Sodium phosphate enema

Osmotic Enema·Gastrointestinal - Laxatives

Relief of severe acute constipation, bowel clearance prior to sigmoidoscopy

ENEMAFleet EnemaPre-packaged rectal liquid (…UNSCHEDULEDTGA

Max Dose

1 Enema/day

Onset

2-5 mins

Phos. Toxicity

HIGH RISK

Renal Risk

MANDATORY

Rapid Summary

Overview

Highly concentrated hyperosmotic saline enema. Extremely effective for rapid distal bowel clearance, but carries significant risk of severe electrolyte derangement.

Maximum Dose

Max 1 Enema/day (Typically a single STAT dose).

Clinical Focus

Can cause fatal hyperphosphatemia and acute phosphate nephropathy in the elderly or those with renal failure.

Bottom Line

Sodium phosphate enema is a rapid-acting rectal enema for acute constipation and bowel preparation, but carries serious risk of phosphate toxicity especially in elderly and renally impaired patients.

Formulation & Access

Brand Names

Fleet Enema

Parenteral

Pre-packaged rectal liquid (133 mL). Contains dibasic and monobasic sodium phosphate.

Prescribing & PBS

Over The Counter (OTC).

Indications & Use

Primary

TGA

Relief of severe acute constipation, bowel clearance prior to sigmoidoscopy.

Clinical Place

Used on the ward only when oral agents and simple suppositories have failed.

Quick reference

Class & Role

Osmotic Enema — Highly concentrated hyperosmotic saline enema.

Route / Formulation

Pre-packaged rectal liquid (133 mL). Contains dibasic and monobasic sodium phosphate. (Fleet Enema)

Usual Dose & Max

PR 133 mL (1 adult enema) inserted rectally. Retain for 2-5 mins. Max 1 Enema/day (Typically a single STAT dose).

Key Indication Doses

Acute Faecal Impaction: PR 133 mL (1 adult enema) inserted rectally. Retain for 2-5 mins. Renal Impairment: Avoid entirely if eGFR < 45. Use a Microlax (citrate/lauryl sulfoacetate) enema instead.

Best Uses

Sodium phosphate enema is a rapid-acting rectal enema for acute constipation and bowel preparation, but carries serious risk of phosphate toxicity especially in elderly and renally impaired patients.

Avoid / Cautions

Renal impairment, congestive heart failure, ascites, megacolon, gastrointestinal obstruction.

Key Risks

Electrolytes: Hyperphosphatemia, profound hypocalcemia (precipitates tetany/arrhythmias), hypernatremia. Renal: Acute Phosphate Nephropathy (calcium-phosphate crystals precipitate in the kidneys, causing permanent irreversible renal failure). Gastrointestinal: Rectal trauma, mucosal sloughing.

Key Interactions

ACEi, ARBs, NSAIDs, Diuretics. These drugs reduce renal perfusion. Combining them with a Fleet enema guarantees acute kidney injury.

Monitoring

Check U&E and eGFR before prescribing. If the enema is given and the patient retains it (does not poop), you must check serum phosphate and calcium immediately. Ensure rapid access to a toilet. Do not give to immobile patients without a bedpan ready.

Clinical Pearl

If a Fleet enema goes in and nothing comes out, it is a medical emergency. The hyperosmotic fluid is sitting in the colon absorbing massive amounts of phosphate into the blood. You must manually disimpact or run a tap-water washout to get it out.

Access

Fleet Enema

Brand: Fleet Enema

Sodium phosphate enema

Osmotic Enema·Gastrointestinal - Laxatives

Relief of severe acute constipation, bowel clearance prior to sigmoidoscopy

ENEMAFleet EnemaPre-packaged rectal liquid (…UNSCHEDULEDTGA

Max Dose

1 Enema/day

Onset

2-5 mins

Phos. Toxicity

HIGH RISK

Renal Risk

MANDATORY

Rapid Summary

Overview

Highly concentrated hyperosmotic saline enema. Extremely effective for rapid distal bowel clearance, but carries significant risk of severe electrolyte derangement.

Maximum Dose

Max 1 Enema/day (Typically a single STAT dose).

Clinical Focus

Can cause fatal hyperphosphatemia and acute phosphate nephropathy in the elderly or those with renal failure.

Bottom Line

Sodium phosphate enema is a rapid-acting rectal enema for acute constipation and bowel preparation, but carries serious risk of phosphate toxicity especially in elderly and renally impaired patients.

Formulation & Access

Brand Names

Fleet Enema

Parenteral

Pre-packaged rectal liquid (133 mL). Contains dibasic and monobasic sodium phosphate.

Prescribing & PBS

Over The Counter (OTC).

Indications & Use

Primary

TGA

Relief of severe acute constipation, bowel clearance prior to sigmoidoscopy.

Clinical Place

Used on the ward only when oral agents and simple suppositories have failed.

Quick reference

Class & Role

Osmotic Enema — Highly concentrated hyperosmotic saline enema.

Route / Formulation

Pre-packaged rectal liquid (133 mL). Contains dibasic and monobasic sodium phosphate. (Fleet Enema)

Usual Dose & Max

PR 133 mL (1 adult enema) inserted rectally. Retain for 2-5 mins. Max 1 Enema/day (Typically a single STAT dose).

Key Indication Doses

Acute Faecal Impaction: PR 133 mL (1 adult enema) inserted rectally. Retain for 2-5 mins. Renal Impairment: Avoid entirely if eGFR < 45. Use a Microlax (citrate/lauryl sulfoacetate) enema instead.

Best Uses

Sodium phosphate enema is a rapid-acting rectal enema for acute constipation and bowel preparation, but carries serious risk of phosphate toxicity especially in elderly and renally impaired patients.

Avoid / Cautions

Renal impairment, congestive heart failure, ascites, megacolon, gastrointestinal obstruction.

Key Risks

Key Interactions

ACEi, ARBs, NSAIDs, Diuretics. These drugs reduce renal perfusion. Combining them with a Fleet enema guarantees acute kidney injury.

Monitoring

Clinical Pearl

Access

Fleet Enema

Brand: Fleet Enema