Ammonium Chloride
Ammonium chloride is an acidifying salt used orally to lower urinary pH in selected veterinary patients. Its role is most relevant when a urinary disorder benefits from acidification, including prevention of certain calculi in ruminants. Whether it helps depends on stone composition, diet and the patient’s acid-base status.
It does not act as a general urinary antiseptic and does not dissolve every type of urolith. Historical use for chronic urinary infection reflects modification of the urinary environment rather than direct elimination of the infecting organism.
Group
Urinary acidifier
Mechanism of Action
Ammonium chloride dissociates into ammonium and chloride ions. Hepatic metabolism of ammonium to urea consumes bicarbonate and imposes an acid load, reducing the body’s alkaline reserve. Renal handling of this load increases acid excretion and can lower urinary pH.
A more acidic urinary environment reduces the tendency of some phosphate-containing minerals to precipitate and can increase the solubility of susceptible calculi. The direction of benefit depends on mineral chemistry: acidification appropriate for one stone type can be inappropriate for another.
The resulting change in acid-base balance is systemic as well as urinary. Excessive exposure can therefore cause metabolic acidosis rather than merely producing a lower urine-pH reading. The desired urinary response also varies with the buffering and mineral content of the overall diet.
Dose Rates
Dogs
| Use / stage | Dose | Route | Schedule | Instructions |
|---|---|---|---|---|
| Urinary acidification | 100 mg/kg | PO | Every 12 h | |
| Struvite urolith adjunct | 20 mg/kg | PO | Every 8 h | |
| Enhanced renal elimination of selected toxicants | 50 mg/kg | PO | Every 6 h | Derived from 200 mg/kg/day divided into four equal amounts; select only toxicants for which acidification is appropriate. |
| Strontium elimination adjunct | 0.2–0.5 g/animal | PO | Every 6–8 h | Used with calcium salts. |
| Oral ammonia tolerance test | 100 mg/kg | PO | Once | Maximum 3000 mg/dose; Oral challenge in 20–50 mL warm water or gelatin capsules; sample at 30 and 60 minutes. A non-challenge fasting/postprandial alternative may avoid ammonium exposure. |
Cats
| Use / stage | Dose | Route | Schedule | Instructions |
|---|---|---|---|---|
| Urinary acidification – weight-based listing | 20 mg/kg | PO | Every 24 h | Mix with food. The separately listed 800 mg/cat amount is not equivalent and is withheld pending clarification. |
| Urinary acidification – fixed amount listing | 800 mg/animal | PO | Every 24 h | An unresolved alternative is 800 mg/cat alongside 20 mg/kg and a household-volume estimate. These are not equivalent; confirm intended amount before use. |
| Struvite urolith adjunct | 20 mg/kg | PO | Every 12 h | Use only when dietary and infection management do not adequately acidify urine; patient must not be obstructed. |
Horses
| Use / stage | Dose | Route | Schedule | Instructions |
|---|---|---|---|---|
| Urinary acidification | 100–250 mg/kg | PO | Every 24 h | |
| Urinary acidification – broader daily alternative | 60–520 mg/kg | PO | Every 24 h | Unpalatable; stomach tube or dosing syringe may be necessary. Diet composition affects response. |
| Urinary acidification – fixed alternative | 4–15 g/animal | PO | ||
| Strychnine elimination adjunct | 132 mg/kg | PO | No repeat interval specified. |
Cattle
| Use / stage | Dose | Route | Schedule | Instructions |
|---|---|---|---|---|
| Urolithiasis prevention | 200 mg/kg | PO | Repeat interval is not specified. | |
| Urolithiasis prevention – fixed alternative | 15–30 g/animal | PO |
Sheep
| Use / stage | Dose | Route | Schedule | Instructions |
|---|---|---|---|---|
| Urolithiasis prevention | 300 mg/kg | PO | Repeat interval is not specified. | |
| Urolithiasis prevention – dietary inclusion | Reference only | PO | 0.5–1% of daily dry matter; palatability can limit intake. Do not substitute this dietary percentage for mg/kg body weight. |
Goats
| Use / stage | Dose | Route | Schedule | Instructions |
|---|---|---|---|---|
| Urolithiasis prevention | 300 mg/kg | PO | Repeat interval is not specified. | |
| Urolithiasis prevention – dietary inclusion | Reference only | PO | 0.5–1% of daily dry matter; palatability can limit intake. Do not substitute this dietary percentage for mg/kg body weight. |
Indications
- Urinary acidification in selected calculous disorders where mineral composition and dietary assessment support it, including prevention of some phosphate-containing uroliths in small ruminants.
- Adjunctive management of selected bladder-calculus cases in which acidification forms part of a specific dissolution or prevention plan; it is not treatment for an established mechanical urinary obstruction.
- Historical adjunctive use in chronic urinary tract infection where a lower pH is desirable. It does not replace culture-directed antimicrobial treatment when bacterial infection requires treatment.
- Routine addition to an already acidifying feline urinary diet is not automatically beneficial and can create excessive acidification.
Contraindications
- Systemic acidemia.
- Use cautiously in renal disease.
- Severe hepatic disease, urate calculi or respiratory acidosis.
- Generally avoid in uremia; it may worsen existing metabolic acidosis.
- Do not give SC, IP or rectally for routine acidification.
- Use cautiously with pulmonary insufficiency or cardiac edema.
Interactions
- Urine acidification can reduce aminoglycoside or erythromycin activity in urinary infection and increase quinidine elimination.
Adverse effects
- Bitter taste and poor acceptance.
- High doses can cause acidemia.
- Gastric irritation, nausea and vomiting.
- Feline urinary acidification increases calcium-oxalate stone risk.
Toxicity
Overdose may cause vomiting, thirst, hyperventilation, arrhythmias and progressive CNS depression with severe acidosis or hypokalemia. Correct acid–base and electrolyte disturbances with close monitoring; IV bicarbonate or acetate and appropriate potassium replacement may be required.
Preparations
| Preparation | Form | Strength | Route |
|---|---|---|---|
| Ammonium chloride crystals | Powder | 1000 mg / g | PO |
| Ammonium chloride 200 mg tablet | Tablet | 200 mg / tablet | PO |
| Ammonium chloride 400 mg tablet | Tablet | 400 mg / tablet | PO |
Monitoring and Administration
Monitor acid–base status and urinary response. Mix with food only when intake remains adequate.
Store crystals tightly closed and protected from light at room temperature.
A historical rectal ammonia-tolerance challenge is 2 mL/kg of 5% solution with samples at 20 and 40 minutes, but routine rectal use is otherwise prohibited. This conflicting procedural route is not offered for calculation.
Monitor urinary pH, with a cited goal at or below 6.5 where acidification is indicated; check blood pH and electrolytes during prolonged treatment or suspected toxicity. An injectable concentrate contains 267.5 mg/mL (5 mEq/mL); no general veterinary IV infusion regimen is established here.