What the FDA labels say about taking them together
Pyrimethamine and zidovudine
Pyrimethamine's FDA label of December 7, 2023 names zidovudine in its drug interactions section; the zidovudine labels PlainMeds reads (3) do not name pyrimethamine. The pyrimethamine label: “… including sulfonamides or trimethoprim- sulfamethoxazole combinations, proguanil, zidovudine, or cytostatic agents (e.g., methotrexate), while the patient is receiving pyrimethamine, may increase the risk of bone marrow …”
Check it at the source: the pyrimethamine FDA label on DailyMed (effective December 7, 2023, TILDE Sciences LLC); the zidovudine FDA label on DailyMed (effective February 10, 2025, Aurobindo Pharma Limited).
What does the pyrimethamine label say about zidovudine?
Pyrimethamine label, drug interactionsHowever, the concomitant use of other antifolic drugs or agents associated with myelosuppression including sulfonamides or trimethoprim- sulfamethoxazole combinations, proguanil, zidovudine, or cytostatic agents (e.g., methotrexate), while the patient is receiving pyrimethamine, may increase the risk of bone marrow suppression.
Source: FDA drug label (Daraprim), TILDE Sciences LLC, effective December 7, 2023 (SPL set f634f34b-0952-4dd3-9da3-f84b6ab823de), via openFDA; the full label on DailyMed
What does the zidovudine label say about pyrimethamine?
Zidovudine's label (effective February 10, 2025) and its 2 other brand-application labels do not name pyrimethamine in these sections. A label lists what its studies and reports found; it is not a complete list.
Source: FDA drug label (Zidovudine), Aurobindo Pharma Limited, effective February 10, 2025 (SPL set 51abd2ce-6be1-412d-b806-5f24935ac5e3), 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
| Pyrimethamine | Zidovudine | |
|---|---|---|
| Labeled for | n/a | HIV |
| Boxed warning | No | Yes |
| Pharmacy cost (NADAC) | $137.01 per tablet 25 mg tablet | $0.464 per tablet 300 mg tablet |
| 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