II. Indications
- Functional Constipation
- Colonoscopy preparation
III. Contraindications
IV. Mechanism
- Poorly absorbed, hyperosmolar agents
- Increases intestinal retention of water, stimulating stool passage
- Also, increases renal excretion of Hydrogen Ion, in place of the reabsorption of Sodium ions
V. Complications
- Hypocalcemia (phosphate Overdose)
VI. Medications: Sodium Salt Osmotic Laxatives
- Phopho-Soda (OsmoPrep, Visicol) 2 tablespoons in 4 ounces water orally
- Fleets Enema (Sodium phosphate) 133 ml enema (adult) or 66 ml enema (pediatric)
- Pink Lady Enema (1/2 Fleet Enema, 100 ml Docusate, 60 ml Mineral Oil, 60 ml Magnesium Citrate)
- Alternative agents
- Tap Water Enema
VII. Dosing: Sodium Phosphate Enema
-
General
- Onset of action: 2 to 5 minutes
- Attempt to retain enema for 15 to 30 minutes before stooling
- Adults (and age >12 years)
- One adult enema (133 ml) per Rectum
- Sodium phosphate may be used orally up to 45 ml/24 hours
- Risk of serious Electrolyte abnormalities or Renal Failure with higher doses or recurrent use
- Children: 2.5 ml/kg (up to 133 ml/dose)
VIII. Dosing: OsmoPrep
- Indicated prior to Colonoscopy
- Dispense 32 OsmoPrep tabs (1.5 g/tab)
- Evening before procedure
- Take 4 tabs orally with 8 oz clear fluid every 15 min for total of 20 tabs (5 doses in 75 min, 40 oz fluid)
- Day of procedure (starting 3 to 5 hours before)
- Take 4 tabs orally with 8 oz clear fluid every 15 min for total of 12 tabs (3 doses in 45 min, 24 oz fluid)
IX. Technique: Protocol for those who cannot Retain Enema (e.g. Dementia, Traumatic Brain Injury)
- Place Foley Catheter inserted into Rectum and slowly inflated
- Infuse enema liquid into Foley Catheter using Toomey syringe
- Tilt head of bed down to 15 to 30 degrees (trendelenburg position)
- Leave the Foley Catheter and balloon in place for 15 to 20 minutes to allow adequate enema retention time
- Prepare for rapid outflow of stool contents (pads and other protection on bed)
- Deflate the balloon and remove the Foley Catheter (standing to side)
- Fisher and Swaminathan in Swadron (2022) EM:Rap 22(11): 7-8
X. Adverse Effects
- Acute phosphate nephropathy (FDA Black Box Warning)
- Risk of permanent impact on Renal Function following use
- Risk Factors
- Diabetes Mellitus
- Age over 65 years
- Dehydration
- Concurrent NSAID, ACE Inhibitor, ARB or Diuretic
- Prevention of Renal Function impact
- Consider alternative Bowel Preparation if risk factors above
- Maintain clear fluid intake to replace fluid losses from Diarrhea
- Rectal Wall Trauma
- Abdominal Pain
- Abdominal Distention
- Nausea
- Hyperphosphatemia
- Hypocalcemia
- Hypokalemia
XI. Safety
- Pregnancy Category C
- Unknown safety in Lactation (but not typically absorbed)
XII. Drug Interactions
- Agents that decrease renal perfusion
XIII. Resources
XIV. References
- (2023) Management of Constipation, Presc Lett, #390108
- Hamilton (2020) Tarascon Pocket Pharmacopoeia
Images: Related links to external sites (from Bing)
Related Studies
| fleet enema (on 9/12/2022 at Medicaid.Gov Survey of pharmacy drug pricing) | ||
| FLEET ENEMA | Generic OTC | $0.01 per ml |
| osmoprep (on 1/1/2022 at Medicaid.Gov Survey of pharmacy drug pricing) | ||
| OSMOPREP TABLET | $8.02 each | |