Long-acting beta-2 agonist (LABA)
Formoterol and grapefruit: a real interaction?
Grapefruit is famous as the juice that interacts with medications, and the warning is real for a number of drugs. Whether it matters specifically for Formoterol (Formoterol) at 80/4.5 mcg, 160/4.5 mcg, 200/6 mcg, 400/12 mcg depends on whether the active ingredient Formoterol is metabolised by CYP3A4 in the gut wall and how much that pathway contributes to first-pass metabolism.
The CYP3A4 mechanism
Grapefruit (and its juice) inhibits CYP3A4 enzymes in the gut wall, increasing the absorbed dose of medications metabolised by that enzyme. For drugs in the Long-acting beta-2 agonist (LABA) class that go through CYP3A4 first-pass metabolism, regular grapefruit consumption can raise plasma levels of Formoterol by a clinically meaningful margin and amplify side effects.
What to do with Formoterol
According to the prescribing information for Formoterol, if grapefruit is flagged as an interaction, the safest practice is to avoid grapefruit entirely or to discuss timing with the prescriber. Formoterol selectively activates beta-2 adrenergic receptors on airway smooth muscle, producing bronchodilation through cyclic AMP-mediated relaxation. A small occasional serving may be tolerable; daily large servings around the time of Formoterol dosing are not recommended at 80/4.5 mcg, 160/4.5 mcg, 200/6 mcg, 400/12 mcg.
Frequently asked questions
Can I eat grapefruit while on Formoterol? ▾
For some Long-acting beta-2 agonist (LABA) medications, grapefruit is best avoided or limited because of CYP3A4 inhibition. Whether Formoterol specifically is affected depends on Formoterol; the prescribing information lists this. When in doubt, ask the pharmacist or check the patient leaflet.
How much grapefruit is too much with Formoterol? ▾
For drugs where the interaction matters, even modest daily grapefruit intake (one whole grapefruit or one large glass of juice) can shift drug levels noticeably. For Formoterol at 80/4.5 mcg, 160/4.5 mcg, 200/6 mcg, 400/12 mcg, individual tolerance varies; the cautious choice is to avoid grapefruit if any interaction is mentioned.
Products containing Formoterol
More on Formoterol
- With alcoholFormoterol and alcohol — is it safe to drink?
- With foodShould Formoterol be taken with food?
- Side effectsFormoterol side effects: common, rare and warning signs
- Dosage guideFormoterol dosage guide: how much to take and when
- OnsetHow fast does Formoterol start working?
- DurationHow long does Formoterol last?
The information on this website is provided for reference and educational purposes only. It does not replace consultation with a qualified healthcare professional.