If you double the amount of money in an economy over a period of 5 years, there is simply no avoidance of this. It seems to me that goods ought to cost less over time anyway. In the short run, deflation decreases consumption, but that means it must ultimately increase saving which implies stronger long term growth. Milton Friedman has built a strong empirical case that the money supply actually contracted slightly relative to goods and services during the 1920s. I'm not as familiar with Friedman's quantity theory of money.
Inflation is a rise in the average price level.
Maintaining a stable price level under these conditions must ultimately cause severe distortions, however. If you double the amount of money in an economy over a period of 5 years, there is simply no avoidance of this. It seems to me that goods ought to cost less over time anyway. In the short run, deflation decreases consumption, but that means it must ultimately increase saving which implies stronger long term growth. I'm not as familiar with Friedman's quantity theory of money.