Nexium (Esomeprazole)

Esomeprazole (Nexium) is used to treat acid‑related disorders by reducing gastric acid secretion.

• Gastro‑oesophageal reflux disease (GERD): alleviates heartburn and promotes healing of the esophageal lining.
• Erosive esophagitis: facilitates mucosal repair and reduces further acid injury.
• Zollinger‑Ellison syndrome: controls excessive gastric acid production associated with gastrin‑secreting tumors.
• Helicobacter pylori eradication (in combination therapy): enhances the effectiveness of antibiotic regimens by maintaining a higher gastric pH.

• Esomeprazole is the S‑enantiomer of omeprazole and acts as a selective, irreversible inhibitor of the gastric H⁺/K⁺‑ATPase (proton pump) located on the secretory surface of parietal cells. By binding covalently to the enzyme’s cysteine residues, it blocks the final step of acid secretion, leading to prolonged elevation of gastric pH and reduction of both basal and stimulated acid output, and thereby improves symptom control in acid‑related conditions.

Common and serious adverse reactions have been reported with esomeprazole use.

Common Side Effects

• Headache: mild to moderate intensity.
• Diarrhea: loose stools that may resolve with continued therapy.
• Nausea: occasional feeling of queasiness.

Serious or Rare Side Effects

• Clostridioides difficile infection: severe colitis requiring medical attention.
• Acute interstitial nephritis: kidney inflammation presenting with rash and eosinophilia.
• Stevens‑Johnson syndrome/toxic epidermal necrolysis: life‑threatening skin reactions.

Before prescribing esomeprazole, clinicians should consider several precautionary measures.

• Assess renal function: dose adjustment may be needed in severe impairment.
• Review concomitant medications: potential interactions with drugs requiring gastric acidity.
• Monitor long‑term use: prolonged therapy can increase risk of bone fractures.
• Evaluate for hypomagnesemia: periodic electrolyte testing is advised.
• Pregnancy and lactation: use only if potential benefit outweighs risk, as data are limited.
• Store at ambient temperature: keep below 25 °C, retain in original packaging, protect from moisture.

Esomeprazole may affect the pharmacokinetics of several co‑administered medicines.

Major Interactions (Avoid)

• Ketoconazole, itraconazole: reduced absorption due to increased gastric pH.
• Atazanavir, nelfinavir: markedly decreased plasma concentrations, compromising antiviral efficacy.
• Clopidogrel: diminished activation leading to reduced antiplatelet effect.

Moderate Interactions (Monitor Closely)

• Warfarin: possible increase in INR, requiring closer monitoring.
• Digoxin: modest increase in serum levels, may need dose adjustment.
• Methotrexate (high dose): increased exposure, monitor for toxicity.