Drug interactions
Formoterol + Phentermine
Severity: Moderate
Formoterol and Phentermine: 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
Both drugs have sympathomimetic activity, so using them together can add to rises in heart rate and blood pressure and increase the risk of palpitations, tremor or arrhythmia. This matters most in patients with cardiovascular disease.
What this interaction means in plain words
Formoterol and Phentermine 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.
Formoterol belongs to Respiratory; Phentermine belongs to Central Nervous System.
Why it happens
Additive adrenergic stimulation, with direct beta-2 agonism from formoterol and indirect sympathomimetic release of catecholamines from phentermine.
What to do
Monitor heart rate, blood pressure and symptoms of palpitations or tremor. Avoid the combination in patients with uncontrolled hypertension or arrhythmia.
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 Formoterol
- Adagrasib + Formoterol Major
- Amiodarone + Formoterol Major
- Amisulpride + Formoterol Major
- Amitriptyline + Formoterol Major
- Amoxapine + Formoterol Major
- Arformoterol + Formoterol Major
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 Formoterol with Phentermine?
MediHelp rates the interaction as moderate. Formoterol and Phentermine 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. Both drugs have sympathomimetic activity, so using them together can add to rises in heart rate and blood pressure and increase the risk of palpitations, tremor or arrhythmia. This matters most in patients with cardiovascular disease.
How serious is the interaction between Formoterol and Phentermine?
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 heart rate, blood pressure and symptoms of palpitations or tremor. Avoid the combination in patients with uncontrolled hypertension or arrhythmia.
What other medicines interact with Formoterol?
MediHelp also lists interactions of Formoterol with, for example, Adagrasib, Amiodarone, Amisulpride. The full list is on the Formoterol page.
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