Liver function disturbances after proton pump inhibitors and azathioprine use

Azathioprine is often prescribed as a second choice oral immunosuppressive drug in the treatment of severe atopic dermatitis. Laboratory investigation should be regularly performed during azathioprine treatment because of the potential risk of leucopenia and liver enzyme disturbances. In the three case described, liver enzyme disturbances occurred in patients who were treated with a combination of azathioprine and a proton pump inhibitor. Discontinuation of the proton pump inhibitor and continuation of azathioprine resulted in a normalization of the liver enzymes. Interaction between azathioprine and proton pump inhibitors has not previously been described in literature. Dermatologists should inform patients not to use proton pump inhibitors during azathioprine treatment.© 2014 De Nederlandse Vereniging voor Dermatologie en Venereologie.