AMMONIUM CHLORIDE
Clinical safety rating
cautionComprehensive clinical and safety monograph for AMMONIUM CHLORIDE (AMMONIUM CHLORIDE).
Ammonium chloride is an acidifying agent. It dissociates to ammonium and chloride ions. The ammonium ion is converted to urea in the liver, releasing hydrogen ions, which lower blood and urinary pH. It also increases chloride concentration, promoting excretion of bicarbonate and other bases.
| Metabolism | Ammonium chloride is metabolized in the liver via the urea cycle, where ammonium is converted to urea, consuming bicarbonate and generating hydrogen ions. |
| Excretion | Renal: >99% as ammonium ion (NH4+) and chloride (Cl-), with acid excretion via conversion of NH4+ to urea in liver; minimal biliary/fecal. |
| Half-life | Terminal elimination half-life is approximately 8-12 hours in normal renal function; prolonged in renal impairment (up to 30 hours) due to reliance on renal acid excretion. |
| Protein binding | <10% bound to plasma proteins (primarily albumin). |
| Volume of Distribution | Approximately 0.3-0.5 L/kg, distributing mainly in extracellular fluid; minimal intracellular penetration. |
| Bioavailability | Oral: 70-80% (subject to first-pass hepatic conversion of NH4+ to urea); intravenous: 100%. |
| Onset of Action | Oral: 1-2 hours for systemic acidifying effect; intravenous: within 30 minutes. |
| Duration of Action | Oral: 4-6 hours after a single dose; intravenous: 2-4 hours; duration depends on renal function and acid-base status. |
| Molecular Weight | 53.49 |
For metabolic alkalosis: 1-2 g orally 3-4 times daily; or 1 g (as 2 mmol/kg) intravenously over 4-6 hours, repeat as needed based on blood gas analysis.
| Dosage form | INJECTABLE |
| Renal impairment | Contraindicated in severe renal impairment (GFR <30 mL/min). For GFR 30-60 mL/min: reduce dose by 50% and monitor for acidosis. For GFR >60 mL/min: no adjustment necessary. |
| Liver impairment | No specific Child-Pugh dose adjustments; use with caution in severe hepatic impairment due to risk of encephalopathy. |
| Pediatric use | For metabolic alkalosis: 50-100 mg/kg orally every 6-8 hours, not to exceed 6 g/day. Intravenous: 2-3 mmol/kg over 4-6 hours, repeat based on blood pH. |
| Geriatric use | Start at low end of dosing range; monitor renal function and electrolytes closely due to age-related decline in GFR. |
| 1st trimester | Use only when clearly needed; may cause maternal acidosis or vomiting leading to electrolyte disturbances. Animal studies show no teratogenicity, but human data insufficient. |
| 2nd trimester | Consider risk-benefit; monitor maternal acid-base and electrolytes. |
| 3rd trimester | Avoid near term due to risk of maternal acidosis and potential fetal compromise. |
Clinical note
Comprehensive clinical and safety monograph for AMMONIUM CHLORIDE (AMMONIUM CHLORIDE).
| Placental transfer | Rapid bidirectional transfer; achieves fetal concentrations similar to maternal plasma. |
| Breastfeeding | Excreted in breast milk in low concentrations; unlikely to cause adverse effects in infants if maternal doses are within therapeutic range. Monitor infant for irritability or metabolic acidosis. |
| Lactation Rating | L3 (Moderately Safe) |
| Teratogenic Risk | Ammonium chloride is not associated with major human teratogenicity. However, due to its potential to induce metabolic acidosis, high doses may pose theoretical fetal risks, including fetal acidosis and altered fetal pH homeostasis, particularly in the second and third trimesters. No specific trimester-specific risks are well-documented. |
| Fetal Monitoring | Monitor maternal serum electrolytes, chloride levels, and acid-base status (blood pH, bicarbonate, anion gap) regularly during therapy. In pregnancy, additional monitoring of fetal well-being (e.g., nonstress test, biophysical profile) may be warranted if high doses or prolonged therapy is used. Monitor for signs of maternal acidosis (hyperventilation, fatigue, confusion). |
| Fertility Effects | No known adverse effects on fertility in animal studies or human data. However, any drug-induced metabolic disturbances (e.g., acidosis) could theoretically impact reproductive function. There are no specific fertility warnings for ammonium chloride. |
■ FDA Black Box Warning
None.
| Serious Effects |
Severe hepatic or renal failureMetabolic alkalosisHypersensitivity to ammonium chloride
| Precautions | May cause metabolic acidosis, hyperammonemia in hepatic impairment, and electrolyte disturbances. Use with caution in patients with renal or hepatic disease, pulmonary insufficiency, or cardiac edema. |
| Food/Dietary | Avoid excessive consumption of alkaline foods (e.g., dairy products, fruits) as they may counteract the acidifying effect. Maintain a consistent diet to avoid fluctuations in acid-base balance. |
| Clinical Pearls | Ammonium chloride is used as a systemic acidifying agent to treat metabolic alkalosis. Monitor serum electrolytes and acid-base status closely during therapy. Avoid in severe hepatic or renal impairment. Use with caution in patients with respiratory acidosis. |
| Patient Advice | Take this medication exactly as prescribed. Do not exceed the recommended dose. · Notify your doctor if you experience nausea, vomiting, confusion, or rapid breathing. · Avoid taking with antacids or alkalinizing agents as they may reduce effectiveness. · Stay hydrated unless otherwise directed by your physician. · Inform your healthcare provider of all medications you are taking, especially diuretics or corticosteroids. |
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