What the FDA labels say about taking them together
Clozapine and insulin glargine
Insulin glargine's FDA label of June 16, 2026 names clozapine in its drug interactions section; the clozapine labels PlainMeds reads (2) do not name insulin glargine. The insulin glargine label: “Drugs that May Decrease the Blood Glucose Lowering Effect of Insulin Glargine-yfgn Drugs: Atypical antipsychotics, corticosteroids, danazol, diuretics, estrogens, glucagon, isoniazid, niacin, oral contraceptives …”
Check it at the source: the clozapine FDA label on DailyMed (effective June 6, 2025, HLS Therapeutics (USA), Inc.); the insulin glargine FDA label on DailyMed (effective June 16, 2026, Eli Lilly and Company).
What does the clozapine label say about insulin glargine?
Clozapine's label (effective June 6, 2025) and its 1 other brand-application label do not name insulin glargine in these sections. A label lists what its studies and reports found; it is not a complete list.
Source: FDA drug label (Clozaril), NDA019758 (Heritage Life), as published by HLS Therapeutics (USA), Inc., effective June 6, 2025 (SPL set 90876802-0e3a-44c9-9ff7-1754dfbe736a), via openFDA; the full label on DailyMed
What does the insulin glargine label say about clozapine?
Insulin glargine label, drug interactionsDrugs That May Decrease the Blood Glucose Lowering Effect of BASAGLAR Drugs: 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), and thyroid hormones Intervention: Dose increases and increased frequency of glucose monitoring may be required when BASAGLAR is co-administered with these drugs.
Source: FDA drug label (Insulin Glargine, BLA761201), Biocon Biologics Inc., effective January 23, 2026 (SPL set 3ac85ebb-5594-59c8-77fd-df254329d151), via openFDA
Source: FDA drug label (Lantus Solostar, BLA021081), sanofi-aventis U.S. LLC, effective June 2, 2025 (SPL set d5e07a0c-7e14-4756-9152-9fea485d654a), via openFDA
Source: FDA drug label (Toujeo, BLA206538), Sanofi-Aventis U.S. LLC, effective May 30, 2025 (SPL set c9561d96-124d-48ca-982f-0aa1575bff36), via openFDA
Source: FDA drug label (BASAGLAR KwikPen), Eli Lilly and Company, effective June 16, 2026 (SPL set 0ad21db3-2b1c-4ed9-a687-bdd6a74d0aae), 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
| Clozapine | Insulin glargine | |
|---|---|---|
| Labeled for | Schizophrenia | Type 2 diabetes, Type 1 diabetes |
| Boxed warning | Yes | No |
| Pharmacy cost (NADAC) | $0.610 per tablet 100 mg tablet | $2.90 per mL 100 pen |
| Shortage now | No current entry | A presentation being discontinued |
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