy may occur. In drug interaction studies (N=24), ledipasvir Cmax declined by a significant 20% when dosed simultaneously with famotidine. If concurrent use is required, do not exceed an H2-receptor antagonist dose comparable to famotidine 40 mg twice daily, and administer it simultaneously with or 12 hours apart from ledipasvir/sofosbuvir1.
Why it happens (mechanism)
Loss of ledipasvir solubility due to increased pH
Literature reports
1 report — tap to read
a) In 2 drug interaction studies (N=24), Cmax of single-dose of ledipasvir 90 mg declined by a significant 20% when administered simultaneously with single-dose famotidine 40 mg, though the decrease in ledipasvir AUC was nonsignificant. When single-dose famotidine 40 mg was administered 12 hours before single-dose ledipasvir 90 mg, nonsignificant declines in ledipasvir Cmax and AUC occurred 1.
Common questions
Can I take Ledipasvir and Famotidine together?
Decreased ledipasvir exposure and loss of efficacy Always confirm with your pharmacist or prescriber before making any change.
How serious is the Ledipasvir and Famotidine interaction?
It is rated major. Potentially serious — often needs a change or close monitoring.
How quickly could this interaction happen?
The documented onset is "unspecified". The timing of this interaction is not well characterized.
How strong is the evidence for this interaction?
The evidence is graded "theoretical". Predicted from the drugs' pharmacology; not yet confirmed in people.
From our Q&A
Real reader questions about these medications, each personally answered by our pharmacist:
Questions for your pharmacist
- Does my dose of Ledipasvir or Famotidine need adjusting while I take them together?
- What symptoms should prompt me to call you or my prescriber right away?
- Does the timing of my doses matter for this combination?
- Is there a safer alternative to one of these medications for me?
References (1)
- Product Information: HARVONI(R) oral tablets, ledipasvir sofosbuvir oral tablets. Gilead Sciences, Inc. (per manufacturer), Foster City, CA, 2014. DailyMed
Keep reading about Famotidine
Keep reading about Ledipasvir
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Prescription drugs aren't the whole picture — herbal and dietary supplements can interact with them too. From the evidence-graded Natural Medicines database:
major · moderate · minor — check everything you take with our drug–supplement interaction checker.
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