Drug-induced blood dyscrasias.

Categories of undesirable effects of drugs are described. Recent experiments on the production of hypersensitization (1) by the use of ECT solution to enhance skin sensitization to penicillin, (2) through the activity of common metabolites of different drugs, and (3) to a non-sensitizing drug by pretreatment with a sensitizing agent are reviewed. The mechanism of hemolytic anemia due to an inherited enzymatic defect and that of drug-induced purpura and the agranulocytic agents is discussed. The three groups of drugs-(1) rarely toxic, e.g. quinine; (2) always toxic in sufficient amounts, e.g. nitrogen mustard; (3) intermediate, e.g. chloramphenicol-are presented, with special consideration of chloramphenicol. It is the responsibility of the pharmacologist to develop and adopt newer methods for toxicity detection, and of the clinician to practise caution in prescribing drugs and to attempt the early recognition of any disorder they may induce. The incidence, diagnosis, prevention, treatment and prognosis of the drug-induced dyscrasias are discussed.