Macrogol Explained

Macrogol, also known as polyethylene glycol (PEG), is used as a medication to treat constipation in children and adults.[1] It is taken by mouth. Benefits usually occur within three days. Generally it is only recommended for up to two weeks. It is also used as an excipient.[2] It is also used to clear the bowels (known as "bowel prep") before a colonoscopy, when the onset of the laxative effect is more rapid, typically within an hour.[3]

Side effects may include increased bowel gas, abdominal pain, and nausea.[1] Rare but serious side effects may include an abnormal heartbeat, seizures, and kidney problems.[4] Use appears to be safe during pregnancy.[5] [1] It is classified as an osmotic laxative.[6] It works by increasing the amount of water in the stool.[7]

Macrogol came into use as a bowel prep in 1980 and was approved for medical use in the United States in 1999.[8] [9] [10] It is available as a generic medication and over the counter.[1] [11] In 2021, it was the 226th most commonly prescribed medication in the United States, with more than 2million prescriptions.[12] [13] It is also formulated together with electrolytes.[14] In 2021, the combination with electrolytes was the 295th most commonly prescribed medication in the US, with more than 500,000 prescriptions.[15]

Medical uses

Constipation

Macrogol 3350, often in combination with electrolytes, is used for short-term relief of constipation as well as for long-term use in constipation of various causes, including in multiple sclerosis and Parkinson's disease patients (an often-overlooked non-motor symptom) as well as constipation caused by pharmaceutical drugs such as opioids and anticholinergics. Whole bowel irrigation with macrogol is part of the bowel preparation before surgery or colonoscopy. Limited data also support its use for the treatment of fecal impaction.

In those with chronic constipation it works better than lactulose.[16]

A 2007 comparison showed that people with constipation had a better response to macrogol than to tegaserod. Popular types include: macrogol 3350, macrogol 4000, and macrogol 6000. The number represents the average molecular mass. Combining different molecular masses provides some control over the consistency.

Excipient

Macrogol is used as an excipient in pharmaceutical products. Lower-molecular-weight variants are used as solvents in oral liquids and soft capsules, whereas solid variants are used as ointment bases, tablet binders, film coatings, and lubricants.

For example, PEG-2000 is one of the excipients in the Moderna COVID-19 vaccine.[17] [18]

PEGylation

Macrogols are also attached to biopharmaceutical drugs to slow down their degradation in the human body and increase their duration of action, as well as to reduce immunogenicity. This process is called PEGylation.[19]

Contraindications

Contraindications for macrogol taken orally as a laxative are intestinal perforation, bowel obstruction, ileus, inflammatory bowel diseases, and toxic megacolon.

The doses of macrogol as an excipient are too low to have relevant contraindications.[20]

Allergy to macrogol is rare, and usually appears as an allergy to an increasing number of seemingly unrelated products, including cosmetics, drugs that use it as an excipient, and peri-procedural substances such as ultrasound gel.[21]

Adverse effects

Oral macrogol is generally well tolerated. Possible side effects include headache, bloating, nausea, allergies, and electrolyte imbalance, mainly hypokalaemia (low blood potassium levels) and hyperkalaemia (high blood potassium levels). Hyperkalaemia is not an effect of macrogol itself but of potassium salts which are usually part of macrogol formulations. With excessive use, it can cause diarrhea.

Interactions

The interaction potential is low. Absorption of other pharmaceutical drugs can be reduced because oral macrogol accelerates intestinal passage, but this is seldom clinically relevant. For antiepileptic drugs, such a mechanism has been described in rare cases.

Pharmacology

Mechanism of action as a laxative

Macrogol is an osmotically acting laxative; that is, an inert substance that passes through the gut without being absorbed into the body. It relieves constipation because it causes water to be retained in the bowel instead of being absorbed into the body. This increases the water content and volume of the stools in the bowel, making them softer and easier to pass, as well as improving gut motility.

Chemistry

See main article: Polyethylene glycol.

Available forms

When sold for gut cleansing (and as a laxative), it is usually in combination with salts such as sodium bicarbonate, sodium chloride and potassium chloride[22] to help mitigate the possibility of electrolyte imbalance and dehydration. Brand names include CosmoCol, Cololyt, Glycoprep, Laxido, MiraLax, Molaxole, Movicol, and Osmolax.

Polyethylene glycol-electrolyte solution is a fixed-dose combination medication sold under various brand names in the US, including Colyte,[23] Gavilyte, Golytely,[24] Nulytely,[25] Moviprep,[26] and Trilyte.[27] [28] Brand names available in the UK include CosmoCol, Klean-Prep, Laxido, Molaxole, Movicol, Plenvu, TransiSoft, and VistaPrep.[29], polyethylene glycol 3350 is available in the US as a combination with sodium sulfate, potassium chloride, magnesium sulfate, and sodium chloride and sold under the brand name Suflave.[30] It is indicated for cleansing of the colon in preparation for colonoscopy in adults.

