Page 62 - Community pharmcy practice E-book 2025

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

Bisacodyl: Pregnancy category B (OTC)

Senna (OTC) (contraindicated in third trimester)
Docusate sodium – low doses (OTC) (cat C)

Saline and Osmotic Laxatives

Mechanism of action: Create an osmotic gradient to pull water into the small and
large intestines. This increased volume results in distention of the intestinal lumen,
peristalsis and bowel motility, activity of cholecystokinin-pancreozymin, and the
secretion of fluids into the GIT.
Onset of action:

Rectal formulations (e.g., enemas and suppositories): 5-30 min
Oral preparations: 3-6 hr

Glycerin supp: 15-60 min
Lactulose: 1-3 days to act (POM)

Saline and Osmotic Laxatives (continued)

Examples & marketed products:
Epsom salt (Magnesium sulfate)
Glycerin (Glycerin® suppositories)…hyperOsmotic
Lactulose (lactulose®, Duphalac syrup)
Polyethylene glycol 3350 (Miralax®)..osmotic

Adverse Effects & prolonged basis (fluid retention from
Contraindications sodium absorption)
PEG 3350 not <17yrs
Products containing magnesium: Not
in severe kidney impairment 61

Patients with hypertension or CHF
shouldn't receive saline laxatives on a