Discussion
Clarithromycin is a first-line drug for H. pylori eradication. It is reportedly a cytochrome P450 3A4 inhibitor, but that is not in and of itself a contraindication for porphyria.5,6 There have been no reports on the safety of metronidazole monotherapy or combination therapy for H. pylori in patients with porphyria; and although amoxicillin and vonoprazan are believed not to induce porphyria attacks, the evidence remains insufficient. We had previously described how porphyria attacks can be triggered by the accumulation of porphyrin precursors or the lack of heme,4 indicating that porphyria attacks may be prevented by supplying the appropriate amount of hemin. Here, we present a protocol that can suppress medication-induced porphyria, even in patients with a history of recurrent acute attacks. More specifically, we believe this report may serve as a future reference for eradicatingH. pylori in patients with porphyria.