Macrogol

Macrogol, also known as polyethylene glycol (PEG), is a laxative that forms its own group, the macrogols. There are many different macrogols, all with a number as an epithet indicating their molecular weight. The best known are macrogol 3350 and macrogol 4000. Macrogol is used to treat constipation and to empty the bowels. Due to its ability to bind water, the stool becomes more fluid and thus has a laxative effect. Macrogol is not metabolized or absorbed. Macrogol is often used in medicines in combination with salts such as potassium chloride or sodium chloride. Macrogols are linear and therefore form very long chains. Depending on the molecular mass, macrogol is a viscous liquid (200-400 g/mol) or a white solid substance (>3000 g/mol). Due to its many oxygen atoms, polyethylene glycol is highly soluble in water. Macrogol can also be used before colonoscopies to empty the bowel.

Macrogol works by binding water. Due to the high number of oxygen atoms, macrogol has the ability to bind many water molecules via hydrogen bonds. The increased water in the intestine increases the stool volume, which in turn activates the bowel evacuation stimulus. This results in increased intestinal motility, i.e. increased intestinal movements and therefore not only an increased urge to defecate, but also softer stools.

Polyethylene glycol takes effect approx. 1-2 hours after oral ingestion. It is excreted unchanged in the stool. Only very minimal amounts are absorbed, which are excreted in the urine and result in a maximum plasma concentration (Cmax), i.e. the maximum concentration of the active ingredient in the blood plasma (liquid cell-free portion of the blood), which after ingestion of 140 grams is a Cmax of 2.7 micrograms after 3 hours. To illustrate the low absorption power: This would be 0.000002% absorption at the above values. The half-life, i.e. the time the body needs to excrete half of the active substance, is 4.1 hours on average.

Always take Macrogol exactly as described in the package leaflet or as advised by your doctor.

The usual recommended dose for adults and children aged 8 years and over is 10-20 g per day. It should usually be dissolved in water. 50 ml of water per 10 g of macrogol. It should preferably be taken in the morning.

The following side effects may occur:

In children:

• Common:
  • Abdominal pain
  • Diarrhea
• Occasional:
  • Nausea and vomiting
  • Flatulence
• Frequency not known:
  • Allergic reactions

In adults:

• Frequent:
  • Abdominal pain
  • Flatulence
  • Nausea
  • Diarrhea
• Occasional:
  • Vomiting
  • Urge to defecate
  • Fecal incontinence
• Frequency not known:
  • Low blood potassium levels and associated cardiac arrhythmias
  • low blood sodium levels and associated fatigue, muscle twitching and seizures that can lead to coma
  • Lack of fluids, due to severe diarrhea
  • Allergic reactions

Interactions may occur if the following medicines are taken at the same time:

• with drugs that have a narrow therapeutic range or a short half-life. These include, for example, digoxin, antiepileptics, coumarins and immunosuppressants. The effect may be weakened.
• with thickening agents - Macrogol can counteract thickening agents

The therapeutic width is a parameter in pharmacy that indicates how safe a drug is. The therapeutic width is the distance from the therapeutic effect to the toxic effect. It is calculated by dividing the LD50 (lethal dose), i.e. the dose at which 50% of the test animals die, by the ED50 (effective dose), i.e. the dose at which 50% of the test animals experience a therapeutic effect.

Macrogol must NOT be taken in the following cases:

• if you are allergic to macrogol
• in the case of inflammatory bowel diseases such as ulcerative colitis, Crohn's disease or abnormal bowel dilation
• in the event of an intestinal perforation or if there is a risk of an intestinal perforation
• in the event of an intestinal obstruction or suspected intestinal obstruction

Macrogol can be taken from the age of 8.

Macrogol can be taken as indicated during pregnancy. It has been used for decades in pregnancy to treat constipation. Risks of malformations have not been observed and are not to be expected due to the lack of absorption in the intestine. No risks of malformations were found in animal studies either. However, the study situation is very sparse.

Macrogol can be taken as indicated during breastfeeding . No abnormalities have been observed in infants, which are not to be expected due to the lack of absorption in the intestine. There are no studies on the use of Macrogol during breastfeeding.