Page 154 Guide to Pain Management in Low-Resource Settings

142 Andreas Kopf

patients have found to be helpful in their personal expe- What are the mechanisms of action
cient, the second step of typical laxatives? ffirience. If these laxatives are insu
is to combine them with either senna or bisacodyl tab-
lets. Th ese tablets also should be taken at bedtime and Th e simplest mechanism is the “softening of stool,” which
cient to allow stool regulation in non-can- ffiincreased by one tablet daily until there are successful usually is su
bowel movements. Th e permanent dose would be the cer patients who have normal daily activities and a nor-
uid intake. Th e cheap and available polysac- flresult of careful up-and-down titration at the beginning mal daily
of laxative therapy. At step three, the laxatives have to charide lactulose is non-resorbable and attracts water
be combined with local therapy, either suppositories into the intraluminal space of the intestines. By increas-
with bisacodyl or glycerine. If suppositories are unavail- ing intraluminal volume and dilating the intestinal wall, a
ect is triggered. Unfortunately, fermentation ffable, custom-made petroleum jelly will do as well (a propulsive e
ect of lactulose, resulting in gas formation. fflump of it has to be held inside by the patient, preferably is a side e
cial polyethylene glycol macrogol has fifor about 20 minutes). Always try to avoid bedpans and Th e arti
ect but does not need as much ffective a similar osmotic e ffallow the patient to sit or squat to have more e
uid intake and therefore may be better suited for the flabdominal muscle contractions.
uid intake is flabdominal cancer patient, whose daily
ects and is not ffIf laxatives are indicated, what often reduced. Macrogol has saline e

would be the most “advanced” metabolized, therefore there is no fermentation or in-
treatment algorithm? creased gas production. Lactulose and macrogol have a
er from tol- ffect and do su ffdose-dependent laxative e
ects. ffAlways consider local herbal laxatives and foods that erance e
the patient has found useful previously, such as crushed Another class of laxatives are the nonresorbable
ns), which have both softening and lubricant ffiee oils (para ffee beans from the co ffpapaya seeds or crushed co
ects. Since they may irritate the intestinal wall, cause ffsenna tree. Th erefore, always listen to the patient and e
change therapy according to the needs of your patient. serious pulmonary damage when aspirated, and interact
For patients on permanent opioid medication, with the absorption of lipophilic vitamins, they should
prophylactic laxatives have to be prescribed simultane- only be used for a short time in complicated constipation.
ously at all times. An exception to this rule are patients A third class of laxatives has mainly stimulating
ects on the intestinal wall, causing inhi- ffwith chronic diarrhea, including many patients with ad- (propulsive) e
uids in the colon and in- flvanced HIV/AIDS who are receiving opioids to control bition of the reabsorption of
uids and electrolytes into the flt from the creasing the secretion of fineuropathic pain and who may even bene
ects of opioids. intraluminal cavity. Laxatives belonging to this class in- ffconstipating e
Some laxatives are not recommended for ex- clude the anthraquinone glycosides (aloe, senna leaves),
tended use, especially antiresorptive and secretory laxa- diphenols (bisacodyl und sodium picosulfate), as well as
tives, because they may cause considerable potassium fatty acids (castor oil). In some patients the “stimulat-
ects—especially from castor oil—may cause con- ffuid loss, which increases constipation in the long ing” e fland
term. Patients with advanced cancer and/or permanent siderable discomfort through colicky abdominal pains.
opioid therapy should not use these substances but in- Th e fourth class of laxatives are the “prokinetic”
stead should be treated stepwise with: ones, which are rarely used. Th ese include the 5-HT -re-
4
1) Macrogol or lactulose ceptor-agonist tegaserod, the macrolide antibiotic eryth-
2) Macrogol plus sodium picosulfate or senna (“soft- romycin, and the prostaglandin analogue misoprostol.
ener”)
3) Macrogol plus senna + bisacodyl (“pusher”) Is there a way to antagonize
ects ffn the intestinal e ffi4) Senna plus bisacodyl and para
4) Suppositories (glycerine or bisacodyl) of opioids directly?
5) Enemas (soap and water)
6) Manual removal of feces Using selective opioid antagonists to block the intes-
ects of opioids would be an “intelligent” ff7) In “emergencies”: castor oil, radiocontrast agent, tinal side e
or naloxone/methylnaltrexone approach to constipation therapy in patients with an