Drug interactions
Insulin lispro protamine / insulin lispro + Tolbutamide
Severity: Moderate
Insulin lispro protamine / insulin lispro and Tolbutamide: moderate interaction.
Last updated
For healthcare professionals — reference only. This page is a brief summary, not medical advice and not a substitute for official labeling or clinical judgement. Always verify before prescribing or dispensing.
Summary
Tolbutamide stimulates insulin secretion while exogenous insulin lowers glucose directly, so the combined glucose-lowering effect is additive. Hypoglycemia can occur, especially when either drug is started, increased or when the other is withdrawn.
What this interaction means in plain words
Insulin lispro protamine / insulin lispro and Tolbutamide can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken.
Why it happens
Additive pharmacodynamic glucose-lowering effect from insulin secretagogue action plus exogenous insulin.
What to do
Monitor blood glucose closely when starting, adjusting or stopping either agent and reduce the insulin or tolbutamide dose if hypoglycemia occurs. Educate the patient on recognizing and treating hypoglycemia.
What to ask your pharmacist
- Should I take them at different times of day?
- Does the dose of either medicine need to change?
- Is there anything I should avoid, such as alcohol or certain foods, while on both?
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Other interactions of Tolbutamide
- Glyburide-metformin + Tolbutamide Major
- Insulin degludec-liraglutide + Tolbutamide Major
- Aceclofenac + Tolbutamide Moderate
- Acemetacin + Tolbutamide Moderate
- Acetylsalicylic acid + Tolbutamide Moderate
- Albiglutide + Tolbutamide Moderate
Frequently asked questions
Can I take Insulin lispro protamine / insulin lispro with Tolbutamide?
MediHelp rates the interaction as moderate. Insulin lispro protamine / insulin lispro and Tolbutamide can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken. Tolbutamide stimulates insulin secretion while exogenous insulin lowers glucose directly, so the combined glucose-lowering effect is additive. Hypoglycemia can occur, especially when either drug is started, increased or when the other is withdrawn.
How serious is the interaction between Insulin lispro protamine / insulin lispro and Tolbutamide?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor blood glucose closely when starting, adjusting or stopping either agent and reduce the insulin or tolbutamide dose if hypoglycemia occurs. Educate the patient on recognizing and treating hypoglycemia.
What other medicines interact with Tolbutamide?
MediHelp also lists interactions of Tolbutamide with, for example, Glyburide-metformin, Insulin degludec-liraglutide, Aceclofenac. The full list is on the Tolbutamide page.
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