What the FDA labels say about taking them together
Lapatinib ditosylate and midazolam
Lapatinib ditosylate's FDA label of November 30, 2023 names midazolam in its drug interactions section; the midazolam labels PlainMeds reads (4) do not name lapatinib ditosylate. The lapatinib ditosylate label: “Following coadministration of lapatinib and midazolam (CYP3A4 substrate), 24-hour systemic exposure (AUC) of orally administered midazolam increased 45%, while 24-hour AUC of intravenously administered midazolam …”
Check it at the source: the lapatinib ditosylate FDA label on DailyMed (effective November 30, 2023, Teva Pharmaceuticals, Inc.); the midazolam FDA label on DailyMed (effective January 1, 2024, Fresenius Kabi USA, LLC).
What does the lapatinib ditosylate label say about midazolam?
Lapatinib ditosylate label, drug interactionsFollowing coadministration of lapatinib and midazolam (CYP3A4 substrate), 24-hour systemic exposure (AUC) of orally administered midazolam increased 45%, while 24-hour AUC of intravenously administered midazolam increased 22%.
Source: FDA drug label (Tykerb, NDA022059), Novartis Pharmaceuticals Corporation, effective January 27, 2026 (SPL set eee37f88-ec6a-4c30-b8aa-e2c71f93088c), via openFDA
Source: FDA drug label (Lapatinib), Teva Pharmaceuticals, Inc., effective November 30, 2023 (SPL set b09abf73-1eef-4e12-b400-c030d546d223), via openFDA; the full label on DailyMed
What does the midazolam label say about lapatinib ditosylate?
Midazolam's label (effective January 1, 2024) and its 3 other brand-application labels do not name lapatinib ditosylate in these sections. A label lists what its studies and reports found; it is not a complete list.
Source: FDA drug label (Midazolam), Fresenius Kabi USA, LLC, effective January 1, 2024 (SPL set 1cc9ba6e-fa1b-405e-9de8-720c567b2a73), 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
| Lapatinib ditosylate | Midazolam | |
|---|---|---|
| Labeled for | Breast cancer | n/a |
| Boxed warning | Yes | Yes |
| Pharmacy cost (NADAC) | n/a | $0.233 per mL 2 mg/2 mL vial |
| Shortage now | No current entry | In shortage |
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