Gastroenterology Book

http://www.fpnotebook.com/

Osmotic LaxativeAka: Osmotic Cathartic, Sorbitol, Fleets Enema, Fleet Enema, Phospho-Soda, Magnesium Hydroxide, Milk of Magnesia, Magnesium Citrate, Polyethylene glycol, PEG, Miralax

Advertisement

  1. See Also
    1. Laxative
    2. Constipation
    3. Functional Constipation
    4. Pediatric Constipation
  2. Mechanism
    1. Poorly absorbed, they act as hyperosmolar agents
    2. Stimulate colonic activity (via cholecystokinin)
  3. Complications
    1. Hypermagnesemia (in patients with Renal Failure)
    2. Hypocalcemia (phosphate overdose)
  4. Contraindications
    1. Renal Failure (except Lactulose and Sorbitol)
  5. Preparations
    1. Poorly-absorbed sugars (may be used in Renal Failure)
      1. Lactulose (Chronulac)
        1. Easier to administer to young children
        2. May cause abdominal cramping and flatus
        3. More expensive then sorbitol ($10-30 per 480 ml)
        4. Onset of action within 24-48 hours
        5. Dose
          1. Adults: 15-60 ml PO daily
          2. Child (10 mg/15 ml): 1-3 cc/kg/day divided qd-bid
      2. Lactitol
        1. As effective as Lactulose with less pain and flatus
        2. Pitzalis (1995) Pediatr Med Chir 17(3):223
      3. Sorbitol 70%
        1. Less expensive than Lactulose ($7 per 480 ml)
        2. Sweet taste
        3. Dosing
          1. Adult: 15-60 ml PO daily
          2. Child: 1-3 ml/kg/day divided twice daily
    2. Magnesium salt osmotic Laxatives
      1. Rapid onset (within 3 hours)
      2. Avoid longterm use due to electrolyte loss risk
      3. Milk of Magnesia (Magnesium Hydroxide)
        1. Cost: $3 per 360 ml
        2. Concentration: 400 mg/5 ml
          1. Adults: 15-60 ml PO qd prn
          2. Children: 1-3 cc/kg/day divided bid prn
        3. Concentration 800 mg/5 ml
          1. Children: 0.5 cc/kg/day divided bid prn
        4. Adverse effects
          1. May cause abdominal cramping in higher doses
      4. Magnesium Citrate (Citroma)
        1. Cost: $1.50 per 300 ml
        2. Dose
          1. Adult: 8 ounces PO daily prn
          2. Child: 4 ml/kg up to 200 ml PO daily prn
    3. Mineral Oil
      1. Child: 1-3 cc/kg/day divided daily to twice daily
      2. Contraindicated if aspiration risk
      3. Not recommended under age 18 months
      4. Give chilled in juice to maximize tolerability
      5. Coadminister multivitamin daily if used chronically
    4. Sodium salt osmotic Laxatives
      1. Phopho-Soda 2 tablespoons in 4 ounces water orally
      2. Fleets enema (sodium phosphate) 120 ml enema
      3. Alternative agent: Tap Water Enema
    5. Polyethylene glycol 3350 (PEG, Miralax)
      1. Similar to bowel prep solution (GoLytely, Colyte)
      2. Onset of action with 24-48 hours
      3. No salty taste
      4. More expensive then Sorbitol: $2/day
      5. Preparation
        1. Use PEG powder 17 grams (one capful)
        2. Dissolve in 240 ml (8 ounces) water or juice
      6. Dose:
        1. Adult: 17 grams (1 capful) daily
        2. Child
          1. Start 0.8-1 g/kg/day (15 ml/kg/day) divided bid
          2. Adjust dose for two soft painless stools per day
          3. Taper dose over time
      7. Efficacy
        1. Safe, well tolerated and effective
        2. More effective and better tolerated than Lactulose
      8. References
        1. Gremse (2002) Clin Pediatr 41:225
        2. Pashankar (2003) Arch Pediatr Adolesc Med 157:661
        3. Voskuijl (2004) Gut 53:1590
  6. Preparations: Not recommended
    1. Castor oil or Ricinoleic Acid (Purge)
      1. Avoid due to electrolyte disturbance
      2. Adult: 15-30 ml PO qhs
      3. Child: 5-15 ml PO qhs
    2. Soapsuds Enemas (never use)
      1. Risk of irritation or hemorrhagic colitis

Polyethylene Glycols (C0032483)

Definition (MSH)Polymers of ETHYLENE OXIDE and water and their ethers. They vary in consistency from liquid to solid, depending on the molecular weight, indicated by a number following the name. They are used as SURFACTANTS, dispersing agents, solvents, ointment and suppository bases, vehicles, and tablet excipients. Some specific groups are lauromagrogols, nonoxynols, octoxynols and poloxamers.
Definition (CSP)an addition polymer of ethylene oxide and water.
ConceptsOrganic Chemical (T109) , Pharmacologic Substance (T121) , Biomedical or Dental Material (T122)
EnglishMacrogol, Macrogols, PEG, POLYETHYLENE GLYCOL, POLYETHYLENE GLYCOL PREPARATION, Polyethylene glycol product, Polyethylene Glycols, Polyethylene Oxide, Polyethyleneoxide, POLYOXYETHYLENE, POLYOXYETHYLENE PREPARATION, Polyoxyethylenes
Spanishmacrogol, polietilenglicol
CreditsDerived from the NIH UMLS (Unified Medical Language System)


Sorbitol (C0037688)

Definition (MSH)A polyhydric alcohol with about half the sweetness of sucrose. Sorbitol occurs naturally and is also produced synthetically from glucose. It was formerly used as a diuretic and may still be used as a laxative and in irrigating solutions for some surgical procedures. It is also used in many manufacturing processes, as a pharmaceutical aid, and in several research applications.
Definition (CSP)six-carbon sugar alcohol with about half the sweetness of sucrose; occurs naturally and is also produced synthetically from glucose.
Definition (NCI)A sugar alcohol found in fruits and plants with diuretic, laxative and cathartic property. Unabsorbed sorbitol retains water in the large intestine through osmotic pressure thereby stimulating peristalsis of the intestine and exerting its diuretic, laxative and cathartic effect. In addition, sorbitol has one-third fewer calories and 60 % the sweetening activity of sucrose and is used as a sugar replacement in diabetes.
ConceptsCarbohydrate (T118) , Pharmacologic Substance (T121)
EnglishD glucitol, Glucitol, Sorbitol, Sorbitol agent, SORBITOL PREPARATION
Spanishpreparado de sorbitol, sorbitol
CreditsDerived from the NIH UMLS (Unified Medical Language System)


Miralax (C0876088)

ConceptsOrganic Chemical (T109) , Pharmacologic Substance (T121)
EnglishMiralax
CreditsDerived from the NIH UMLS (Unified Medical Language System)



Navigation Tree