Source: Powell PH and Fleming
VH. Diarrhea, Constipation, and Irritable Bowel Syndrome. In: DiPiro, JT,
Talbert RL, Yee GC, Matzke GR, Wells BG, Posey LM. Pharmacotherapy:
A Pathophysiologic Approach. 8th ed. http://accesspharmacy.com/content.aspx?aid=7978775.
Accessed April 29, 2012.
- Functional constipation is bowel disorder characterized
by difficult, infrequent, or seemingly incomplete defecation that
does not meet criteria for irritable bowel syndrome (IBS).1
- Constipation may be primary (occurs without underlying
identifiable cause) or secondary (result of constipating
drugs, lifestyle factors, or medical disorders).
- Constipation is not a disease but symptom of underlying
disease or problem.
- Drugs that inhibit neurologic or muscular function of gastrointestinal
(GI) tract, particularly colon, may result in constipation (Table 1).
- All opiate derivatives associated with constipation
to varying degrees.
- Orally administered opiates appear to have greater inhibitory
effect than parenterally administered agents.
Table 1. Drugs Causing
Constipation |Favorite Table|Download (.pdf)
Table 1. Drugs Causing
Inhibitors of prostaglandin synthesis
Antiparkinsonian agents (e.g., benztropine or trihexyphenidyl)
Antacids containing calcium carbonate or aluminum hydroxide
Calcium channel blockers
Muscle blockers (d-tubocurarine,
Nonsteroidal antiinflammatory agents
Polystyrene sodium sulfonate
- Prevalence in North America ranges from 12-19%.
- More common in women and the elderly.
- Increase dietary fiber
- Initiate agents to soften stool when opiates are started.
- Increase activity level.
- Lack of activity
- Lower socioeconomic status
- Infrequent bowel movements
- Stools that are hard, small, or dry
- Difficulty or pain on defecation
- Feeling of abdominal discomfort
- Incomplete evacuation
Means of Confirmation
- History and physical examination to clarify what patient
means by constipation. Ask specifically about alarm signs and symptoms:
- Family history of colon cancer
- Family history of inflammatory bowel disease
- Weight loss
- Persistent constipation refractory to treatment
- New onset or worsening constipation in elderly patients without
evidence of primary cause
- Rectal examination should be performed for presence of anatomical
abnormalities, stricture, rectal mass, or fecal impaction.
- Identify underlying secondary causes or conditions.
- No routine lab tests recommended.
- Thyroid function studies, electrolytes, and blood glucose
to determine presence of metabolic or endocrine disorders.
- If alarm signs and symptoms present or when structural disease
a possibility, select appropriate diagnostic studies:
- Barium enema
- Relieve symptoms and restore normal bowel function.
- Prevention of further episodes through alteration of lifestyle,
- General measures believed to be beneficial in managing
- Dietary modification to increase
amount of fiber consumed daily