Eat high-carbohydrate foods. Carbohydrates produce energy faster than do fats. Also, the metabolism of carbohydrates requires less oxygen. Avoid sleeping pills. They can cause shallow breathing while sleeping, making it harder to get enough oxygen.
Smoking also makes it more difficult to get oxygen from lungs to tissue.
Although you can't take a pill to acclimate to altitude, you can take a prescription drug that can reduce the symptoms of altitude sickness. Talk to your doctor about this. Not everyone responds the same way to altitude. Only one in four people going from sea level to 6,000 feet, roughly Denver's altitude, experience one or more symptoms of altitude sickness. But about three in four people who go to 8,000 feet and higher have problems.