Vonoprazan: Evidence‑Based Dosing, Indications, and Clinical Use

1. Dosing Regimens for GERD and Erosive Esophagitis

• Healing phase: Vonoprazan 20 mg once daily for 8 weeks is the standard regimen for healing erosive esophagitis. 1
• Maintenance phase: After healing, vonoprazan 10 mg once daily maintains remission in severe erosive esophagitis (Los Angeles grade C/D) with a 75‑77 % maintenance rate, superior to lansoprazole 15 mg (62 %). 1
• Second‑line escalation: Vonoprazan 20 mg daily should be considered only after documented failure of twice‑daily PPI therapy in patients with LA grade B or greater erosive esophagitis, Barrett’s esophagus, peptic stricture, or ambulatory pH monitoring showing distal esophageal acid exposure > 6 %. 1

2. H. pylori Eradication Regimens

• Standard triple therapy: Vonoprazan 20 mg twice daily + clarithromycin + amoxicillin for 14 days achieves a 92 % eradication rate, markedly higher than the 80 % rate with conventional PPI‑based triple therapy. 1
• Dual therapy (clarithromycin‑resistant strains): Vonoprazan 20 mg + amoxicillin 750 mg twice daily for 7 days yields 85‑95 % eradication, offering an effective alternative when clarithromycin resistance is present. 1
• Guideline recommendation: The 2024 AGA guideline endorses vonoprazan‑based regimens as first‑line therapy for all patients requiring H. pylori eradication. 1
• Comparative efficacy: Vonoprazan‑based regimens provide a 10‑20 % absolute increase in eradication rates versus high‑dose PPI‑based regimens, especially in clarithromycin‑resistant infections (≈ 66‑70 % vs ≈ 32 %). 1

3. Clinical Positioning

3.1 First‑Line Use

• H. pylori: Recommended as first‑line therapy per AGA guidelines because of superior acid suppression and higher eradication success. 1

3.2 Second‑Line Use (GERD / Peptic Ulcer Disease)

• Failure of twice‑daily PPI: Reserve vonoprazan for patients who have not responded to twice‑daily PPI therapy; the guideline notes higher cost without clear superiority in mild‑moderate disease. 1
• Standard initial therapy: Begin with standard‑dose PPI for LA grade A/B erosive esophagitis or non‑erosive GERD. 1

3.3 Situations of Particular Benefit

• Severe erosive esophagitis (LA C/D): Vonoprazan demonstrates superior maintenance of healing (75‑77 % vs 62 %) and lower recurrence rates (5‑13 % vs 39 %) compared with lansoprazole. 1

4. Metabolic Considerations

• CYP2C19 independence: Vonoprazan is not metabolized by CYP2C19, resulting in consistent therapeutic effects across all genetic phenotypes, unlike PPIs whose efficacy varies with CYP2C19 polymorphisms. 4
• Elimination of inter‑individual PK variability: The lack of CYP2C19 metabolism removes the pharmacokinetic variability seen with PPIs. 4

5. Alternative Acid‑Suppressive Therapies

• Standard‑dose PPIs: Lansoprazole 30 mg, omeprazole 20 mg, esomeprazole 20 mg, or rabeprazole 20 mg once daily remain first‑line for most acid‑related disorders due to established efficacy, extensive safety data, and lower cost. 1
• Double‑dose PPIs before vonoprazan: For PPI‑resistant GERD, a double‑dose PPI regimen (e.g., lansoprazole 30 mg twice daily) should be tried prior to switching to vonoprazan. 1
• High‑dose PPI‑based H. pylori therapy: When vonoprazan is unavailable, high‑dose PPI‑based triple or quadruple regimens are acceptable but achieve 10‑20 % lower eradication rates, especially against resistant strains. [4][1]
• CYP2C19‑guided PPI dosing: In populations with a high prevalence of CYP2C19 poor metabolizers, PPI dosing may need adjustment to achieve adequate acid suppression. 4

6. Evidence Requirements for Escalation to Vonoprazan

• Objective confirmation: Prior to escalating from twice‑daily PPI to vonoprazan, obtain endoscopic evidence of LA grade B or greater erosive esophagitis, or ambulatory pH monitoring demonstrating distal esophageal acid exposure > 6 %. 1

All bullet points are supported by the cited references and reflect the strength of evidence as presented in the source guidelines (e.g., AGA guideline recommendation).