What the FDA labels say about taking them together
Sofosbuvir/velpatasvir/voxilaprevir and sulfasalazine
Sofosbuvir/velpatasvir/voxilaprevir's FDA label of July 14, 2025 names sulfasalazine in its drug interactions section; the sulfasalazine label PlainMeds reads does not name sofosbuvir/velpatasvir/voxilaprevir. The sofosbuvir/velpatasvir/voxilaprevir label: “Coadministration of VOSEVI with BCRP substrates is not recommended.”
Check it at the source: the sofosbuvir/velpatasvir/voxilaprevir FDA label on DailyMed (effective July 14, 2025, Gilead Sciences, Inc.); the sulfasalazine FDA label on DailyMed (effective May 29, 2026, Pfizer Laboratories Div Pfizer Inc).
What does the sofosbuvir/velpatasvir/voxilaprevir label say about sulfasalazine?
Sofosbuvir/velpatasvir/voxilaprevir label, drug interactionsCoadministration of VOSEVI with BCRP substrates (e.g., methotrexate, mitoxantrone, imatinib, irinotecan, lapatinib, rosuvastatin, sulfasalazine, topotecan) is not recommended [see Clinical Pharmacology (12.3) ].
Source: FDA drug label (Vosevi), Gilead Sciences, Inc., effective July 14, 2025 (SPL set 17ffc094-8ca7-45d2-80d8-fd043bc9a221), via openFDA; the full label on DailyMed
What does the sulfasalazine label say about sofosbuvir/velpatasvir/voxilaprevir?
Sulfasalazine's label (effective May 29, 2026) does not name sofosbuvir/velpatasvir/voxilaprevir in these sections. A label lists what its studies and reports found; it is not a complete list.
Source: FDA drug label (Azulfidine), Pfizer Laboratories Div Pfizer Inc, effective May 29, 2026 (SPL set ddbe69f3-bd55-45f3-a64f-f60226c744c4), via openFDA; the full label on DailyMed
These are the labels' own sentences. PlainMeds does not grade interactions; a pharmacist or prescriber can say what they mean for one person's medicines.
Both medicines on the record
| Sofosbuvir/velpatasvir/voxilaprevir | Sulfasalazine | |
|---|---|---|
| Labeled for | Hepatitis C | Crohn's disease and ulcerative colitis, Rheumatoid arthritis |
| Boxed warning | Yes | No |
| Pharmacy cost (NADAC) | n/a | $0.199 per tablet 500 mg tablet |
| Shortage now | No current entry | No current entry |
Source: FDA NDC Directory, CMS NADAC of October 7, 2026 and the FDA Drug Shortage Database (FDA files October 8, 2026)
What next?
- Check more medicines together
- up to five at once