Drug interactions
Lisdexamfetamine + Phenylephrine
Severity: Moderate
Lisdexamfetamine 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
Lisdexamfetamine is converted to dextroamphetamine, which raises blood pressure and heart rate. Adding phenylephrine can further increase blood pressure and the risk of arrhythmia, particularly in patients with cardiovascular disease.
What this interaction means in plain words
Lisdexamfetamine 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.
Lisdexamfetamine belongs to Central Nervous System; Phenylephrine belongs to Respiratory.
Why it happens
Additive sympathomimetic effects: amphetamine-induced norepinephrine release plus direct alpha-1 agonism by phenylephrine.
What to do
Monitor blood pressure and heart rate. Avoid decongestants containing phenylephrine in patients with hypertension or heart 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?
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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 Lisdexamfetamine
- Isocarboxazid + Lisdexamfetamine Contraindicated
- Linezolid + Lisdexamfetamine Contraindicated
- Lisdexamfetamine + Phenelzine Contraindicated
- Lisdexamfetamine + Procarbazine Contraindicated
- Lisdexamfetamine + Rasagiline Contraindicated
- Lisdexamfetamine + Safinamide Contraindicated
Frequently asked questions
Can I take Lisdexamfetamine with Phenylephrine?
MediHelp rates the interaction as moderate. Lisdexamfetamine 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. Lisdexamfetamine is converted to dextroamphetamine, which raises blood pressure and heart rate. Adding phenylephrine can further increase blood pressure and the risk of arrhythmia, particularly in patients with cardiovascular disease.
How serious is the interaction between Lisdexamfetamine 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. Avoid decongestants containing phenylephrine in patients with hypertension or heart 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.
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