Vonoprazan fumarate is a pyrrole derivative and potassium-competitive acid blocker (P-CAB) that competitively blocks the potassium-binding site of gastric H(+), K(+)-ATPase, a key enzyme involved in gastric acid secretion.
It is used for the treatment of gastric ulcer, duodenal ulcer, reflux esophagitis, and prevention of recurrence of gastric or duodenal ulcer during low-dose aspirin or NSAID administration. It is also used as an adjunct to Helicobacter pylori eradication in the following conditions: gastric ulcer, duodenal ulcer, gastric mucosa-associated lymphatic tissue (MALT) lymphoma, idiopathic thrombocytopenic purpura, the stomach after endoscopic resection of early-stage gastric cancer, or Helicobacter pylori gastritis.
Gastric ulcer, duodenal ulcer: The usual adult dosage is 20 mg of Vonoprazan administered orally once daily for 8 weeks (gastric ulcer) or 6 weeks (duodenal ulcer).
Reflux esophagitis: The usual adult dosage is 20 mg of Vonoprazan administered orally once daily for 4 weeks. If insufficient, the treatment may be extended up to 8 weeks. For maintenance therapy of recurrent reflux esophagitis, the dose is 10 mg once daily, increasing to 20 mg if efficacy is inadequate.
Prevention of gastric or duodenal ulcer recurrence during low-dose aspirin or NSAID administration: 10 mg of Vonoprazan once daily.
Adjunct to Helicobacter pylori eradication:
A three-drug regimen administered orally twice daily for seven days: 20 mg Vonoprazan, 750 mg amoxicillin hydrate, and 200 mg clarithromycin.
If the clarithromycin-based regimen fails, a three-drug regimen of 20 mg Vonoprazan, 750 mg amoxicillin hydrate, and 250 mg metronidazole can be used.
Hypersensitivity to the active substance or any excipients.
Co-administration with Atazanavir or Rilpivirine.
Use with caution in patients with severe liver dysfunction or severe renal impairment.
Long-term use (over one year) may slightly increase the risk of hip, wrist, and spine fractures.
The most common adverse reactions include constipation, diarrhea, skin rash, and nausea.
Breastfeeding is not recommended during treatment. Lactating women can pump and discard breast milk during treatment and for two days after Vonoprazan administration.
The safety and effectiveness of Vonoprazan in pediatric patients have not been established.
Vonoprazan is metabolized by CYP2C19 and CYP3A4 enzymes. It may reduce the clearance of diazepam and increase plasma levels of diazepam.
Vonoprazan may interfere with the absorption of drugs where gastric pH is critical for bioavailability (e.g., ketoconazole, iron salts, digoxin).
Co-administration with clarithromycin and amoxicillin can increase plasma levels of Vonoprazan and 14-hydroxyclarithromycin.
Store at a temperature not exceeding 30 ºC in a dry place. Protect from light and moisture.
Keep out of reach of children.
Kenzo® Tablet 10 mg: Each film-coated tablet contains Vonoprazan Fumarate INN 13.36 mg, equivalent to Vonoprazan 10 mg.
Kenzo® Tablet 20 mg: Each film-coated tablet contains Vonoprazan Fumarate INN 26.72 mg, equivalent to Vonoprazan 20 mg.
