What the FDA labels say about taking them together
Clarithromycin and thiotepa
Thiotepa's FDA label of January 30, 2026 names clarithromycin in its drug interactions section; the clarithromycin label PlainMeds reads does not name thiotepa. The thiotepa label: “Avoid co-administration of strong CYP3A4 inhibitors and strong CYP3A4 inducers with TEPADINA due to the potential effects on efficacy and toxicity.”
Check it at the source: the clarithromycin FDA label on DailyMed (effective April 9, 2026, Solaris Pharma Corporation); the thiotepa FDA label on DailyMed (effective January 30, 2026, Amneal Pharmaceuticals LLC).
What does the clarithromycin label say about thiotepa?
Clarithromycin's label (effective April 9, 2026) does not name thiotepa in these sections. A label lists what its studies and reports found; it is not a complete list.
Source: FDA drug label (Clarithromycin), Solaris Pharma Corporation, effective April 9, 2026 (SPL set 4d42821d-ce7a-7d64-e063-6294a90a0875), via openFDA; the full label on DailyMed
What does the thiotepa label say about clarithromycin?
Thiotepa label, drug interactionsAvoid co-administration of strong CYP3A4 inhibitors (e.g., itraconazole, clarithromycin, ritonavir) and strong CYP3A4 inducers (e.g., rifampin, phenytoin) with TEPADINA due to the potential effects on efficacy and toxicity [see Clinical Pharmacology ( 12.3 ) ].
Source: FDA drug label (TEPADINA), NDA208264 (Adienne Sa), as published by Amneal Pharmaceuticals LLC, effective January 30, 2026 (SPL set 559e353c-2dc0-16ba-e054-00144ff8d46c), 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
| Clarithromycin | Thiotepa | |
|---|---|---|
| Labeled for | Bacterial infections, Acid reflux and ulcers | Organ transplant rejection |
| Boxed warning | No | Yes |
| Pharmacy cost (NADAC) | $0.466 per tablet 500 mg tablet | 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