Drug interactions
Methamphetamine + Phenylephrine
Severity: Moderate
Methamphetamine 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
Methamphetamine is a potent sympathomimetic, and phenylephrine adds direct vasoconstriction. Together they may cause marked hypertension, tachycardia and arrhythmia, especially in patients with underlying heart disease.
What this interaction means in plain words
Methamphetamine 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.
Methamphetamine belongs to Central Nervous System; Phenylephrine belongs to Respiratory.
Why it happens
Additive sympathomimetic effects from norepinephrine release by methamphetamine and direct alpha-1 agonism by phenylephrine.
What to do
Monitor blood pressure and heart rate and avoid phenylephrine decongestants in patients with hypertension or cardiac disease.
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?
Pro+ members
Unlock the full page
Create an account and start a Pro+ trial to unlock the full management advice for Methamphetamine and Phenylephrine, the additional notes, the evidence detail and the whole-prescription interaction checker.
- Full clinical management advice
- Additional notes
- Evidence detail
- Interaction checker for a whole prescription
Try Pro+ free for 7 days on the web. No card needed.
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 Methamphetamine
- Isocarboxazid + Methamphetamine Contraindicated
- Linezolid + Methamphetamine Contraindicated
- Methamphetamine + Phenelzine Contraindicated
- Methamphetamine + Procarbazine Contraindicated
- Methamphetamine + Rasagiline Contraindicated
- Methamphetamine + Safinamide Contraindicated
Frequently asked questions
Can I take Methamphetamine with Phenylephrine?
MediHelp rates the interaction as moderate. Methamphetamine 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. Methamphetamine is a potent sympathomimetic, and phenylephrine adds direct vasoconstriction. Together they may cause marked hypertension, tachycardia and arrhythmia, especially in patients with underlying heart disease.
How serious is the interaction between Methamphetamine 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: Monitor blood pressure and heart rate and avoid phenylephrine decongestants in patients with hypertension or cardiac disease.
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.
Full monographs, dosing and an interaction checker in the MediHelp app
Open the complete reference, check multi-drug interactions and use dosing tools in the MediHelp app.
