Drug interactions
Phendimetrazine + Pseudoephedrine
Severity: Major
Phendimetrazine and Pseudoephedrine: major 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 are sympathomimetic, so combined use can cause excessive increases in blood pressure and heart rate, insomnia, anxiety and arrhythmias. Patients with cardiovascular disease are at higher risk.
What this interaction means in plain words
Phendimetrazine and Pseudoephedrine can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for.
Why it happens
Additive norepinephrine release and adrenergic stimulation from two sympathomimetic agents.
What to do
Avoid the combination where possible and use a non-sympathomimetic option for congestion. If both are used, monitor blood pressure and heart rate.
What to ask your pharmacist
- Does the benefit of taking both outweigh the risk in my case?
- Do I need any blood test, ECG or other check while on both?
- What early warning signs should I watch for, and what should I do if they appear?
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Other interactions of Pseudoephedrine
- Isocarboxazid + Pseudoephedrine Contraindicated
- Phenelzine + Pseudoephedrine Contraindicated
- Pseudoephedrine + Rasagiline Contraindicated
- Pseudoephedrine + Selegiline Contraindicated
- Pseudoephedrine + Selegiline transdermal Contraindicated
- Pseudoephedrine + Tranylcypromine Contraindicated
Frequently asked questions
Can I take Phendimetrazine with Pseudoephedrine?
MediHelp rates the interaction as major. Phendimetrazine and Pseudoephedrine can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for. Both drugs are sympathomimetic, so combined use can cause excessive increases in blood pressure and heart rate, insomnia, anxiety and arrhythmias. Patients with cardiovascular disease are at higher risk.
How serious is the interaction between Phendimetrazine and Pseudoephedrine?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid the combination where possible and use a non-sympathomimetic option for congestion. If both are used, monitor blood pressure and heart rate.
What other medicines interact with Pseudoephedrine?
MediHelp also lists interactions of Pseudoephedrine with, for example, Isocarboxazid, Phenelzine, Rasagiline. The full list is on the Pseudoephedrine page.
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