© 2003-17 Susan K. Mikota DVM and Donald C. Plumb, Pharm.D. Published by
Elephant Care International
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Chemistry – An acid-forming salt, ammonium chloride occurs as colorless crystals or as white, fine or course, crystalline powder. It is somewhat hygroscopic, and has a cool, saline taste. When dissolved in water, the temperature of the solution is decreased. One gram is soluble in approximately 3 ml of water at room temperature; 1.4 ml at 100°C. One gram is soluble in approximately 100 ml of alcohol.
One gram of ammonium chloride contains 18.7 mEq of ammonium and chloride ions. The commercially available concentrate for injection (26.75%) contains 5 mEq of each ion per ml and contains disodium edetate as a stabilizing agent. The pH of the concentrate for injection is approximately 5. Synonyms for ammonium chloride include muriate of ammonia and sal ammoniac.
Storage/Stability/Compatibility – Ammonium chloride for injection should be stored at room temperature; avoid freezing. At low temperatures, crystallization may occur; it may be resolubolized by warming to room temperature in a water bath.
Ammonium chloride should not be titrated with strong oxidizing agents (e.g., potassium chlorate) as explosive compounds may result.
Ammonium chloride is reported to be physically compatible with all commonly used IV replacement fluids and potassium chloride.
It is incompatible with: codeine phosphate, dimenhydrinate, methadone HCl, nitrofurantoin sodium, sulfisoxazole diolamine, and warfarin sodium. It is also reportedly incompatible with alkalis and their hydroxides.
Pharmacology – The acidification properties of ammonium chloride are caused by its dissociation into chloride and ammonium ions in vivo. The ammonium cation is converted by the liver to urea with the release of a hydrogen ion. This ion combines with bicarbonate to form water and carbon dioxide. In the extracellular fluid, chloride ions combine with fixed bases and decrease the alkaline reserves in the body. The net effects are decreased serum bicarbonate levels and a decrease in blood and urine pH.
The excess chloride ions presented to the kidney, are not completely reabsorbed by the tubules and are excreted with cations (principally sodium) and water. This diuretic effect is usually compensated for by the kidneys after a few days of therapy.
Uses/Indications – The veterinary indications for ammonium chloride are as a urinary acidifying agent to help prevent and dissolve certain types of uroliths (e.g., struvite), to enhance renal excretion of some types of toxins (e.g., strontium) or drugs (e.g., quinidine), or to enhance the efficacy of certain antimicrobials (e.g., chlortetracycline, methenamine mandelate, nitrofurantoin, oxytetracycline, penicillin G or tetracycline) when treating urinary tract infections. Ammonium chloride has also been used intravenously for the rapid correction of metabolic alkalosis.
Pharmacokinetics – No information was located on the pharmacokinetics of this agent in veterinary species. In humans, ammonium chloride is rapidly absorbed from the GI.
Contraindications/Precautions – Ammonium chloride is contraindicated in patients with severe hepatic disease as ammonia may accumulate and cause toxicity. In general, ammonium chloride should not be administered to uremic patients as it may intensify the metabolic acidosis already existing in some of these patients. Ammonium chloride should not be used alone in patients with severe renal insufficiency and metabolic alkalosis secondary to vomiting hydrochloric acid as sodium depletion can occur. In these cases, sodium chloride repletion with or without ammonium chloride administration should be performed to correct both sodium and chloride deficits. Ammonium chloride is contraindicated in patients with urate calculi or respiratory acidosis and high total CO2 and buffer base. Ammonium chloride cannot alone correct hypochloremia with secondary metabolic alkalosis due to intracellular potassium chloride depletion. Potassium chloride must be administered to these patients.
Do not administer subcutaneously, rectally or intraperitoneally. Use ammonium chloride with caution in patients with pulmonary insufficiency or cardiac edema.
Adverse Effects/Warnings – Development of metabolic acidosis (sometimes severe) can occur unless adequate monitoring is performed. When used intravenously, pain at the injection site can develop; slow administration lessens this effect. Gastric irritation, nausea and vomiting can be associated with oral dosing of the drug.
Overdosage – Symptoms of overdosage may include: nausea, vomiting, excessive thirst, hyperventilation, bradycardias or other arrhythmias, and progressive CNS depression. Profound acidosis and hypokalemia may be noted on laboratory results.
Treatment should consist of correcting the acidosis by administering sodium bicarbonate or sodium acetate intravenously. Hypokalemia should be treated by using a suitable oral (if possible) potassium product. Intense acid-base and electrolyte monitoring should be performed on an ongoing basis until the patient is stable.
Drug Interactions – Urine acidification may increase the renal excretion of quinidine.
The aminoglycosides (e.g., gentamicin) and erythromycin are more effective in an alkaline medium; urine acidification may diminish these drugs effectiveness in treating bacterial urinary tract infections.
a) 4 – 15 grams PO (Swinyard 1975)
Monitoring Parameters –
1) Urine pH (Urine pH’s of ≤6.5 have been recommended as goals of therapy)
2) Blood pH if there are symptoms of toxicity or treating metabolic alkalosis
3) Serum electrolytes, if using chronically or if treating metabolic acidosis
4) Prior to IV use it is recommended that the carbon dioxide combining power of the patient’s serum be measured to insure that serious acidosis is prevented
Client Information – Contact veterinarian if animal exhibits signs of nausea, vomiting, excessive thirst, hyperventilation or progressive lethargy.
Dosage Forms/Preparations/FDA Approval Status/Withholding Times –
Veterinary-Approved Products: None, but ammonium chloride is available in combination with methionine in the commercially available products: MEq® (Vet-A-Mix) and Uroeze® (Daniels).
Ammonium Chloride Tablets 500 mg (enteric-coated & plain) Note: enteric-coated tablets may be excreted unchanged into the feces and are not recommended.
Ammonium Chloride Concentrate for Injection 26.75% (5 mEq/ml) in 20 ml (100 mEq) vials. Must be diluted before infusion.
Generically labeled (Abbott); (Rx).
Preparation of solution for IV administration: Dilute 1 or 2 vials (100 – 200 mEq) in either 500 or 1000 ml of sodium chloride 0.9% for Injection. Do not administer at a rate greater than 5 ml/min (human adult).
Ammonium Chloride Tablets: 357 mg (6.7 mEq/tablet) 50 & 500 tabs/bottle MEq-AC ® (Vet-A-Mix); 200 mg tablets in btls of 100 and 500 Uroeze-200® (Daniels) Approved for use in cats and dogs. (Rx)
Ammonium Chloride Granules:MEq-5AC® (Vet-A-Mix) Each teasponnsful (3.35 grams) contains 535 mg (10mEq) in 4 oz and 1 lb bottles; Uroeze® (Daniels) each 1/4 teaspoonsful contains 200 mg of ammonium chloride. Approved for cats and dogs (Rx)
Ammonium Chloride Tablets 500 mg, 486 mg (Enteric-Coated); (OTC)
Ammonium Chloride Concentrate for Injection 26.75% (5 mEq/ml) in 20 ml (100 mEq) vials. Must be diluted before infusion. Generically labeled (Abbott); (Rx).