I went to Peru last year and was told by an elderly doctor that only young people get altitude sickness.
Oh the joys of being old!
None of the over 60s suffered it at all but one 50 year old and some youngsters did.
We went to Macchu Picu which is on top of an Andes mountain.
All hotels provided coca leaf tea and this was the free antidote.
I assume it worked..but I don't think there were any drugs to buy.
no-one seemed to chew the dried leaves and the tea was quite nice.
I do hope you have a wonderful trip and take care to get good travel insurance just in case!