Drug interactions
Ritonavir + Tolbutamide
Severity: Moderate
Ritonavir 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
Ritonavir has mixed enzyme effects that may raise or lower tolbutamide exposure, and protease inhibitors can cause insulin resistance and hyperglycemia. Glycemic control may become unpredictable.
What this interaction means in plain words
Ritonavir 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.
Ritonavir belongs to Anti Virals; Tolbutamide belongs to Endocrine.
Why it happens
Variable modulation of CYP2C9 metabolism plus protease inhibitor-induced insulin resistance.
What to do
Monitor blood glucose when ritonavir is started, changed or stopped and adjust the tolbutamide dose according to response.
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
Other interactions of Ritonavir
- Alfuzosin + Ritonavir Contraindicated
- Amiodarone + Ritonavir Contraindicated
- Avanafil + Ritonavir Contraindicated
- Colchicine + Ritonavir Contraindicated
- Dronedarone + Ritonavir Contraindicated
- Eletriptan + Ritonavir Contraindicated
Frequently asked questions
Can I take Ritonavir with Tolbutamide?
MediHelp rates the interaction as moderate. Ritonavir 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. Ritonavir has mixed enzyme effects that may raise or lower tolbutamide exposure, and protease inhibitors can cause insulin resistance and hyperglycemia. Glycemic control may become unpredictable.
How serious is the interaction between Ritonavir 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 when ritonavir is started, changed or stopped and adjust the tolbutamide dose according to response.
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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