Drug interactions
Lisdexamfetamine + Phentermine
Severity: Major
Lisdexamfetamine 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 combined use increases the risk of hypertension, tachycardia, palpitations, insomnia and anxiety. Using two anorectic stimulants also raises misuse potential.
What this interaction means in plain words
Lisdexamfetamine 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.
Lisdexamfetamine belongs to Central Nervous System; Phentermine belongs to Central Nervous System.
Why it happens
Additive sympathomimetic effects from catecholamine release.
What to do
Avoid combining the two stimulants where possible. If both are used, monitor blood pressure, heart rate and psychiatric 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?
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Other interactions of Lisdexamfetamine
- Isocarboxazid + Lisdexamfetamine Contraindicated
- Linezolid + Lisdexamfetamine Contraindicated
- Lisdexamfetamine + Phenelzine Contraindicated
- Lisdexamfetamine + Procarbazine Contraindicated
- Lisdexamfetamine + Rasagiline Contraindicated
- Lisdexamfetamine + 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 Lisdexamfetamine with Phentermine?
MediHelp rates the interaction as major. Lisdexamfetamine 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 combined use increases the risk of hypertension, tachycardia, palpitations, insomnia and anxiety. Using two anorectic stimulants also raises misuse potential.
How serious is the interaction between Lisdexamfetamine 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 stimulants where possible. If both are used, monitor blood pressure, heart rate and psychiatric symptoms closely.
What other medicines interact with Lisdexamfetamine?
MediHelp also lists interactions of Lisdexamfetamine with, for example, Isocarboxazid, Linezolid, Phenelzine. The full list is on the Lisdexamfetamine page.
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