b. Lubricant Cathartics. Lubricant cathartics are usually ingested at bedtime.
The patient should not take a lubricant cathartic with meals, since this could interfere
with the absorption of food, vitamins, and minerals in the gastrointestinal tract.
Furthermore, patients should be warned not to take lubricant cathartics for long periods
because of the absorption problems (e.g., reduced absorption of vitamins) associated
with their use. Lubricant laxatives usually provide results within 12 hours after
ingestion. Lastly, patients taking lubricant cathartics should be cautioned to protect their
clothing, since some leakage might occur from the rectum.
Product: Mineral Oil (Nujol). The oral dosage of this product, one to
three tablespoonsful, is usually given at bedtime. Several strengths of
this product are available (emulsion-50%; jell-55%; and plain-100%).
c. Stimulant Cathartics. Side effects associated with stimulant cathartics
include belching, diarrhea, and cramping. Stimulant cathartics should be taken on an
empty stomach in order to produce faster effects. Potassium loss, cramping, the
laxative habit, and pinkish urine or stool are effects associated with stimulant cathartics.
(1) Bisacodyl (Dulcolax). Bisacodyl is available in tablet form (five
milligrams per tablet). The usual dose is two to three tablets. Only one dose of the
medication is taken. The tablets should be swallowed whole with a full glass of water (8
fluid ounces = 240 milliliters). The patient taking this product should be warned not to
chew or crush the tablet (the contents have a bitter taste). Furthermore, the patient
should be cautioned not to take this product within one hour after taking antacids or
milk, since these products may cause the enteric coating of the tablet to be prematurely
removed in the stomach and result in gastric irritation.
(2) Cascara (Cas-Evac). Cascara is available as the aromatic cascara
fluid extract and as cascara tablets. Persons receiving the fluid extract should be told to
thoroughly shake the container before taking the dose. Persons taking either product
should be told that cascara can discolor the urine.
(3) Castor oil (Alphamul, Neoloid). Castor oil is available in an emulsified
form as well as in an aromatic form. The usual adult dose of this product is from one to
(4) Danthron (Dorbane). This product is available in both tablet and
solution form. The solution dosage form contains five percent ethyl alcohol. Persons
taking this drug should be warned that their urine may become discolored because of
(5) Dehydrocholic acid (Decholin). This product is available in 250
milligram tablets. The usual adult dose of dehydrocholic acid is one tablet three or four
times a day. This product is not recommended for patients under 12 years of age.