Drug interactions
Phenytoin + Tolazamide
Severity: Minor
Phenytoin and Tolazamide: minor 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
Sulfonylureas may raise free phenytoin levels, while phenytoin may reduce the effect of sulfonylureas. The combination could affect both seizure control and glycemic control, though the effect is generally small.
What this interaction means in plain words
Phenytoin and Tolazamide have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised.
Phenytoin belongs to Central Nervous System; Tolazamide belongs to Endocrine.
Why it happens
Possible displacement of phenytoin from plasma proteins and inhibition of its metabolism by tolazamide.
What to do
Monitor blood glucose and signs of phenytoin toxicity such as nystagmus or ataxia. Check free phenytoin levels if toxicity is suspected.
What to ask your pharmacist
- Is there anything I should notice while taking both?
- Do I need to tell my doctor at the next visit?
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Other interactions of Phenytoin
- Artemether / lumefantrine + Phenytoin Contraindicated
- Bictegravir + Phenytoin Contraindicated
- Cabotegravir + Phenytoin Contraindicated
- Doravirine + Phenytoin Contraindicated
- Elbasvir / grazoprevir + Phenytoin Contraindicated
- Elvitegravir / cobicistat / emtricitabine / tenofovir df + Phenytoin Contraindicated
Other interactions of Tolazamide
- Disopyramide + Tolazamide Major
- Insulin degludec-liraglutide + Tolazamide Major
- Aceclofenac + Tolazamide Moderate
- Acemetacin + Tolazamide Moderate
- Acetylsalicylic acid + Tolazamide Moderate
- Albiglutide + Tolazamide Moderate
Frequently asked questions
Can I take Phenytoin with Tolazamide?
MediHelp rates the interaction as minor. Phenytoin and Tolazamide have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised. Sulfonylureas may raise free phenytoin levels, while phenytoin may reduce the effect of sulfonylureas. The combination could affect both seizure control and glycemic control, though the effect is generally small.
How serious is the interaction between Phenytoin and Tolazamide?
MediHelp rates it minor, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor blood glucose and signs of phenytoin toxicity such as nystagmus or ataxia. Check free phenytoin levels if toxicity is suspected.
What other medicines interact with Phenytoin?
MediHelp also lists interactions of Phenytoin with, for example, Artemether / lumefantrine, Bictegravir, Cabotegravir. The full list is on the Phenytoin page.
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