What the FDA labels say about taking them together
Carbamazepine and lapatinib ditosylate
Lapatinib ditosylate's FDA label of November 30, 2023 names carbamazepine in its drug interactions section; the carbamazepine labels PlainMeds reads (3) do not name lapatinib ditosylate. The lapatinib ditosylate label: “Inhibit or Induce Cytochrome P450 3A4 Enzymes Lapatinib undergoes extensive metabolism by CYP3A4, and concomitant administration of strong inhibitors or inducers of CYP3A4 alter lapatinib concentrations significantly.”
Check it at the source: the carbamazepine FDA label on DailyMed (effective August 20, 2026, Novartis Pharmaceuticals Corporation); the lapatinib ditosylate FDA label on DailyMed (effective November 30, 2023, Teva Pharmaceuticals, Inc.).
What does the carbamazepine label say about lapatinib ditosylate?
Carbamazepine's label (effective August 20, 2026) and its 2 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 (Tegretol), Novartis Pharmaceuticals Corporation, effective August 20, 2026 (SPL set 8d409411-aa9f-4f3a-a52c-fbcb0c3ec053), via openFDA; the full label on DailyMed
What does the lapatinib ditosylate label say about carbamazepine?
Lapatinib ditosylate label, drug interactionsInhibit or Induce Cytochrome P450 3A4 Enzymes Lapatinib undergoes extensive metabolism by CYP3A4, and concomitant administration of strong inhibitors or inducers of CYP3A4 alter lapatinib concentrations significantly (see Ketoconazole and Carbamazepine sections, below).
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
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
| Carbamazepine | Lapatinib ditosylate | |
|---|---|---|
| Labeled for | Bipolar disorder, Seizures and epilepsy | Breast cancer |
| Boxed warning | Yes | Yes |
| Pharmacy cost (NADAC) | $0.119 per tablet 200 mg tablet | n/a |
| Shortage now | A presentation being discontinued | 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