GOL

Established / Guideline-Supported Uses

• Chronic constipation in adults and adolescents, including constipation associated with irritable bowel syndrome, for the long-term relief of symptoms. GOL is used as maintenance therapy taken daily, dissolved in water.
• Faecal (faecal) impaction — a short course of GOL at a higher, disimpaction dose is used to clear an impacted bowel before switching to a lower maintenance dose.
• Bowel cleansing / bowel preparation prior to colonoscopy, barium enema, or abdominal/colorectal surgery, where a large-volume, higher-concentration formulation of GOL is used to empty the colon completely so the bowel wall can be examined or operated on safely.

Adjunct / Combination Use

• GOL bowel-cleansing regimens are sometimes combined with a stimulant laxative (e.g., bisacodyl) or a split-dose schedule to improve the quality of colon cleansing before endoscopy, as directed by the endoscopist.

GOL is not indicated for the treatment of the underlying cause of constipation, and should not be used for weight loss or as a substitute for dietary/lifestyle measures without medical advice.

Macrogol + Electrolytes is a combined osmotic laxative preparation supplied as a powder for oral solution (sachet form). Each sachet typically contains:

• Macrogol (polyethylene glycol, PEG 3350 or PEG 4000) — the high-molecular-weight osmotic agent, in variable strength depending on the specific product (e.g., maintenance-strength or high-volume bowel-preparation strength).
• Sodium chloride
• Sodium bicarbonate (or sodium sulfate, in some bowel-preparation formulations)
• Potassium chloride

The exact quantities of macrogol and each electrolyte vary between the low-dose (maintenance) sachet and the high-volume (bowel-cleansing) sachet of Macrogol + Electrolytes; the electrolyte content is specifically balanced to minimise net absorption or loss of sodium, potassium, and water from the body when large volumes are ingested.

GOL is an osmotic laxative combination consisting of macrogol (polyethylene glycol, a large, inert polymer) together with a balanced electrolyte mixture (sodium chloride, sodium bicarbonate, and potassium chloride). It is supplied as a powder that is dissolved in water before drinking.

GOL works by retaining water within the bowel lumen through an osmotic effect, which softens the stool, increases stool bulk, and stimulates the natural urge to defecate, without being significantly absorbed into the bloodstream or metabolised by the body. The accompanying electrolytes are included so that, even when patients drink large volumes for bowel cleansing, there is minimal net gain or loss of body sodium, potassium, or water.

GOL is used both as a once- or twice-daily maintenance treatment for chronic constipation and, in a different (higher-volume) formulation and dose, as a same-day or split-dose bowel-cleansing preparation before colonoscopy or bowel surgery.

GOL belongs to the osmotic laxative class of medicines, and its high-volume formulation is additionally classified as a bowel evacuant / bowel-cleansing preparation used for pre-procedure gut preparation.

Mechanism of Action

The macrogol (polyethylene glycol) component of Macrogol + Electrolytes is a long-chain polymer that is neither absorbed from, nor metabolised in, the gastrointestinal tract. It forms hydrogen bonds with water molecules, holding water within the bowel lumen and preventing its absorption across the gut wall. This osmotic retention of water increases the volume and softness of the stool and mechanically stimulates colonic motility (peristalsis), producing a bowel movement typically within 24–48 hours for the constipation indication, or rapid, repeated watery evacuation within 1–2 hours at the high doses used for bowel cleansing.

Role of the Electrolytes

The added sodium chloride, sodium bicarbonate, and potassium chloride in Macrogol + Electrolytes create an iso-osmotic (electrolyte-balanced) solution. This balance is specifically designed so that, when the solution passes through the gut, there is no significant net movement of the body's own sodium, potassium, or water into or out of the bloodstream — an important safety feature, particularly for the large volumes used in bowel-preparation regimens.

Pharmacokinetics

Macrogol + Electrolytes acts locally within the gastrointestinal tract. The macrogol component is essentially not absorbed systemically and is excreted unchanged in the faeces; only a very small fraction of the electrolyte load is absorbed under normal use.

Each sachet of GOL should be emptied into the exact volume of drinking water stated on the pack (this varies between the maintenance-strength and bowel-preparation-strength sachets) and stirred until fully dissolved before drinking. The reconstituted solution should generally be consumed promptly, and any prepared solution not used within the time stated on the label (commonly within a few hours) should be discarded and freshly prepared. GOL may be taken with or without food for the constipation indication; for bowel preparation, follow the specific fasting/fluid instructions given by the treating physician or endoscopy unit. Doses of other oral medicines should ideally be separated in time from GOL intake (see Drug Interactions).

Because GOL produces rapid transit of fluid through the gut and increases stool water content, it can reduce the absorption of other orally administered medicines if taken at the same time; other oral drugs should generally be taken at least 1–2 hours before or after GOL, particularly for drugs with a narrow therapeutic index.

Because GOL carries a sodium, potassium, and fluid load, caution and closer monitoring are advised when it is used together with medicines that also affect fluid or electrolyte balance, such as diuretics, ACE inhibitors, or angiotensin receptor blockers, as the combination may increase the risk of electrolyte disturbance, particularly in patients with renal or cardiac impairment.

