Potential for bleeding with the new beta-lactam antibiotics

Ann Intern Med. 1986 Dec;105(6):924-31. doi: 10.7326/0003-4819-105-6-924.


Several new beta-lactam antibiotics impair normal hemostasis. Hypoprothrombinemia has occurred frequently with cephalosporins that possess a methylthiotetrazole substitution (cefamandole, moxalactam, and cefoperazone). The incidence ranges from 4% to 68%, and the risk is greatest in debilitated patients with cancer, intra-abdominal infection, or renal failure. Impaired platelet function caused by perturbation of agonist receptors on the platelet surface has occurred primarily with beta-lactam antibiotics having an alpha-carboxyl substitution (moxalactam, carbenicillin, and ticarcillin). These antibiotics often cause the template bleeding time to be markedly prolonged (greater than 20 minutes). Acylureidopenicillins, which lack the alpha-carboxyl marker, impair platelet function less frequently and only modestly prolong the bleeding time. If serious hemorrhage occurs, hypoprothrombinemia associated with methylthiotetrazole-substituted cephalosporins should be treated with fresh frozen plasma. Likewise, dangerous bleeding due to impaired platelet aggregation requires treatment with platelet concentrates.

Publication types

  • Review

MeSH terms

  • Anti-Bacterial Agents / adverse effects*
  • Hemorrhage / chemically induced*
  • Hemorrhage / therapy
  • Humans
  • Hypoprothrombinemias / chemically induced
  • Platelet Aggregation / drug effects
  • Risk
  • Tetrazoles / adverse effects
  • Vitamin K / metabolism
  • beta-Lactams


  • Anti-Bacterial Agents
  • Tetrazoles
  • beta-Lactams
  • Vitamin K
  • 1-N-methyl-5-thiotetrazole