Drug interactions
Methamphetamine + Phentermine
Severity: Major
Methamphetamine and Phentermine: 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 stimulants, so using them together produces additive increases in blood pressure and heart rate, along with anxiety and insomnia. There is a greater risk of arrhythmia and of misuse.
What this interaction means in plain words
Methamphetamine and Phentermine 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.
Methamphetamine belongs to Central Nervous System; Phentermine belongs to Central Nervous System.
Why it happens
Additive release of norepinephrine and dopamine, giving summed sympathomimetic effects.
What to do
Avoid combining the two. If concurrent use is unavoidable, monitor blood pressure, heart rate and cardiac symptoms closely.
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?
Pro+ members
Unlock the full page
Create an account and start a Pro+ trial to unlock the full management advice for Methamphetamine and Phentermine, 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 Methamphetamine
- Isocarboxazid + Methamphetamine Contraindicated
- Linezolid + Methamphetamine Contraindicated
- Methamphetamine + Phenelzine Contraindicated
- Methamphetamine + Procarbazine Contraindicated
- Methamphetamine + Rasagiline Contraindicated
- Methamphetamine + Safinamide Contraindicated
Other interactions of Phentermine
- Isocarboxazid + Phentermine Contraindicated
- Linezolid + Phentermine Contraindicated
- Phenelzine + Phentermine Contraindicated
- Phentermine + Procarbazine Contraindicated
- Phentermine + Rasagiline Contraindicated
- Phentermine + Selegiline Contraindicated
Frequently asked questions
Can I take Methamphetamine with Phentermine?
MediHelp rates the interaction as major. Methamphetamine and Phentermine 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 stimulants, so using them together produces additive increases in blood pressure and heart rate, along with anxiety and insomnia. There is a greater risk of arrhythmia and of misuse.
How serious is the interaction between Methamphetamine and Phentermine?
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 combining the two. If concurrent use is unavoidable, monitor blood pressure, heart rate and cardiac symptoms closely.
What other medicines interact with Methamphetamine?
MediHelp also lists interactions of Methamphetamine with, for example, Isocarboxazid, Linezolid, Phenelzine. The full list is on the Methamphetamine 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.