Research

PEGylation

See main article: PEGylation.

When attached to various biopharmaceutical medications (which are proteins), macrogol results in a slowed clearance of the carried protein from the blood. This makes for a longer-acting medicinal effect and reduces toxicity, and it allows for longer dosing intervals. It also reduces the proteins' immunogenicity. Examples for PEGylated proteins include peginterferon alfa-2a and -2b, which are used to treat hepatitis C, pegfilgrastim, which is used to treat neutropenia, and pegloticase for the treatment of gout.

Nerves and spinal cords

There is evidence demonstrating PEG-induced repair of specific nerve cells in animal models:

Cancer prevention

Other

Notes and References

  1. Book: British national formulary : BNF 76 . 2018 . Pharmaceutical Press . 9780857113382 . 76 . 57–58.
  2. Web site: Macrogol as Excipient . Biesterfeld AG . 10 June 2022.
  3. Web site: Package leaflet: Information for the User - Moviprep, powder for oral solution . Medicines.org.uk. 11 February 2024.
  4. Web site: PEG-3350 and Electrolytes for Oral Solution . FDA . 19 April 2019 . 30 August 2017 . https://web.archive.org/web/20170830075931/https://www.fda.gov/downloads/Drugs/DrugSafety/UCM370635.pdf . live .
  5. Web site: Polyethylene glycol 3350 Use During Pregnancy . Drugs.com . 19 April 2019 . 28 April 2021 . https://web.archive.org/web/20210428212944/https://www.drugs.com/pregnancy/polyethylene-glycol-3350.html . live .
  6. Web site: DailyMed - polyethylene glycol 3350 powder, for solution . dailymed.nlm.nih.gov . 19 April 2019 . 26 April 2021 . https://web.archive.org/web/20210426175955/https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=49c3aa94-3b32-4929-b9c6-52e3f58e4a57 . live .
  7. Web site: Polyethylene Glycol 3350: MedlinePlus Drug Information . MedlinePlus . 19 April 2019 . 27 April 2021 . https://web.archive.org/web/20210427164616/https://medlineplus.gov/druginfo/meds/a603032.html . live .
  8. Book: Mahmoud NN, Bleier JI, Aarons CB, Paulson EC, Shangmugan S, Fry RD . Colon and Rectum . Townsend CM, Beauchamp RD, Evers BM, Mattox KL . Sabiston Textbook of Surgery E-Book: The Biological Basis of Modern Surgical Practice . 2016 . Elsevier Health Sciences . 9780323401630 . 1325 . https://books.google.com/books?id=KYstDAAAQBAJ&pg=PA1325 .
  9. Web site: Prescription Polyethylene Glycol 3350; Denial of a Hearing and Order Withdrawing Approval of Abbreviated New Drug Applications . Federal Register . 19 April 2019 . 2 April 2018 . 28 April 2021 . https://web.archive.org/web/20210428123541/https://www.federalregister.gov/documents/2018/04/02/2018-06537/prescription-polyethylene-glycol-3350-denial-of-a-hearing-and-order-withdrawing-approval-of . live .
  10. Book: Schoeman M, Nguyen NQ . Patient Preparation and Pharmacotherapeutic Considerations . Ginsberg GG, Kochman ML, Norton ID, Gostout CJ . Clinical Gastrointestinal Endoscopy E-Book: Expert Consult - Online and Print . 2011 . Elsevier Health Sciences . 9781437735703 . 87 . https://books.google.com/books?id=eKVvONAufhMC&pg=PA87 . 10.1016/B978-0-323-41509-5.00008-6 . 78762418 .
  11. Web site: Polyethylene glycol 3350 Uses, Side Effects & Warnings . Drugs.com . 19 April 2019 . 28 April 2021 . https://web.archive.org/web/20210428123121/https://www.drugs.com/mtm/polyethylene-glycol-3350.html . live .
  12. Web site: The Top 300 of 2021 . ClinCalc . 14 January 2024 . 15 January 2024 . https://web.archive.org/web/20240115223848/https://clincalc.com/DrugStats/Top300Drugs.aspx . live .
  13. Web site: Polyethylene Glycol 3350 - Drug Usage Statistics . ClinCalc . 14 January 2024.
  14. Book: Aronson JK . Glycols . Meyler's Side Effects of Drugs: The International Encyclopedia of Adverse Drug Reactions and Interactions . 2015 . Elsevier . 9780444537164 . 567 . https://books.google.com/books?id=NOKoBAAAQBAJ&pg=RA2-PA567 .
