Symptoms in the Pharmacy :Gastrointestinal Tract Problems(12)

Constipation Treatment

Treatment timescale

If 1 week’s use of treatment does not produce relief of symptoms, the
patient should see the doctor. If the pharmacist feels that it is only
necessary to give dietary advice, then it would be reasonable to leave it
for about 2 weeks to see if the symptoms settle.


Management
Constipation that is not caused by serious pathology will usually
respond to simple measures, which can be recommended by the
pharmacist: increasing the amount of dietary fibre; maintaining fluid
consumption; and taking regular exercise. In the short term, a laxative
may be recommended to ease the immediate problem.

Stimulant laxatives (e.g. senna, bisacodyl)

 
Stimulant laxatives work by increasing peristalsis. All stimulant laxatives
can produce griping/cramping pains. It is advisable to start at the
lower end of the recommended dosage range, increasing the dose if
needed. The intensity of the laxative effect is related to the dose taken.
Stimulant laxatives work within 6–12 h when taken orally. They
should be used for a maximum of 1 week. Bisacodyl tablets are
enteric-coated and should be swallowed whole because bisacodyl is
irritant to the stomach. If it is given as a suppository, the effect usually
occurs within 1 hour and sometimes as soon as 15 min after insertion.
Docusate sodium appears to have both stimulant and stoolsoftening
effects and acts within 12 days.

The use of senna pods and cascara, which is non-standardised,
should be discouraged because the dose, and therefore action, are
unpredictable. Castor oil is a traditional remedy for constipation,
which is no longer recommended since there are better preparations
available.

 Drugs that may cause constipation

• Analgesics and opiates   Dihydrocodeine, codeine
• Antacids   Aluminium salts
• Anticholinergics   Hyoscine
• Anticonvulsants    Phenytoin
• Antidepressants    Tricyclics, SSRIs
• Antihistamines    Chlorpheniramine, promethazine
• Antihypertensives    Clonidine, methyldopa
• Anti-Parkinson agents    Levodopa
• Beta-blockers    Propranolol
• Diuretics    Bendrofluazide
• Irono
• Laxative abuse
• Monoamine oxidase inhibitors
• Antipsychotics       Chlorpromazine

Bulk laxatives (e.g. ispaghula, methylcellulose, sterculia)

Bulk laxatives are those that most closely copy the normal physiological
mechanisms involved in bowel evacuation and are considered
by many to be the laxatives of choice. Such agents are especially useful
where patients cannot or will not increase their intake of dietary fibre.
Bulk laxatives work by swelling in the gut and increasing faecal mass
so that peristalsis is stimulated. The laxative effect can take several
days to develop.

The sodium content of bulk laxatives (as sodium bicarbonate)
should be considered in those requiring a restricted sodium intake.
When recommending the use of a bulk laxative, the pharmacist
should advise that an increase in fluid intake would be necessary. In
the form of granules or powder, the preparation should be mixed with
a full glass of liquid (e.g. fruit juice or water) before taking. Fruit juice
can mask the bland taste of the preparation. Intestinal obstruction
may result from inadequate fluid intake in patients taking bulk laxatives,
particularly those whose gut is not functioning properly as a
result of abuse of stimulant laxatives.

Osmotic laxatives (e.g. lactulose, Epsom salts, Glauber’s salts)

Lactulose works by maintaining the volume of fluid in the bowel. It
may take 1–2 days to work. Lactitol is chemically related to lactulose
and is available as sachets. The contents of the sachet are sprinkled on
food or taken with liquid. One or two glasses of fluid should be taken
with the daily dose. Lactulose and lactitol can cause flatulence,
cramps and abdominal discomfort.

Epsom salts (magnesium sulphate) is a traditional remedy that,
while no longer recommended, is still requested by some older customers.
It acts by drawing water into the gut; the increased pressure
results in increased intestinal motility. A dose usually produces a
bowel movement within a few hours. Repeated use can lead to dehydration.
Glycerin suppositories have both osmotic and irritant effects and
usually act within 1 h. They may cause rectal discomfort. Moistening
the suppository before use will make insertion easier.

Lubricant laxatives (e.g. liquid paraffin)

Liquid paraffin works by coating and softening the faeces; it prevents
further absorption of water in the colon. Long-term use can result in
impaired absorption of fat-soluble vitamins (A, D, E, K). Leakage of
liquid paraffin through the anal sphincter may occur, causing embarrassment
and unpleasantness. If liquid paraffin is inadvertently inhaled
into the lungs, lipid pneumonia can develop. Inhalation could
occur during vomiting or if acid reflux (regurgitation) is present. The
unpleasant and dangerous effects of liquid paraffin have led to restrictions
in the UK on the pack size that can be sold. Pharmacists have an
important role in discouraging the use of liquid paraffin, which has
little valid therapeutic use.

Constipation in children
Parents sometimes ask for laxatives for their children. Fixed ideas
about regular bowel habits are often responsible for such requests.
Numerous factors can cause constipation in children, including a
change in diet and emotional causes. Simple advice about sufficient
dietary fibre may be all that is needed. If the problem is of recent
origin and there are no significant associated signs, a single glycerin
suppository together with dietary advice may be appropriate. Referral
to the doctor would be best if these measures are unsuccessful.

Constipation in pregnancy
Constipation commonly occurs during pregnancy; hormonal changes
are responsible and it has been estimated that one in three pregnant
women suffers from constipation. Dietary advice concerning the
intake of plenty of high-fibre foods and fluids can help. Oral iron,
often prescribed for pregnant women, may contribute to the problem.
Stimulant laxatives are best avoided during pregnancy; bulkforming
laxatives are preferable, although they may cause some abdominal
discomfort to women when used late in pregnancy (see
‘Women’s Health’).

Constipation in the elderly
Constipation is a common problem in elderly patients for several
reasons. Elderly patients are less likely to be physically active; they
often have poor natural teeth or false teeth and so may avoid highfibre
foods that are more difficult to chew; multidrug regimens are
more likely in elderly patients, who may therefore suffer from druginduced
constipation; fixed ideas about what constitutes a normal
bowel habit are common in older patients. If a bulk laxative is to be
recommended for an elderly patient, it is of great importance that the
pharmacist give advice about maintaining fluid intake to prevent the
possible development of intestinal obstruction.

Laxative abuse
Two groups of patients are likely to abuse laxatives: those with
chronic constipation who get into a vicious circle by using stimulant
laxatives , which eventually results in damage to the nerve
plexus in the colon; and those who take laxatives in the belief that they
will control weight, e.g. those who are dieting or, more seriously,
women with eating disorders (anorexia nervosa or bulimia), who
take very large quantities of laxatives. The pharmacist is in a position
to monitor purchases of laxative products and counsel patients as
appropriate. Any patient who is ingesting large amounts of laxative
agents should be referred to the doctor.