The induction of methaemoglobin by p-aminophenones

Four aminophenones were administered to dogs. Orally p-aminopropiophenone (PAPP) was the most effective methaemoglobin former, while p-aminoheptanoylphenone (PAHpP) was the least effective. p-Aminovalerylphenone (PAVP) and p-aminohexanoylphenone (PAHP) were of intermediate efficacy. With oral PAPP, PAVP and PAHP there was no clear cut relationship between acyl chain length and the timing of peak mean methaemoglobin levels. When PAPP or PAHP were administered intravenously the latter produced lower and later peak methaemoglobin levels than the former.