LAXATIVES
STIMULANT LAXATIVES: These are medications that promote bowel movements by stimulating the intestinal walls, often used for short-term treatment of constipation.
on set of action 6-12hours
Examples include bisacodyl , senna , co-dranthamer , co-danthrusate , Docusate sodium (acts as a stimulant and softening agent), sodium picosulfate. Glycerol suppositories acts as a lubricant and as a rectal stimulant.
Excessive use of stimulant laxatives can cause : Diarrhoea , dehydration , hypoklamaeia .
side effects : Flatulence (farting), abdominal cramps , diarrhoea , and nausea , some stimulant laxatives cause melanosis coli ( reversible pigmentation of the intestinal walls)
BULK FORMING LAXATIVES: These work by absorbing water in the intestine, which increase the bulk and moisture of the stool. Stimulating the bowel movements to contract more effectively , promoting movement in the GI tract.
onset of action 12-72 hours after digestion
Examples include : Methycellulose , Ispahula husk , and sterculia
side effects : Abdominal distension, bronchospasms , conjunctivits ; gastrointestinal disorders , hypersensitivity , rhinitis and skin reactions
FAECAL SOFTENERS : They work by increasing the amount of water and fat your stool absorbs. Making it easier to pass stool .
onset of action up to 72 hours
Examples include : docusate sodium , docusate calcium , Glycerol , arachis oil
side effects : Flatulence (farting), abdominal cramps , diarrhoea , and nausea , some stimulant laxatives cause melanosis coli ( reversible pigmentation of the intestinal walls)
OSMOTIC LAXATIVES : increase the amount of water in the colon (large intestine) , by holding water in the stool, maintaining its volume and stimulating peristalsis.
onset of action 2-3 days to work
Examples include : Macrogal 3350, Lactulose
side effects : Flatulence (farting), abdominal cramps , diarrhoea , and nausea , some stimulant laxatives cause melanosis coli ( reversible pigmentation of the intestinal walls)
PRUCALOPRIDE : A selective serotonin 5HT4-receptor agonist with prokinetic properties. Works by increasing peristalsis in the colon, increasing bowel movements in the colon.
indication and dose : Chronic constipation when other laxatives fail to provide an adequate response
Contr-indications : Crohns disease , intestinal obstruction , ulcerative colitis
Patient counseling on Laxatives
Laxatives can be taken with or without food
Oral solutions can be taken as they are or diluted in another liquid
powdered forms are dissolved in liquid
In order for laxative to work they must drink plenty of water aim for at least 6-8 glasses of liquid per a day
If they are regularly passing more than two or three soft stools per day , the dose should be reduced or the laxative should be stopped (unless its being used for hepatic encephalopathy)
Monitoring & Stopping
In a hospital setting , a stool chart is useful to monitor the side effects of the treatment. This is particularly important when treating hepatic encephalopathy, where you should also monitor electrolytes. Where the cause for constipation is treated or resolves (e.g. cessation of opioid therapy), laxatives can often be stopped.
When prescribing opioid analgesics to be taken regularly, consider co-prescribing a laxative to prevent constipation. A stimulant (e.g. senna) is a reasonable choice. Constipation is uncomfortable and can contribute to confusion in older people. Pre-empting opioid-induced constipation can increase adherence to treatment, improve symptoms and reduce complications such as delirium.