Four months after starting vonoprazan, a 64-year-old man developed sudden clonic convulsions (Okamoto et al., 2022) [A]. Seizures were attributed to the patient's previous history of cerebral infarction, and magnesium levels were not obtained. Two years later, the patient was admitted with convulsions and altered consciousness.

Once supplementation is stopped, patients' magnesium levels drop rapidly. On hospital day 5, vonoprazan was discontinued, and magnesium levels stabilized and returned to normal 10 days after discontinuation. Histamine 2 receptor antagonist (H2RA) replaced vonoprazan. Clinicians should be aware of the risk of hypomagnesemia associated with the use of vonoprazan and should consider routine monitoring of patients with inadequate oral intake. Patients with this complication can be transitioned to H2RA.

Prasugrel is also a prodrug that relies primarily on CYP3A4 for conversion to the active form. The results of this crossover study showed that, regardless of the genotype group, due to its CYP2C19 and CYP3A4 inhibitory effects, vonoprazan reduced the median platelet aggregation (IPA) effect of clopidogrel and prasugrel more than esomeprazole. inhibition. IPA was 34%, 33%, and 13% for clopidogrel alone, clopidogrel plus esomeprazole, and clopidogrel plus vonoprazan, respectively. For prasugrel, the median IPA was 59%, 47%, and 37% for prasugrel alone, prasugrel plus esomeprazole, and prasugrel plus vonoprazan, respectively. Esomeprazole did not reduce the inhibitory effect of prasugrel on platelet aggregation, regardless of genotype.