Insulin glargine and Phentermine interaction
Insulin glargine and Phentermine: both prescribing labels describe an interaction that usually calls for monitoring, a dose change, or spacing the doses.
Usually manageable with monitoring or a dose change. Tell your pharmacist you take both.
What the FDA labels say
From the Insulin glargine label · effective 2026-01-23
…Glargine-yfgn 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.
From the Phentermine (Phentermine hydrochloride) label · effective 2026-08-17
• A reduction in dose of insulin or oral hypoglycemic medication may be required in some patients.
Use in Patients on Insulin or Oral Hypoglycemic Medications for Diabetes Mellitus A reduction in insulin or oral hypoglycemic medications in patients with diabetes mellitus may be required.
Insulin and Oral Hypoglycemic Medications Requirements may be altered [ see Warnings and Precautions ( 5.9 ) ].
• Insulin and oral hypoglycemics: Requirements may be altered.
Taking more than these two? Interactions stack. Check your whole list at once; it stays in your browser.
Open in the checkerNot medical advice. Interaction Checker quotes FDA label text and NIH fact sheets. Whether an interaction matters for you depends on doses, timing, kidney and liver function, and other conditions. Confirm with a pharmacist or prescriber.