Cephapirin sodium (Cefapirin sodium), a semisynthetic cephalosporin antibiotic, is bactericidal against strains of gram-positive and gram-negative bacteria.
Cephapirin is closely resembles cephalothin in chemical and pharmacokinetic properties. Cephapirin, have cephalosporanic acid core with the acetyloxymethyl group at the 3rd position and having IUPAC name (6R,7R)-3-(Acetoxymethy)-8- oxo-7-{[(pyridin-4-ylsulfanyl)acetyl]amino}-5-thia- 1-azabicyclo [4.2.0] oct-2-ene-2-carboxylic acid. It is unstable in acid and must be administered parenteral. It has similar mechanism as other cephalosporins. It is marketed under the trade name Cefadyl. It is effective against a wide variety of gram-positive and gramnegative bacteria; used as the sodium salt. Among the most serious adverse reactions of cefapirin, that is， neutropenia, leukopenia, anemia, bone marrowdepression, and allergic reactions, it has been discontinued in the United States (Wiesner, 1972).
