Selecting a Treatment Regimen
Table 1. Some Commonly Used Laxative Preparations
Product
(Brand)
Starting
Dosage*
Onset
Time
Side Effects
Comments
• 12 h4 days
• Flatulence
• Bloating
• Intestinal blockage
• Swallowing
difficulty and
choking if not
taken with
adequate fluid, or
with dehydration†
• Must be taken with
8 oz of fluid
• Requires total fluid
intake of
≥ 64 oz/day
• Not appropriate for
patients with impaired
peristalsis (eg, OBD)
• 6-8 h
• Anal incontinence
• Anal irritation
• Oil leakage from
anus
• Prolonged use decreases
absorption of vitamins A,
D, E, and K
• Avoid in patients with
aspiration risk (lipid
pneumonitis)
• Separate from other
medications by 2 h
• Contraindicated in
pregnancy
• Bleeding risk in newborns
• Rectal irritation
• Abdominal
cramping
• Excessive diuresis
• Nausea and
vomiting
• Dehydration
• Systemic absorption
• Electrolyte imbalance
• Avoid in dehydration,
renal insufficiency,
congestive heart failure,
or cirrhosis
Bulk-Forming Laxatives
Metamucil®,
FiberChoice®,
Phillips'
FiberCaps®
• Varying
doses per
product
labeling
Lubricant Laxatives
Fleet Mineral
Oil®
• 15-45 mL
rectally at
bedtime
Osmotic Laxatives
Saline —
Magnesium
hydroxide
• 15-40 mL
PO
• 30 min-3 h
Sodium
phosphate
Fleet Enema®
• 118 mL
rectally
• 15-30 min
Sugars,
alcohols —
Lactulose,
sorbitol
• 15-60 mL
• 24-48 h
• Bloating
• Cramping
• Flatulence
• Diarrhea
• Nausea and
vomiting
• Epigastric pain
• Electrolyte imbalance
• Excessive gas
• More nausea and
vomiting with lactulose
• May be given as a
retention enema
Macrogols —
Polyethylene
glycol
MiraLAX®
• 17 g daily
dissolved
in 4-8 oz
liquid, for a
maximum of
7 days
• 1-3 days
• Loose, watery,
more frequent
stools
• Discontinue use and
contact physician if
rectal bleeding, diarrhea
or worsened nausea,
bloating, cramping, or
abdominal pain occurs
Continued
