OMEPRAZOLE AND SODIUM BICARBONATE
Clinical safety rating
safeCan decrease the levels of many drugs by increasing urinary pH Can cause metabolic alkalosis and fluid overload.
Omeprazole is a proton pump inhibitor that suppresses gastric acid secretion by inhibiting the H+/K+ ATPase enzyme system at the secretory surface of gastric parietal cells. Sodium bicarbonate is an antacid that neutralizes gastric acid.
| Metabolism | Omeprazole is extensively metabolized in the liver by cytochrome P450 (CYP) enzymes, primarily CYP2C19 and CYP3A4, to inactive metabolites. Sodium bicarbonate is not metabolized; it dissociates into sodium and bicarbonate ions. |
| Excretion | Omeprazole is primarily metabolized by CYP2C19 and CYP3A4; metabolites are excreted renally (~77% as metabolites) and fecally (~20% as metabolites). Urinary excretion of unchanged omeprazole is negligible (<1%). Sodium bicarbonate is excreted renally as bicarbonate and carbon dioxide. |
| Half-life | Terminal elimination half-life of omeprazole is approximately 0.5-1 hour. However, the pharmacodynamic effect (gastric acid suppression) lasts longer due to accumulation in parietal cells. Half-life does not correlate with duration of acid suppression. |
| Protein binding | Omeprazole is 95% bound to plasma proteins, primarily albumin and alpha-1-acid glycoprotein. |
| Volume of Distribution | Apparent volume of distribution is approximately 0.3-0.5 L/kg, suggesting distribution into total body water. The active form accumulates in parietal cell canaliculi. |
| Bioavailability | Oral bioavailability is approximately 30-40% after a single dose, increasing to 60-70% with repeated administration due to decreased first-pass metabolism. Bioavailability is not affected by food but is enhanced by the sodium bicarbonate component, which protects omeprazole from acid degradation. |
| Onset of Action | Oral: Onset of acid suppression occurs within 1 hour of administration. Maximal effect on gastric pH is seen within 2-4 hours. |
| Duration of Action | Duration of acid suppression persists for up to 24 hours after a single dose, with a peak effect at 2-4 hours and sustained elevation of intragastric pH for the remainder of the day. Continuous daily dosing leads to progressive acid suppression. |
| Molecular Weight | 345.41 (omeprazole) + 84.01 (sodium bicarbonate) |
Omeprazole 20 mg plus sodium bicarbonate 1100 mg orally once daily before a meal; for gastroesophageal reflux disease, dose may be increased to 40 mg orally once daily for 4-8 weeks.
| Dosage form | FOR SUSPENSION |
| Renal impairment | No dosage adjustment required for mild to moderate renal impairment; for severe renal impairment (GFR <30 mL/min), use with caution and monitor for sodium overload. |
| Liver impairment | For mild hepatic impairment (Child-Pugh class A), no adjustment; for moderate to severe impairment (Child-Pugh class B or C), maximum dose is 20 mg omeprazole once daily due to reduced metabolism. |
| Pediatric use | Not established for omeprazole/sodium bicarbonate combination; for omeprazole alone, weight-based dosing: 10-15 mg once daily for weight 10-20 kg, 20 mg once daily for weight >20 kg. |
| Geriatric use | No specific dose adjustment; use lowest effective dose, monitor for electrolyte imbalance (sodium) and increased risk of Clostridium difficile infection. |
| 1st trimester | Safe; no increased risk of major malformations observed in epidemiologic studies. |
| 2nd trimester | Safe; avoid high doses due to potential metabolic alkalosis from sodium bicarbonate. |
| 3rd trimester | Safe but monitor for hypocalcemia and metabolic alkalosis if high doses used. |
Clinical note
Can decrease the levels of many drugs by increasing urinary pH Can cause metabolic alkalosis and fluid overload.
| FDA category | Animal |
| Placental transfer | Omeprazole crosses the placenta in humans; sodium bicarbonate also crosses but is rapidly cleared. |
| Breastfeeding | Omeprazole is excreted in milk in low amounts; sodium bicarbonate is also excreted. Consider risk of metabolic alkalosis in infant with prolonged use. |
| Lactation Rating | L2 - Safer |
| Teratogenic Risk | First trimester: No increased risk of major congenital malformations based on large cohort studies. Second and third trimesters: Limited data, but no evidence of fetal harm. Omeprazole is FDA Pregnancy Category C; sodium bicarbonate is not associated with teratogenicity. |
| Fetal Monitoring | No specific monitoring required beyond routine prenatal care. For chronic use, monitor maternal serum electrolytes (sodium, bicarbonate) due to sodium bicarbonate component, especially with high doses or renal impairment. |
| Fertility Effects | Animal studies with omeprazole showed no adverse effects on fertility. Sodium bicarbonate does not affect fertility. Human data are lacking but no known impact on fertility. |
■ FDA Black Box Warning
No FDA black box warning.
| Common Effects | hyperkalemia |
| Serious Effects |
Hypersensitivity to omeprazole or any componentConcomitant atazanavir or nelfinavir (omeprazole reduces their absorption)Severe renal impairment (uncompensated metabolic alkalosis risk with sodium bicarbonate)
| Precautions | Gastric malignancy: Short-term treatment does not preclude presence of gastric malignancy., Clostridioides difficile infection: May increase risk., Bone fracture: Long-term use may increase risk of osteoporosis-related fractures of the hip, wrist, or spine., Hypomagnesemia: May cause low serum magnesium with prolonged use., Cyanocobalamin (Vitamin B12) deficiency: Prolonged acid suppression may impair absorption., Acute interstitial nephritis: Has been observed., Cutaneous lupus erythematosus: May increase risk., Interaction with methotrexate: May increase methotrexate toxicity., Sodium content: Contains sodium bicarbonate; caution in patients on sodium-restricted diet., Metabolic alkalosis: High doses of bicarbonate may cause metabolic alkalosis. |
| Food/Dietary | Avoid taking with food or within 30 minutes of eating. High-fat meals may delay absorption. No specific food restrictions, but alcohol and spicy foods may exacerbate symptoms. |
| Clinical Pearls | Administer on an empty stomach 1 hour before a meal for maximal acid suppression. The sodium bicarbonate component provides rapid antacid effect and may cause belching or gastric distension. Avoid in patients with Bartter's syndrome, hypokalemia, or metabolic alkalosis. Monitor magnesium levels with prolonged use; hypomagnesemia can occur with PPIs. For patients unable to swallow capsules, the contents can be mixed with applesauce. |
| Patient Advice | Take this medication 1 hour before a meal, usually once daily. · Swallow the capsule whole; do not crush or chew. If you have trouble swallowing, open the capsule and mix the granules with a tablespoon of applesauce, then swallow immediately. · Do not take with other antacids unless directed by your doctor. · Inform your doctor if you experience severe diarrhea, muscle cramps, irregular heartbeat, or signs of low magnesium (seizures, dizziness, abnormal heart rhythm). · Long-term use may increase risk of bone fractures, vitamin B12 deficiency, and kidney problems. |
Loading safety data…