Bulking agents (fiber)*

Bran

Bloating, passing of gas (flatulence), and poor absorption of iron and calcium

Bulking agents generally are used to prevent or control chronic constipation.

Polycarbophil

Bloating and flatulence

Less bloating than with other fiber agents

Bloating and flatulence

Stool softeners

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Stool softeners may be used to treat constipation and are often used to help prevent it.

Rectal irritation

Lung inflammation caused by fats in the lungs (lipid pneumonia), poor absorption of fat-soluble vitamins, dehydration, and loss of control over bowel movements (fecal incontinence)

Osmotic agents

Abdominal cramps and flatulence

Osmotic agents are better for treating constipation than for preventing it.

Too much magnesium in the body (magnesium toxicity), dehydration, abdominal cramps, and fecal incontinence

Fecal incontinence (related to dosage)

Sodium phosphate

Rare cases of sudden kidney failure

Abdominal cramps and flatulence

Stimulant laxatives

Abdominal cramps and dehydration

Stimulant laxatives are not used if there is a possibility of an intestinal obstruction.

Prolonged use can damage the large intestine.

Fecal incontinence, a low level of potassium in the blood (hypokalemia), abdominal cramps, and rectal burning with daily use of the suppository form

Abdominal cramps, flatulence

Not used in children

Nausea, particularly when the drug is taken on an empty stomach, and headache

Dizziness, urinary tract infection (not common)

Headache, abdominal pain, increased risk of depression and suicidal behavior

Enemas

Fecal incontinence

Although rare, giving an enema can injure the rectum if the procedure is done roughly.

Tap water

Fluid overload if a lot of water is absorbed

Phosphate

A high level of phosphate in the blood (hyperphosphatemia)

Soapsuds

Cramps