Drug interactions
Caffeine + Grapefruit
Severity: Minor
Caffeine and Grapefruit: 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
Grapefruit juice may modestly slow caffeine clearance, leading to somewhat higher and longer-lasting caffeine levels. In most people this causes little noticeable change, though caffeine-sensitive patients may have more jitteriness or insomnia.
What this interaction means in plain words
Caffeine and Grapefruit have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised.
Why it happens
Grapefruit constituents may weakly inhibit CYP1A2, the main enzyme metabolizing caffeine.
What to do
No routine action needed; advise caffeine-sensitive patients to reduce caffeine intake if palpitations, tremor or insomnia occur.
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 Caffeine
- Caffeine + Ephedrine Major
- Caffeine + Fezolinetant Major
- Caffeine + Methylenedioxymethamphetamine Major
- Caffeine + Selegiline transdermal Major
- Adenosine + Caffeine Moderate
- Benzphetamine + Caffeine Moderate
Frequently asked questions
Can I take Caffeine with Grapefruit?
MediHelp rates the interaction as minor. Caffeine and Grapefruit have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised. Grapefruit juice may modestly slow caffeine clearance, leading to somewhat higher and longer-lasting caffeine levels. In most people this causes little noticeable change, though caffeine-sensitive patients may have more jitteriness or insomnia.
How serious is the interaction between Caffeine and Grapefruit?
MediHelp rates it minor, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: No routine action needed; advise caffeine-sensitive patients to reduce caffeine intake if palpitations, tremor or insomnia occur.
What other medicines interact with Caffeine?
MediHelp also lists interactions of Caffeine with, for example, Ephedrine, Fezolinetant, Methylenedioxymethamphetamine. The full list is on the Caffeine page.
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