Dual 5α-reductase inhibitor (type 1 and type 2)
Dutasteride 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 Dutasteride (Dutasteride) at 0.5mg depends on whether the active ingredient Dutasteride 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 Dual 5α-reductase inhibitor (type 1 and type 2) class that go through CYP3A4 first-pass metabolism, regular grapefruit consumption can raise plasma levels of Dutasteride by a clinically meaningful margin and amplify side effects.
What to do with Dutasteride
According to the prescribing information for Dutasteride, if grapefruit is flagged as an interaction, the safest practice is to avoid grapefruit entirely or to discuss timing with the prescriber. Dutasteride irreversibly inhibits both isoenzymes of 5α-reductase, the enzyme that converts testosterone to dihydrotestosterone (DHT). A small occasional serving may be tolerable; daily large servings around the time of Dutasteride dosing are not recommended at 0.5mg.
Frequently asked questions
Can I eat grapefruit while on Dutasteride? ▾
For some Dual 5α-reductase inhibitor (type 1 and type 2) medications, grapefruit is best avoided or limited because of CYP3A4 inhibition. Whether Dutasteride specifically is affected depends on Dutasteride; the prescribing information lists this. When in doubt, ask the pharmacist or check the patient leaflet.
How much grapefruit is too much with Dutasteride? ▾
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 Dutasteride at 0.5mg, individual tolerance varies; the cautious choice is to avoid grapefruit if any interaction is mentioned.
Products containing Dutasteride
More on Dutasteride
- With alcoholDutasteride and alcohol — is it safe to drink?
- With foodShould Dutasteride be taken with food?
- Side effectsDutasteride side effects: common, rare and warning signs
- Dosage guideDutasteride dosage guide: how much to take and when
- OnsetHow fast does Dutasteride start working?
- DurationHow long does Dutasteride last?
The information on this website is provided for reference and educational purposes only. It does not replace consultation with a qualified healthcare professional.