Dizziness at 1st Rapamycin dose

My mum is on Rapamycin and reported great health benefits. She’s lost 10kg of weight and feels a lot better and more vibrant. She also had lung fibrosis caused by an allergy, which now resolved. Her blood pressure returned to normal from a slightly elevated level. Unfortunately this didn’t last, so she is on low dose ramipril again.

Her rapamycin schedule is 2mg every 14 days with fresh pressed grapefruit juice.

Because of her holiday in September, the Christmas season and because of 2 minor viral nose infections, she decided to pause Rapamycin September 23 to January 24. Note: She cares for a young school child in her household, so infections come and go.

Last week she went back on Rapamycin.

She noted that she didn’t tolerate her 1st dose after the pause. Then she thought about her very first dose in summer 22 and recognized, that she also did not tolerate it then. After taking Rapamycin, she felt dizzy and had to lay down. Like a tingling in the legs raising to the head. In addition her heart rate went up from 65 to 114 bpm.
This only happens with 1st doses, every following dose is tolerated well, no side effects.

Any ideas? I fear the combination with ramipril.

It seems you may be right, there is an interaction when you use the drug interaction checking websites:


I was also dizzy my first time on rapamycin. Just the first time.

A thought for you: I used to take my rapa with grapefruit, too. I stopped, because of how unpredictable the multiplier effect is, and my own side effects.

I might suggest this is too high a dose for her. Try 1mg, no grapefruit, and see how she feels. If that goes well, add another 1mg one or two days later, then however long a washout time you decide.


With my first doses my RHR went up the roof, I felt (euphorically) tired and did not sleep well.
Now the effect is really minimal. RHR goes up, but almost not noticeable, I still feel more tired on the day I take it, but does not interfere with any activity on the day.
I continue taking it trough viral season as in my case it proved to be really protective against viral infections. I am exposed at work all the time to viral infections but haven’t got any since taking rapamycin.


Many thanks for your support! Right, her RHR went up to 114 bpm. That’s frightening! And all of this happened only twice, at the very first Rapamycin dose and after the 4 month pause.

I’m wondering what causes such side effects? Why does it stop with the 2nd dose? If it’s the ramipril, why does it stop? How dangerous is it?

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I even got Apple Watch notification my heart rate is high. Mine went to above 120 but settled down in 45 minutes or so. It did not went up immediately, I took rapamycin in before lunch, went up some 4 hours later and quickly subsided. I still have slightly higher RHR on dosing days… my average is about 55 and it goes to 60-65… I never put any much thought into this, but I suppose it is not dangerous as it is transient and self resolving…