Drug interactions
Isoproterenol + Phenylephrine
Severity: Moderate
Isoproterenol and Phenylephrine: 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
Both drugs stimulate the cardiovascular system by different adrenergic routes. Combined use can produce tachycardia, arrhythmias and unpredictable changes in blood pressure.
What this interaction means in plain words
Isoproterenol and Phenylephrine 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.
Isoproterenol belongs to Respiratory; Phenylephrine belongs to Respiratory.
Why it happens
Additive adrenergic effects: phenylephrine is an alpha-1 agonist and isoproterenol a non-selective beta agonist.
What to do
Use only with continuous ECG and blood pressure monitoring. Reduce the dose of either agent if arrhythmia or excessive heart rate develops.
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 Phenylephrine
- Isocarboxazid + Phenylephrine Contraindicated
- Phenelzine + Phenylephrine Contraindicated
- Phenylephrine + Tranylcypromine Contraindicated
- Bromocriptine + Phenylephrine Major
- Cocaine + Phenylephrine Major
- Dihydroergotamine intranasal + Phenylephrine Major
Other interactions of Isoproterenol
Frequently asked questions
Can I take Isoproterenol with Phenylephrine?
MediHelp rates the interaction as moderate. Isoproterenol and Phenylephrine 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. Both drugs stimulate the cardiovascular system by different adrenergic routes. Combined use can produce tachycardia, arrhythmias and unpredictable changes in blood pressure.
How serious is the interaction between Isoproterenol and Phenylephrine?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Use only with continuous ECG and blood pressure monitoring. Reduce the dose of either agent if arrhythmia or excessive heart rate develops.
What other medicines interact with Phenylephrine?
MediHelp also lists interactions of Phenylephrine with, for example, Isocarboxazid, Phenelzine, Tranylcypromine. The full list is on the Phenylephrine page.
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