The Hapten Hypothesis

Whilst this may explain potentially explain many cases, this does not represent the full mechanism which is undoubtedly more complex as not all reactions appear to be immunological. For example, paracetamol is known to form reactive intermediates but yet is not involved in idiosyncratic reactions. Indeed, with some notable exceptions such as the penicillins, many drugs involved in idiosyncratic reactions do not mediate their toxicity through a immune response. 

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An alternative theory to the hapten hypothesis that goes some way to explain why not all drugs that form reactive intermediates are associated with idiosyncratic reactions... 

In order to explain the stimulation of an immune response by small drug molecules, Landsteiner in the 1930 s showed that small molecules could stimulate an immune reaction if combined with a protein. This became the hapten hypothesis, that small molecules could be... 

The hapten-hypothesis proposes that sensitizing low molecular weight (i.e. too small to be recognized by T cells directly) drugs conjugate to proteins that... 

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