Amoxicillin/Vonoprazan Side Effects: What to Expect and When to Call Your Doctor

Amoxicillin/Vonoprazan (Voquezna Dual Pak) is a 14-day combination treatment for H. pylori infection. Like all antibiotics and acid-blocking medications, it can cause side effects. Most are mild and resolve on their own, but a few require prompt medical attention. Here's exactly what to expect.

Common Side Effects of Amoxicillin/Vonoprazan

The following side effects were reported in clinical trials and are considered common (occurring in 1–10% or more of patients). Most are manageable and don't require stopping treatment:

• Diarrhea — The most frequently reported side effect. Usually mild and resolves after finishing the course. Stay hydrated.
• Abdominal pain or cramping — Mild discomfort is common; if severe or worsening, call your doctor.
• Vulvovaginal candidiasis — Yeast infections are common with antibiotic use; over-the-counter antifungal treatments are effective.
• Nasopharyngitis — Upper respiratory symptoms, cold-like effects.
• Nausea — Taking the medication with food may reduce nausea.
• Headache — Generally mild. Acetaminophen (Tylenol) can help.

Serious Side Effects — Call Your Doctor Immediately

The following are rare but serious. Do not wait — seek medical attention immediately if you experience any of these:

• Signs of anaphylaxis or severe allergic reaction: hives, difficulty breathing, swelling of the face, lips, tongue, or throat. Call 911 immediately.
• Severe Cutaneous Adverse Reactions (SCAR): fever, sore throat, burning eyes, skin pain, blistering, peeling. Discontinue medication and seek emergency care.
• Clostridioides difficile-associated diarrhea (CDAD): Severe, watery, or bloody diarrhea that may occur during or up to 2 months after completing treatment. Do not treat with anti-diarrheal medications without calling your doctor first.
• Severe vomiting — Particularly if it occurs 1–4 hours after taking a dose. This may indicate a serious GI reaction.
• Acute interstitial nephritis: Blood in urine, burning when urinating, little or no urine output.
• Bone fracture symptoms: Sudden pain or trouble moving your hip, wrist, or spine. Vonoprazan (a PCAB) has been associated with increased fracture risk with long-term use, though the 14-day H. pylori course is considered short-term.

Who Is at Higher Risk for Side Effects?

Certain patients are at elevated risk for specific side effects:

• Patients with a history of mononucleosis ("mono"): Higher risk for amoxicillin-associated rash.
• Patients with kidney disease: Voquezna Dual Pak is not recommended for those with severe renal impairment (eGFR < 30 mL/min).
• Patients with liver disease: Not recommended in moderate-to-severe hepatic impairment (Child-Pugh Class B or C).
• Patients on proton pump inhibitors (PPIs): The labeling advises avoiding concomitant use of omeprazole with vonoprazan.

Tips to Reduce Side Effects During Treatment

• You can take Amoxicillin/Vonoprazan with or without food. If nausea is a problem, try taking doses with a light meal.
• Stay well hydrated, especially if you experience diarrhea.
• Consider adding a probiotic (e.g., Lactobacillus rhamnosus GG) to reduce antibiotic-associated diarrhea — discuss with your doctor first.
• Do not stop taking the medication early because you feel better. Completing the full 14-day course is essential to eradicate H. pylori and prevent resistance.

The Bottom Line

Most people who take Amoxicillin/Vonoprazan experience only mild, manageable side effects like diarrhea or mild stomach discomfort. Serious reactions — allergic responses, SCAR, C. difficile — are rare but require immediate attention. If you're unsure about any symptom during your treatment course, contact your prescriber. See also: Amoxicillin/Vonoprazan Drug Interactions.