What the FDA labels say about taking them together
Mavacamten and nirmatrelvir/ritonavir
Nirmatrelvir/ritonavir's FDA label of February 19, 2026 names mavacamten in its drug interactions section; the mavacamten label PlainMeds reads does not name nirmatrelvir/ritonavir. The nirmatrelvir/ritonavir label: “Drug Class: mavacamten; Drugs within Class: ↑ mavacamten; Effect on Concentration: Co-administration with mavacamten may increase mavacamten plasma concentration and increase the risk of heart failure. …”
Check it at the source: the mavacamten FDA label on DailyMed (effective April 17, 2025, Myokardia, Inc.); the nirmatrelvir/ritonavir FDA label on DailyMed (effective February 19, 2026, Pfizer Laboratories Div Pfizer Inc).
What does the mavacamten label say about nirmatrelvir/ritonavir?
Mavacamten's label (effective April 17, 2025) does not name nirmatrelvir/ritonavir in these sections. A label lists what its studies and reports found; it is not a complete list.
Source: FDA drug label (CAMZYOS), NDA214998 (Bristol), as published by Myokardia, Inc., effective April 17, 2025 (SPL set 669c936b-3ee6-4e36-8a22-79dd11b1255b), via openFDA; the full label on DailyMed
What does the nirmatrelvir/ritonavir label say about mavacamten?
Nirmatrelvir/ritonavir label, drug interactionsDrug Class: mavacamten; Drugs within Class: ↑ mavacamten; Effect on Concentration: Co-administration with mavacamten may increase mavacamten plasma concentration and increase the risk of heart failure. Discontinue mavacamten for the duration of PAXLOVID treatment. Resumption of mavacamten within 5 days of completing PAXLOVID may result in higher exposure of mavacamten. Refer to the mavacamten prescribing information for more information.
Source: FDA drug label (Paxlovid), Pfizer Laboratories Div Pfizer Inc, effective February 19, 2026 (SPL set 8a99d6d6-fd9e-45bb-b1bf-48c7f761232a), 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
| Mavacamten | Nirmatrelvir/ritonavir | |
|---|---|---|
| Labeled for | n/a | COVID-19 |
| Boxed warning | Yes | Yes |
| Pharmacy cost (NADAC) | n/a | $49.24 per unit 300-100 mg dose pack |
| 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