What the FDA labels say about taking them together
Fluorouracil and levoleucovorin
Levoleucovorin's FDA label of August 29, 2023 names fluorouracil in its drug interactions section; the fluorouracil labels PlainMeds reads (4) do not name levoleucovorin. The levoleucovorin label: “Fluorouracil Leucovorin products increase the toxicity of fluorouracil.”
Check it at the source: the fluorouracil FDA label on DailyMed (effective January 19, 2026, Eugia US LLC); the levoleucovorin FDA label on DailyMed (effective August 29, 2023, Slate Run Pharmaceuticals).
What does the fluorouracil label say about levoleucovorin?
Fluorouracil's label (effective January 19, 2026) and its 3 other brand-application labels do not name levoleucovorin in these sections. A label lists what its studies and reports found; it is not a complete list.
Source: FDA drug label (FLUOROURACIL), Eugia US LLC, effective January 19, 2026 (SPL set 697816ce-dc05-4943-b7f0-2f0b125e93b7), via openFDA; the full label on DailyMed
What does the levoleucovorin label say about fluorouracil?
Levoleucovorin label, drug interactionsFluorouracil Leucovorin products increase the toxicity of fluorouracil.
Levoleucovorin label, warnings and precautionsWARNINGS AND PRECAUTIONS Hypercalcemia: Due to calcium content, inject no more than 16 mL (160 mg) of levoleucovorin solution intravenously per minute. ( 5.1 ) Increased Gastrointestinal Toxicities with Fluorouracil:
Khapzory label (Acrotech Biopharma Inc, March 17, 2026), warnings and precautionsWARNINGS AND PRECAUTIONS Increased Gastrointestinal Toxicities with Fluorouracil: Do not initiate or continue therapy with KHAPZORY and fluorouracil in patients with symptoms of gastrointestinal toxicity until symptoms have resolved.
Source: FDA drug label (Khapzory, NDA211226), Acrotech Biopharma Inc, effective March 17, 2026 (SPL set 344f65ac-9f04-49d7-b7c3-4ba19bd7b429), via openFDA
Source: FDA drug label (LEVOLEUCOVORIN CALCIUM), Slate Run Pharmaceuticals, effective August 29, 2023 (SPL set 124bc214-62f8-40f9-a227-a35e2d1ff2a0), 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
| Fluorouracil | Levoleucovorin | |
|---|---|---|
| Labeled for | Colorectal cancer | Colorectal cancer |
| Boxed warning | Yes | No |
| Pharmacy cost (NADAC) | $0.616 per gram 5% cream | 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