Drug interactions
Insulin isophane protamine human + Tolbutamide
Severity: Moderate
Insulin isophane protamine human 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 with NPH insulin produces additive glucose lowering and increases hypoglycemia risk. Doses of either agent may need reduction.
What this interaction means in plain words
Insulin isophane protamine human 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.
Insulin isophane protamine human belongs to Endocrine; Tolbutamide belongs to Endocrine.
Why it happens
Additive effect of exogenous insulin and sulfonylurea-stimulated pancreatic insulin secretion.
What to do
Monitor glucose frequently after starting or changing doses and reduce insulin or tolbutamide if hypoglycemia occurs.
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 Insulin isophane protamine human
- Ethanol + Insulin isophane protamine human Major
- Insulin isophane protamine human + Pioglitazone Major
- Insulin isophane protamine human + Rosiglitazone Major
- Acarbose + Insulin isophane protamine human Moderate
- Albiglutide + Insulin isophane protamine human Moderate
- Alogliptin + Insulin isophane protamine human Moderate
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 isophane protamine human with Tolbutamide?
MediHelp rates the interaction as moderate. Insulin isophane protamine human 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 with NPH insulin produces additive glucose lowering and increases hypoglycemia risk. Doses of either agent may need reduction.
How serious is the interaction between Insulin isophane protamine human 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 glucose frequently after starting or changing doses and reduce insulin or tolbutamide if hypoglycemia occurs.
What other medicines interact with Insulin isophane protamine human?
MediHelp also lists interactions of Insulin isophane protamine human with, for example, Ethanol, Pioglitazone, Rosiglitazone. The full list is on the Insulin isophane protamine human page.
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