Formoterol and Phenylephrine interaction
Formoterol and Phenylephrine: both prescribing labels flag this combination with the strongest language, such as a contraindication, a boxed warning, or an instruction to avoid it.
Do not combine without a prescriber's guidance. The label language below is the strongest FDA uses.
What the FDA labels say
From the Formoterol (FORMOTEROL FUMARATE) label · effective 2020-12-15
The increased risk of asthma-related death is considered a class effect of the long-acting beta 2 -adrenergic agonists, including formoterol fumarate inhalation solution.
Clinically significant cardiovascular effects and fatalities have been reported in association with excessive use of inhaled sympathomimetic drugs.
• Use with caution in patients with cardiovascular or convulsive disorders, thyrotoxicosis, or with sensitivity to sympathomimetic drugs.
• Use of long-acting beta 2 -adrenergic agonists (LABA) as monotherapy [without inhaled corticosteroids (ICS)] for asthma is associated with an increased risk of asthma-related death.
Therefore, formoterol fumarate inhalation solution, like other sympathomimetic amines, should be used with caution in patients with cardiovascular disorders, especially coronary insufficiency, cardiac arrhythmias, and hypertension.
From the Phenylephrine (Biorphen) label · effective 2026-03-31
Pressor Effect with Concomitant Oxytocic Drugs Oxytocic drugs potentiate the increasing blood pressure effect of sympathomimetic pressor amines including BIORPHEN [see Drug Interactions (7.1) ] , with the potential for hemorrhagic stroke.
Taking more than these two? Interactions stack. Check your whole list at once; it stays in your browser.
Open in the checkerNot medical advice. Interaction Checker quotes FDA label text and NIH fact sheets. Whether an interaction matters for you depends on doses, timing, kidney and liver function, and other conditions. Confirm with a pharmacist or prescriber.