Grapefruit and Olmesartan?

Hi,

She will be just fine.

What should I avoid while taking olmesartan?
Do not use potassium supplements or salt substitutes, unless your doctor has told you to.

Avoid getting up too fast from a sitting or lying position, or you may feel dizzy.

Source and more info: https://www.drugs.com/mtm/olmesartan.html

Olmesartan and Alcohol/Food Interactions
There are 2 alcohol/food/lifestyle interactions with olmesartan.

Moderate
Alcohol (Ethanol) Olmesartan
Moderate Drug Interaction

Olmesartan and ethanol (alcohol) may have additive effects in lowering your blood pressure. You may experience headache, dizziness, lightheadedness, fainting, and/or changes in pulse or heart rate. These side effects are most likely to be seen at the beginning of treatment, following a dose increase, or when treatment is restarted after an interruption. Let your doctor know if you develop these symptoms and they do not go away after a few days or they become troublesome. Avoid driving or operating hazardous machinery until you know how the medications affect you, and use caution when getting up from a sitting or lying position. It is important to tell your doctor about all other medications you use, including vitamins and herbs. Do not stop using any medications without first talking to your doctor.

Moderate
Olmesartan Food/Lifestyle
Moderate Food Interaction

If you are taking olmesartan you should avoid potassium-containing salt substitutes or over-the-counter potassium supplements without first talking to your doctor. This can cause high levels of potassium in your blood. High levels of potassium can cause weakness, irregular heartbeat, confusion, tingling of the extremities, or feelings of heaviness in the legs. Call your doctor at once if you have any of these symptoms.

Source: https://www.drugs.com/food-interactions/olmesartan.html