ESOMEPRAZOLE MAGNESIUM
Clinical safety rating: safe
Animal studies have demonstrated safety
Esomeprazole is a proton pump inhibitor that suppresses gastric acid secretion by specific inhibition of the H+/K+ ATPase at the secretory surface of gastric parietal cells.
| Metabolism | Extensively metabolized in the liver primarily via CYP2C19 and CYP3A4. Metabolites are inactive. |
| Excretion | Approximately 80% of a dose is excreted as metabolites in urine, with the remainder (about 20%) eliminated in feces via biliary excretion. Less than 1% is excreted unchanged in urine. |
| Half-life | Terminal elimination half-life is approximately 1–1.5 hours in healthy individuals, but may be prolonged to 2–3 hours in poor metabolizers (CYP2C19) or patients with hepatic impairment. The effect on gastric acid secretion persists for 24 hours due to irreversible binding to proton pumps. |
| Protein binding | 97% bound to plasma proteins, primarily albumin. |
| Volume of Distribution | Vd is approximately 0.22–0.28 L/kg (15–20 L in a 70 kg adult), indicating distribution primarily in extracellular fluid and minimal tissue binding. |
| Bioavailability | Oral: 50–90% (mean ~64%) after a single dose, but increases to 89% with repeated once-daily dosing due to reduced first-pass metabolism. Bioavailability is decreased by food (take before meals). Intravenous: 100%. |
| Onset of Action | Oral: Onset of acid suppression occurs within 1 hour; maximal effect is achieved after 2–4 days of once-daily dosing. Intravenous: Onset of action within 30 minutes. |
| Duration of Action | Acid suppression persists for 24 hours after a single dose, allowing once-daily dosing. The duration of effect is longer than the plasma half-life due to accumulation in parietal cell canaliculi and irreversible proton pump inhibition. |
| Molecular Weight | 767.5 Da (as trihydrate; active moiety: esomeprazole 345.4 Da) |
20-40 mg orally once daily; for erosive esophagitis, 40 mg once daily for 4-8 weeks. IV: 20-40 mg once daily over 10-30 minutes.
| Dosage form | CAPSULE, DELAYED REL PELLETS |
| Renal impairment | No dose adjustment required for GFR >15 mL/min; for GFR <15 mL/min, no specific data, use with caution as no dose reduction needed. |
| Liver impairment | Child-Pugh A and B: No dose adjustment. Child-Pugh C: Maximum dose 20 mg daily. |
| Pediatric use | Weight <20 kg: 10 mg once daily; ≥20 kg: 20 mg once daily; for erosive esophagitis, 20 mg once daily (weight <20 kg) or 40 mg once daily (weight ≥20 kg) for 4-8 weeks. |
| Geriatric use | No routine dose adjustment; monitor for hypomagnesemia and increased risk of fractures with long-term use; consider lower starting dose (20 mg) in frail elderly. |
| 1st trimester | No evidence of increased risk of major congenital malformations. Minor anomalies reported but not consistently attributed. |
| 2nd trimester | No evidence of fetal harm in human studies; use only if clearly needed. |
| 3rd trimester | No evidence of fetal harm; may be used if required. |
Clinical note
Can reduce absorption of drugs requiring gastric pH for absorption (eg ketoconazole) May increase risk of Clostridium difficile-associated diarrhea and bone fractures with long-term use.
| Placental transfer | Passes the placenta; fetal plasma concentrations are low. |
| Breastfeeding | Excretion into breast milk is low; expected to be compatible with breastfeeding. |
| Lactation Rating |
■ FDA Black Box Warning
No FDA black box warning.
| Common Effects | erosive esophagitis |
| Serious Effects |
Hypersensitivity to esomeprazole or substituted benzimidazolesConcomitant use with rilpivirineConcomitant use with nelfinavir
| Precautions | Long-term use (e.g., >1 year) may increase risk of osteoporosis-related fractures (hip, wrist, spine); hypomagnesemia can occur with prolonged use; gastric atrophy; atrophic gastritis; Clostridium difficile infection; vitamin B12 deficiency; acute interstitial nephritis; cutaneous and systemic lupus erythematosus; fundic gland polyps; interference with laboratory tests; potential for increased risk of acute myocardial infarction (observational data). |
| Food/Dietary | Esomeprazole should be taken on an empty stomach, at least 1 hour before food, to maximize absorption. High-fat meals may delay and reduce absorption. Avoid grapefruit juice as it may inhibit CYP3A4 and increase esomeprazole levels, though effect is minor. No specific food restrictions; however, heavy or spicy meals may aggravate underlying GERD symptoms. Concomitant intake of iron supplements, calcium carbonate, or multivitamins may be less effective due to reduced gastric acidity; separate administration by at least 2 hours is recommended. |
Loading safety data…
| L2 (Probably Compatible) |
| Teratogenic Risk | Esomeprazole magnesium, a proton pump inhibitor, is classified as FDA Pregnancy Category B. Available data from observational studies and postmarketing surveillance have not identified a drug-associated risk of major birth defects, miscarriage, or adverse maternal or fetal outcomes. However, studies are limited. First trimester exposure: No increased risk of congenital anomalies based on cohort studies. Second and third trimesters: No specific fetal risks documented. Nevertheless, decreased gastric acidity may reduce maternal absorption of iron and calcium, potentially affecting fetal iron stores and bone mineralization. Use only if clearly needed. |
| Fetal Monitoring | Monitor maternal hemoglobin and ferritin levels due to potential decreased iron absorption. Assess calcium and vitamin B12 levels with prolonged use. Fetal growth and development via standard prenatal ultrasound. Report any signs of maternal infection (e.g., pneumonia, C. difficile diarrhea) as PPIs may increase risk. No specific fetal monitoring required beyond routine prenatal care. |
| Fertility Effects | No evidence of impaired fertility in animal studies. In humans, no clinical data suggest significant effects on male or female fertility. Proton pump inhibitors may affect sperm parameters (e.g., motility) in some studies, but clinical relevance is unclear. Overall, esomeprazole is not associated with clinically relevant fertility impairment. |
| Clinical Pearls | Esomeprazole magnesium is the S-isomer of omeprazole, providing more consistent acid suppression than omeprazole. This drug is a prodrug that is activated in the acidic environment of gastric parietal cells. Avoid co-administration with clopidogrel due to potential reduction in clopidogrel efficacy via CYP2C19 inhibition. For IV use, dilute reconstituted solution appropriately and administer over 10-30 minutes. Long-term use beyond 1 year increases risk of osteoporosis-related fractures, vitamin B12 deficiency, and hypomagnesemia. Consider 'on-demand' or step-down therapy for GERD. In patients with CYP2C19 poor metabolizers (e.g., 3% of Caucasians, 15-20% of Asians), esomeprazole exposure is increased. Monitor for Clostridium difficile infection with prolonged use. |
| Patient Advice | Take this medication at least 1 hour before a meal, typically before breakfast. · Swallow capsules whole; do not crush or chew. If using oral suspension, mix with 15 mL of water and drink immediately. · Do not take with other acid reducers (e.g., antacids, H2 blockers) unless advised by your healthcare provider. · Inform your doctor if you develop severe diarrhea, weight loss, or bone pain. · If you are taking clopidogrel, discuss with your doctor before starting esomeprazole. · Avoid alcohol as it can worsen acid reflux symptoms. · Do not use for immediate relief of heartburn; it may take 1-4 days to take effect. |