Contact dermatitis caused by intermediate products in the manufacture of clenbuterol, ranitidine base, and ranitidine hydrochloride.

Clenbuterol, a beta antagonist, and ranitidine, a histamine-receptor antagonist, were associated with contact dermatitis in a chemist. The allergen in the former was an intermediate in the synthesis called beta. In the latter, intermediates and the finished base and hydrochloride were responsible.