I don't think it's the case that there are many conditions with only single treatment option. "Lower the price or we let our people die" probably isn't right, but "Our cost benefit analysis shows, at this price point, therapy X is preferable. If you want us to use your drug your prices need to be lower."

Presumably the government also has the option to permit purchase of pharmaceuticals from other countries. "Oh, you've raised the cost of X? That's okay, we'll buy it from licensed suppliers in the EU for a tenth of the price."