What the FDA labels say about taking them together
Lapatinib ditosylate and paclitaxel
Lapatinib ditosylate's FDA label of November 30, 2023 names paclitaxel in its drug interactions section; the paclitaxel labels PlainMeds reads (4) do not name lapatinib ditosylate. The lapatinib ditosylate label: “In cancer patients receiving TYKERB and paclitaxel, 24-hour systemic exposure (AUC) of paclitaxel was increased 23%.”
Check it at the source: the lapatinib ditosylate FDA label on DailyMed (effective November 30, 2023, Teva Pharmaceuticals, Inc.); the paclitaxel FDA label on DailyMed (effective January 21, 2026, Natco Pharma USA LLC).
What does the lapatinib ditosylate label say about paclitaxel?
Lapatinib ditosylate label, drug interactionsIn cancer patients receiving lapatinib and paclitaxel (CYP2C8 and P-gp substrate), 24-hour systemic exposure (AUC) of paclitaxel was increased 23%.
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 paclitaxel label say about lapatinib ditosylate?
Paclitaxel's label (effective January 21, 2026) 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 (Paclitaxel), Natco Pharma USA LLC, effective January 21, 2026 (SPL set a1eb16b4-285b-4e81-9c4e-1244d4a52af8), 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 | Paclitaxel | |
|---|---|---|
| Labeled for | Breast cancer | Breast cancer, Lung cancer |
| Boxed warning | Yes | Yes |
| Pharmacy cost (NADAC) | n/a | n/a |
| 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