Page 59 - Community pharmcy practice E-book 2025

01/11/2025, 22:08 Medication Errors & Constipation Management

Bulk-Forming Laxatives

Mechanism of action: Absorb water to soften the stool and increase bulk, which
stimulates peristalsis. The only laxatives not systemically absorbed (locally acting)
Onset of action: Slow (12-24 hr and up to 72 hr). Not for acute constipation
Examples & marketed products:

Natural: Dietary bran, guar gum, psyllium (plantago seed in cereals)
(Regumucil®), malt soup extract

Synthetic: Methyl cellulose, Polycarbophil (Evak® tablets) and (Evaculax®
capsules)

Adverse Effects & Important Patient Counseling
Contraindications
Given with a cup of water (to minimize
Abdominal cramping possible esophagus, small intestine
and colon obstruction)
Flatulence (gas, bloating due to
interaction with intestinal bacteria) Dose spacing with oral anticoagulant,
digitalis, salicylates, oral tetracycline
Esophageal obstruction, any bowel with calcium polycarbophil
obstruction
Good in elderly & pregnancy
Not taken in intestinal ulceration or
adhesions

Not for children <6 yrs

Not in chronic IBS

Emollient Laxatives (Stool Softeners)

Mechanism of action: Surfactants allowing absorption of water into the stool,
which makes the softened stool easier to pass.
Onset of action: Slow (12-72 hrs). Best for patients who must avoid straining to
pass hard stools as those who recently have a myocardial infarction or rectal
surgery
Examples & marketed products: Docusate sodium (AOT) (Minalax® tablets, with
bisacodyl), New products…Docusate only, Doc Ca

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