I’m standing at 9000 feet elevation in the Atacama desert, the driest desert on the planet. You can see the Andes mountains behind me. When I arrived, I went from 2000 feet elevation to 11,000 feet at the first base camp. And I developed all the symptoms of altitude sickness: headache, dizziness, nausea. If you get to the point of confusion, you need to get oxygen and descend immediately. I had Acetazolamide (brand name Diamox). The medication works by causing you to breathe faster which increases the amount of oxygen, and it did relieve my symptoms.
Here in Chile there are also local herbs like chochokama that help with dizziness and nausea, or coca leaves.
But the best thing to do is to acclimate. It takes about a week to adjust, so I recommend that you get to a half-way elevation point and spend a few days there, then go up a little higher.
