Sodium Phosphate Enema
Sodium phosphate enemas are **osmotic laxatives** used to initiate rapid emptying of the colon in dogs. > **CRITICAL WARNING:** Strictly contraindicated in cats and small dogs (< 5 kg) due to the high risk of fatal electrolyte abnormalities (severe hyperphosphatemia and hypocalcemia).
Mechanism: Acts as a hyperosmotic agent in the rectum and colon. - Draws water into the colonic lumen via osmosis → increases intraluminal volume and pressure → stimulates **mechanoreceptors** → induces peristalsis and rapid bowel evacuation.
Dosing by species
- Cathartic / rapid emptying of the colon · 60-128 ml · Rectal · Single dose · As needed · For dogs 5-10 kg. Do not use in dogs < 5 kg.
- Cathartic / rapid emptying of the colon · 128 ml · Rectal · Single dose · As needed · For dogs > 10 kg.
- Contraindicated · DO NOT USE · Rectal · N/A · N/A · Fatal electrolyte abnormalities (hypocalcaemia and hyperphosphataemia) can occur.
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Routes of administration
Contraindications
- Cats (strictly contraindicated)
- Small dogs (< 5 kg)
- Dehydrated patients
- Patients with severe renal impairment
- Patients with compromised colonic mucosal integrity
Adverse effects
- Hyperphosphatemia
- Hypocalcemia
- Hypernatremia
- Dehydration
- Fatal electrolyte imbalances in sensitive species
Monitoring
- Serum calcium
- Serum phosphorus
- Serum sodium
- Hydration status
- ECG (if hypocalcemia is suspected)
Overdose
Overdosage or administration to contraindicated species (cats, small dogs) leads to severe **hyperphosphatemia**, **hypocalcemia**, and **hypernatremia**. Clinical signs include weakness, tremors, tetany, seizures, cardiac arrhythmias, shock, and death. **Treatment:** Aggressive IV fluid therapy (e.g., 0.9% NaCl) to correct dehydration and hypernatremia, and IV calcium gluconate to treat life-threatening hypocalcemia. Monitor electrolytes closely.
VetSheet drug reference is intended for licensed veterinary professionals as a clinical decision-support aid, not a substitute for professional judgement or the manufacturer’s current label.