Common

• Abdominal bloating and distension
• Abdominal pain or cramping
• Nausea
• Flatulence

Less Common

• Vomiting
• Diarrhoea (usually a sign that the dose of GOL needs to be reduced)
• Perianal soreness or irritation with prolonged use

Rare

• Hypersensitivity reactions, including skin rash, urticaria, angioedema, and, very rarely, anaphylaxis
• Fluid or electrolyte disturbances (e.g., hyponatraemia, hypokalaemia) with excessive intake, prolonged use, or in at-risk patients

Pregnancy: GOL is minimally absorbed from the gut, and available data have not shown it to be teratogenic; however, it should be used during pregnancy only if clearly needed and if the potential benefit justifies the potential risk, and only under medical advice, particularly for the high-volume bowel-preparation regimen.

Lactation: Because systemic absorption of the macrogol component of GOL is minimal, it is generally considered compatible with breastfeeding when used at usual doses for constipation; nevertheless, a physician or pharmacist should be consulted before use during breastfeeding, especially for the bowel-preparation regimen.

• Cardiac impairment: Use GOL with caution in patients with significant cardiac disease (e.g., heart failure), as the fluid and electrolyte shifts produced by large-volume regimens may precipitate cardiac arrhythmia or pulmonary oedema.
• Renal impairment: Use with caution and consider closer monitoring of fluid and electrolyte status in patients with impaired renal function, who are less able to correct any electrolyte disturbance caused by GOL.
• Sodium-restricted diet: Patients on a sodium-restricted diet should be counselled that GOL contains sodium, and its use should be discussed with a physician.
• Elderly and debilitated patients: Use GOL with additional caution, and under supervision, in frail, elderly, or bedridden patients, and in those with impaired swallowing or a reduced gag reflex, because of the risk of regurgitation or aspiration with large-volume regimens.
• Unexplained abdominal pain: GOL should not be started until serious organic disease (including bowel obstruction and perforation — see Contraindications) has been excluded in a patient with undiagnosed abdominal pain.
• Prolonged use: Long-term, unsupervised use of GOL should be avoided; persistent constipation despite treatment should prompt medical review of the underlying cause.

Overdose with GOL is most likely to present as severe diarrhoea and vomiting, which can lead to significant fluid loss and electrolyte disturbance (particularly of sodium and potassium), especially in young children, the elderly, or patients with pre-existing renal or cardiac disease. There is no specific antidote. In case of a suspected overdose, stop further doses and seek immediate medical attention or contact the nearest hospital emergency department or a poison-control service; treatment is generally supportive, with correction of fluid and electrolyte imbalance under medical supervision.

Store at room temperature (below 30°C), away from light and moisture. Keep out of reach of children.

Renal Impairment

Use GOL with caution and consider more frequent monitoring of fluid and electrolyte status in patients with significant renal impairment (see Precautions and Warnings).

Hepatic Impairment

No specific dose adjustment is established; general caution is advised as with any patient receiving a large fluid/electrolyte load.

Elderly

GOL can be used in elderly patients, but with additional caution in those who are frail, immobile, or have swallowing difficulty, given the higher risk of fluid/electrolyte disturbance and aspiration (see Precautions and Warnings).

Children

See Paediatric Uses below; only specific age-appropriate formulations and doses of GOL are established for children, and use in young children should always be supervised by a physician.

For chronic constipation, GOL is typically continued at the lowest effective maintenance dose for as long as needed to keep stools soft and regular, with periodic medical review, particularly if used beyond a few weeks. For faecal impaction, the higher disimpaction dose of GOL is normally used for a short course (commonly up to 3 days) before returning to a maintenance dose. For bowel preparation before colonoscopy or surgery, GOL is used as a single, one-off course completed shortly before the scheduled procedure, exactly as instructed by the endoscopist or surgeon.

GOL is supplied as a powder that must be reconstituted before use. Empty the contents of one sachet into the exact volume of drinking water specified on the product label (the volume differs between the low-dose maintenance sachet and the high-volume bowel-preparation sachet) and stir well until completely dissolved. The resulting solution may have a faint characteristic taste; it may be chilled or flavoured with a small amount of sugar-free squash if permitted by the product labelling, to improve palatability for large-volume bowel-preparation regimens. Any reconstituted solution of GOL that is not consumed within the time stated on the pack (commonly within about 6 hours) should be discarded and a fresh solution prepared.

Macrogol + Electrolytes is classified as an osmotic laxative; its high-volume, high-strength formulation is further classified as a bowel evacuant / gastrointestinal lavage (bowel-cleansing) preparation.

Macrogol + Electrolytes works purely osmotically within the bowel: the macrogol component binds water molecules and holds them in the intestinal lumen, softening and bulking the stool and mechanically triggering peristalsis, while the accompanying electrolytes are balanced so that fluid and salts are neither significantly absorbed into, nor lost from, the body during treatment.

Use of GOL in children should always be under the guidance of a paediatrician. Specific paediatric-strength sachets/doses of macrogol-electrolyte products are established for the treatment of constipation and faecal impaction in children from around 2 years of age and older, with the dose calculated by age and adjusted to clinical response; treatment in very young children (under 2 years) should only be undertaken with direct medical supervision, as safety and efficacy in this age group are less well established. The high-volume bowel-preparation formulation of GOL used before colonoscopy is generally reserved for older children/adolescents under direct medical/endoscopy-unit supervision, with the dose and volume individualised by the treating team; safety and efficacy of the bowel-preparation regimen have not been formally established in very young children.