Drug interactions
Caffeine + Phenylephrine po
Severity: Moderate
Caffeine and Phenylephrine po: 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
Caffeine and oral phenylephrine may produce additive stimulation with nervousness, palpitations and a modest rise in blood pressure. Patients with hypertension or arrhythmia are most affected.
What this interaction means in plain words
Caffeine and Phenylephrine po 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.
Why it happens
Additive sympathomimetic effects from alpha-1 agonism and caffeine-mediated catecholamine release and adenosine blockade.
What to do
Monitor blood pressure and heart rate in at-risk patients and advise limiting caffeine while using the decongestant.
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 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 Phenylephrine po?
MediHelp rates the interaction as moderate. Caffeine and Phenylephrine po 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. Caffeine and oral phenylephrine may produce additive stimulation with nervousness, palpitations and a modest rise in blood pressure. Patients with hypertension or arrhythmia are most affected.
How serious is the interaction between Caffeine and Phenylephrine po?
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 pressure and heart rate in at-risk patients and advise limiting caffeine while using the decongestant.
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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