What the FDA labels say about taking them together
Arsenic trioxide and thiamine
Arsenic trioxide's FDA label of July 23, 2021 names thiamine in its boxed warning section; the thiamine label PlainMeds reads does not name arsenic trioxide. The arsenic trioxide label: “Consider testing thiamine levels in patients at risk for thiamine deficiency.”
Check it at the source: the arsenic trioxide FDA label on DailyMed (effective July 23, 2021, Amneal Pharmaceuticals LLC); the thiamine FDA label on DailyMed (effective July 22, 2026, Sagent Pharmaceuticals).
What does the arsenic trioxide label say about thiamine?
Arsenic trioxide label, boxed warningConsider testing thiamine levels in patients at risk for thiamine deficiency.
Arsenic trioxide label, warnings and precautionsWernicke’s encephalopathy is a neurologic emergency that can be prevented and treated with thiamine.
Source: FDA drug label (Arsenic Trioxide), Amneal Pharmaceuticals LLC, effective July 23, 2021 (SPL set 5845022e-8c01-451b-ae49-a28e58c5f845), via openFDA; the full label on DailyMed
What does the thiamine label say about arsenic trioxide?
Thiamine's label (effective July 22, 2026) does not name arsenic trioxide in these sections. A label lists what its studies and reports found; it is not a complete list.
Source: FDA drug label (thiamine hydrochloride), Sagent Pharmaceuticals, effective July 22, 2026 (SPL set 5982cf83-01d6-4acb-8373-339079b8a76e), 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
| Arsenic trioxide | Thiamine | |
|---|---|---|
| Labeled for | Leukemia, lymphoma and myeloma | n/a |
| Boxed warning | Yes | No |
| Pharmacy cost (NADAC) | n/a | $2.25 per mL 200 mg/2 mL vial |
| 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