text: In medicine, phosphonates and bisphosphonates are commonly used as inhibitors of enzymes which utilize phosphates and diphosphates as substrates. Most notably, these enzymes include those that produce the intermediates of cholesterol biosynthesis.
  Phosphonate nucleotide analogues such as tenofovir, cidofovir and adefovir are critical antiviral medications, which in various pro-drug forms are used for the treatment of HIV, hepatitis B and others.