Drug interactions
Primidone + Tolbutamide
Severity: Moderate
Primidone 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
Primidone is metabolized partly to phenobarbital, an enzyme inducer, and may increase tolbutamide clearance. This can lead to reduced glucose-lowering effect during long-term combined use.
What this interaction means in plain words
Primidone 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.
Primidone belongs to Central Nervous System; Tolbutamide belongs to Endocrine.
Why it happens
Induction of CYP2C9 by primidone and its phenobarbital metabolite accelerates tolbutamide metabolism.
What to do
Monitor glucose when primidone is started, changed or stopped, and adjust the tolbutamide dose as needed.
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 Primidone
- Lorlatinib + Primidone Contraindicated
- Lurasidone + Primidone Contraindicated
- Primidone + Ranolazine Contraindicated
- Primidone + Sofosbuvir-velpatasvir-voxilaprevir Contraindicated
- Primidone + Voriconazole Contraindicated
- Abiraterone + Primidone Major
Frequently asked questions
Can I take Primidone with Tolbutamide?
MediHelp rates the interaction as moderate. Primidone 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. Primidone is metabolized partly to phenobarbital, an enzyme inducer, and may increase tolbutamide clearance. This can lead to reduced glucose-lowering effect during long-term combined use.
How serious is the interaction between Primidone 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 when primidone is started, changed or stopped, and adjust the tolbutamide dose as needed.
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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