Do grapefruit and losartan interact?
Yes. Grapefruit can raise the amount of some medicines in your body by interfering with drug metabolism in the gut and liver. Losartan is metabolized in part by CYP enzymes, so grapefruit can potentially increase losartan levels and the effect on blood pressure, which may increase the risk of side effects such as dizziness or low blood pressure.
Is the effect dangerous, or just a blood-pressure concern?
For many people, the main practical risk is stronger blood-pressure lowering than expected. That can lead to lightheadedness, fainting, or kidney-related symptoms if your blood pressure drops too much, especially when you also take other blood-pressure drugs or diuretics.
What should you do if you take losartan and eat grapefruit?
A common safe approach is to avoid grapefruit (and grapefruit juice) while on losartan, or to discuss it with your clinician. If you do eat grapefruit occasionally, pay attention to how you feel after you take your dose (dizziness, weakness, unusually low readings).
Does grapefruit matter for all ARBs the same way?
Not all ARBs have identical metabolism pathways. The grapefruit issue depends on the specific ARB and how it’s processed by the enzymes grapefruit affects. So it’s safer to treat grapefruit-avoidance as a medicine-specific question rather than assuming all ARBs are either equally affected or equally safe.
What symptoms mean you should get help?
Seek medical advice promptly if you have severe dizziness, fainting, confusion, or signs of dehydration, or if your blood pressure readings become consistently very low after starting or changing grapefruit intake.
Sources
I don’t have the provided info needed to cite an authoritative statement here. If you share the specific product/label details you’re working from (brand name, dose, and whether it’s grapefruit fruit or juice), I can help you pinpoint what guidance applies.