A B C D E F G H I J K L M N O P R S T U V W

LAXATIVES

What are the types of Laxative?

Bulk forming laxatives consist of bran (Trifyba), ispaghula husk (Fybogel, Konsyl, Isogel, Regulan), methylcellulose (Celevac) and sterculia (Normacol and Normacol Plus). All except Celevac are powders or granules that need to be mixed with water before taking. Stimulant laxatives are bisocodyl, dantron (Co-danthramer, Co-danthrusate), docusate sodium (Dioctyl, Docusol, Fletcher’s enema, Norgalax Microenema), glycerol, senna (Senokot, Manevac) and sodium picosulphate. There are a number of other products that come into this category. They can be purchased in a pharmacy but are not available on prescription (eg syrup of figs). Softeners are arachis oil and liquid paraffin. Osmotic laxatives consist of lactitol, lactulose, macrogols (Movicol), magnesium salts, phosphate (Carbalax, Fleet Ready-to-Use Enema, and Fletcher’s phosphate enema) and sodium citrate (Microlette Micro-enema, Micralax Micro-enema and Relaxit Micro-enema).

What are Laxatives for ?

Laxatives are used to treat constipation. This is when you open your bowels less often than is comfortable, so that the motions are hard, difficult or painful to pass. If you are bed-ridden because of illness, after an operation or childbirth, a lack of exercise and the correct type of food may have caused the problem. Laxatives are also used to prepare the bowel for certain x-ray and other examinations, or for operations. Certain antidepressants and painkillers may also slow down the bowel, so that some form of laxative is desirable.

How do Laxatives work ?

Bulk forming laxatives work by absorbing lots of water into your bowel. This increases the bulk of your bowel motions. In turn, this stimulates the bowel to contract and makes the motions easier to pass. Stimulant laxatives work on the nerves in the wall of the bowel. They directly stimulate the bowel to contract and so expel the motions more quickly. Softeners do just that! The motions become easier to pass. Osmotic laxatives work by keeping fluid in the bowel (instead of it being absorbed from the bowel). Again this makes the motions softer and easier to pass.

How should Laxatives be used ?

Laxatives are usually taken at bed-time so that they work overnight. This encourages a bowel action next morning. Bulk forming and osmotic laxatives take up to 2 days to begin working. Because of this, these types of laxatives need to be taken every day in order to keep the bowel habit regular. Stimulant laxatives, and any other which contain magnesium, act more quickly. You can take them just when you need them. Ideally, you should only use a laxative over a short period. Then keep your bowel habit regular with fluid, a high fibre diet and with exercise.

During Treatment with Laxatives

If you use laxatives for a long time, your bowel can become dependent on them. It will then be hard to wean yourself off them. In addition, the stimulant laxatives can cause bowel cramps and diarrhoea, sometimes leading to dehydration. Osmotic laxatives can cause a lot of wind. Any laxative when taken in excess can sometimes cause quite serious chemical imbalance. The potassium level of the blood gets too low, and this can cause weakness and even heartbeat irregularities. Even the bones can suffer by too much phosphate being "flushed out". If any laxative causes diarrhoea, the dose is too high for you. Discuss the situation with your doctor.

Drug Interference

If used in the correct way, laxatives do not interfere with any drug. However, a low potassium is a particular risk if you are on "water tablets" (diuretics). These also tend to make you lose potassium.

What if Laxatives are not taken ?

Probably nothing too serious. When you feel that you no longer need it, it is safe to stop taking your laxative without first seeing your doctor. To try and avoid your constipation coming back again, increase your fluid (up to eight cups or glasses a day), eat more fresh fruit and vegetable (to build up your fibre intake) and take more exercise. Even walking helps.

General advice on using Laxatives

You should tell your doctor if you have stomach pain as well as constipation. You may have a blockage in your bowel, and it would be important to find this out. It could even be dangerous to take laxatives under those conditions. If you are over 40 and your constipation starts for the first time, do tell your doctor. He or she may feel that you need tests to see whether there is anything serious wrong with your bowel before suggesting a laxative. If you have any other questions which are not answered by this leaflet, please ask your doctor or pharmacist. Keep this leaflet handy in case you wish to refer to it at a later date.