Protoveratrine B is one of two alkaloids isolated from the plant Veratrum albumen. The main effect of both alkaloids is vasodilation in all vascular beds thereby reducing blood pressure. In the 1950's it was recognized that Protoveratrine B is the preferred compound which can be administered at significantly higher doses before the patient begins to vomit.

Protoveratrine A, the principal alkaloid of Veratrum album, has been used in the treatment of hypertension but has largely been replaced by drugs with fewer adverse effects.

Sulfamerazine is a sulfonamide antibiotic, which acts by inhibiting folic acid synthesis in bacterias. The primary target of sulfamerazine is believed to be dihydropteroate synthetase. Sulfamerazine (in comination with Sulfadiazine and Sulfamethazine) was used in the US under different names, including the earliest brand of Neotrizine. Nowdays, the drugs containing sulfamerazine are no longer available for use in humans in the US, however, they may be prescribed for veterinary purposes.