• C03A Low-ceiling diuretics, thiazides 1 drugs
• C03B Low-ceiling diuretics, excl. thiazides 12 drugs
• C03C High-ceiling diuretics 21 drugs
• C03D Potassium-sparing agents 16 drugs
• C03E Diuretics and potassium-sparing agents in combination 7 drugs
• C03X Other diuretics 3 drugs