Drug interactions
Doxepin + Formoterol
Severity: Major
Doxepin and Formoterol: major interaction.
Last updated Sources: US FDA label
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
Doxepin, a tricyclic antidepressant, may potentiate the cardiovascular effects of formoterol and can prolong QT at higher doses. The combination increases risk of tachycardia and arrhythmia.
What this interaction means in plain words
Doxepin and Formoterol 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.
Doxepin belongs to Dermatology; Formoterol belongs to Respiratory.
Why it happens
Tricyclic noradrenaline reuptake inhibition with additive QT prolongation.
What to do
Use extreme caution as per formoterol labeling; monitor ECG and potassium, and use the lowest effective doses or an alternative agent.
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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References
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 Doxepin
- Doxepin + Isocarboxazid Contraindicated
- Doxepin + Phenelzine Contraindicated
- Doxepin + Procarbazine Contraindicated
- Doxepin + Safinamide Contraindicated
- Doxepin + Selegiline Contraindicated
- Doxepin + Tranylcypromine Contraindicated
Frequently asked questions
Can I take Doxepin with Formoterol?
MediHelp rates the interaction as major. Doxepin and Formoterol 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. Doxepin, a tricyclic antidepressant, may potentiate the cardiovascular effects of formoterol and can prolong QT at higher doses. The combination increases risk of tachycardia and arrhythmia.
How serious is the interaction between Doxepin and Formoterol?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Use extreme caution as per formoterol labeling; monitor ECG and potassium, and use the lowest effective doses or an alternative agent.
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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