Complex sentence: Metamizole was banned in Sweden in 1974, in the United States in 1977; more than 30 countries, including Japan, Australia, Iran, and part of the European Union, have followed suit.
Split into simpler sentences: Metamizole was banned in Sweden in 1974, in the United States in 1977. Since then, more than 30 countries (including Japan, Australia, Iran, and several of the European Union member nations) have followed suit.