What the FDA labels say about taking them together
Glipizide and isoniazid
Glipizide's FDA label of January 8, 2026 names isoniazid in its drug interactions section; the isoniazid label PlainMeds reads does not name glipizide. The glipizide label: “… antipsychotics, corticosteroids, danazol, diuretics, estrogens, glucagon, isoniazid, niacin, oral contraceptives, phenothiazines, progestogens, protease inhibitors, somatropin, sympathomimetic agents, thyroid hormones …”
Check it at the source: the glipizide FDA label on DailyMed (effective January 8, 2026, Aurobindo Pharma Limited); the isoniazid FDA label on DailyMed (effective July 8, 2025, OMNIVIUM PHARMACEUTICALS LLC.).
What does the glipizide label say about isoniazid?
Glipizide label, drug interactionsThe following are examples of medication that may reduce the glucose-lowering effect of glipizide extended-release tablets, leading to worsening glycemic control: atypical antipsychotics (e.g., olanzapine and clozapine), corticosteroids, danazol, diuretics, estrogens, glucagon, isoniazid, niacin, oral contraceptives, phenothiazines, progestogens (e.g., in oral contraceptives), protease inhibitors, somatropin, sympathomimetic agents (e.g., albuterol, epinephrine, terbutaline), thyroid hormones, phenytoin, nicotinic acid, and calcium channel blocking drugs.
Source: FDA drug label (Glucotrol Xl, NDA020329), Roerig, effective July 21, 2026 (SPL set eed99b60-d043-4249-9b2a-f05e46fb588d), via openFDA
Source: FDA drug label (Glipizide), Aurobindo Pharma Limited, effective January 8, 2026 (SPL set 84794a52-b717-488c-8533-6425c83d405f), via openFDA; the full label on DailyMed
What does the isoniazid label say about glipizide?
Isoniazid's label (effective July 8, 2025) does not name glipizide in these sections. A label lists what its studies and reports found; it is not a complete list.
Source: FDA drug label (isoniazid), OMNIVIUM PHARMACEUTICALS LLC., effective July 8, 2025 (SPL set 35400f1d-fd25-4bfa-a382-ac390e21bf2e), 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
| Glipizide | Isoniazid | |
|---|---|---|
| Labeled for | Type 2 diabetes | n/a |
| Boxed warning | No | Yes |
| Pharmacy cost (NADAC) | $0.0339 per tablet 5 mg tablet | $3.40 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