  15. Web site: Polyethylene Glycol 3350 With Electrolytes - Drug Usage Statistics . ClinCalc . 14 January 2024.
  16. Lee-Robichaud H, Thomas K, Morgan J, Nelson RL . Lactulose versus Polyethylene Glycol for Chronic Constipation . The Cochrane Database of Systematic Reviews . 7 . CD007570 . July 2010 . 20614462 . 10.1002/14651858.CD007570.pub2 .
  17. Web site: Pfizer–BioNTech COVID-19 Vaccine Standing Orders for Administering Vaccine to Persons 12 Years of Age and Older . Centers for Disease Control and Prevention (CDC) . 5 March 2021 . 2 March 2021 . https://web.archive.org/web/20210302001413/https://www.cdc.gov/vaccines/covid-19/info-by-product/pfizer/downloads/standing-orders.pdf . live .
  18. Web site: What Ingredients are in the COVID-19 Vaccine? . Connecticut Department of Public Health . 11 July 2021 . 7 July 2021 . https://web.archive.org/web/20210707232909/https://portal.ct.gov/-/media/DDS/COVID-19_2021/DPH_covidvaccine_ingredients_and_work_2_3_21.pdf . live .
  19. Porfiryeva NN, Moustafine RI, Khutoryanskiy VV . 1 January 2020. PEGylated Systems in Pharmaceutics. Polymer Science, Series C. 62. 1. 62–74. 10.1134/S181123822001004X. 226664780 . 1555-614X.
  20. Web site: Compound Macrogol Oral Powder Sugar Free. - Summary of Product Characteristics (SmPC) - (emc). www.medicines.org.uk. 10 January 2020. 28 August 2021. https://web.archive.org/web/20210828154130/https://www.medicines.org.uk/emc/product/4482/smpc. live.
  21. Wenande E, Garvey LH . Immediate-type hypersensitivity to polyethylene glycols: a review . Clinical and Experimental Allergy . 46 . 7 . 907–922 . July 2016 . 27196817 . 10.1111/cea.12760 . 1247758 .
  22. eg. Laxido package insert
  23. Web site: COLYTE- peg-3350 and lectrolytes powder, for solution . Meda Pharmaceuticals . dailymed . U.S. National Library of Medicine . February 2019.
  24. Web site: Golytely- polyethylene glycol 3350, sodium sulfate anhydrous, sodium bicarbonate, sodium chloride, potassium chloride powder, for solution . DailyMed . 28 May 2021 . 17 June 2023 . 31 March 2023 . https://web.archive.org/web/20230331093120/https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=57d22b0b-1ae0-4203-babc-f3bac17bd1c9 . live .
  25. Web site: Nulytely- polyethylene glycol 3350, sodium chloride, sodium bicarbonate and potassium chloride powder, for solution . DailyMed . 16 June 2022 . 17 June 2023 .
  26. Web site: Moviprep- polyethylene glycol 3350, sodium sulfate, sodium chloride, potassium chloride, ascorbic acid, sodium ascorbate kit . DailyMed . 15 April 2022 . 17 June 2023 . 3 February 2023 . https://web.archive.org/web/20230203145935/https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=8ff46193-2a3b-4de0-9572-775dda8cd8b2 . live .
  27. Web site: Trilyte (polyethylene glycol 3350, sodium chloride, sodium bicarbonate and potassium chloride for oral solution) with flavor packs Initial U.S. Approval: 1991 . DailyMed . 17 June 2023 .
  28. Web site: Polyethylene Glycol-Electrolyte Solution (Professional Patient Advice) . Drugs.com . 20 February 2020 . 8 June 2020 . 8 June 2020 . https://web.archive.org/web/20200608230354/https://www.drugs.com/ppa/polyethylene-glycol-electrolyte-solution.html . live .
  29. Web site: mims.co.uk . Search or browse MIMS . 24 April 2023 . 24 April 2023 . https://web.archive.org/web/20230424072604/https://www.mims.co.uk/search/drugs?keywords=Macrogol . live .
  30. Web site: SUFLAVE (polyethylene glycol 3350, sodium sulfate, potassium chloride, magnesium sulfate, and sodium chloride for oral solution) . Braintree Laboratories, Inc. . U.S. Food and Drug Administration . June 2023 .
  31. Lo MM, Tsong TY, Conrad MK, Strittmatter SM, Hester LD, Snyder SH . Monoclonal antibody production by receptor-mediated electrically induced cell fusion . Nature . 310 . 5980 . 792–794 . 1984 . 6088990 . 10.1038/310792a0 . 1984Natur.310..792L . 4357934 .

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