How active ingredient lactulose works
Lactulose is an artificial twofold sugar (synthetic disaccheride) produced starting from milk sugar (lactose). It has laxative, ammonia-binding and prebiotic properties.
Lactulose consists of the two sugars galactose and fructose. Unlike lactose, lactulose is indigestible and thus remains in the intestine. This draws water into the intestine, causing the intestinal contents to soften.
In the large intestine (colon), the laxative can be partially broken down by the bacteria found there. The resulting breakdown products (lactic acid, acetic acid and other organic acids) stimulate intestinal motility and thus facilitate bowel movements.
Another, but less frequently used, effect of these acids produced during lactulose breakdown is that they create a more acidic environment in the intestine. This is beneficial in certain liver diseases.
If the liver can no longer fulfill its detoxification function, toxic metabolic products such as ammonia accumulate in the blood in higher concentrations. This is bound by the acidic environment in the colon and thus effectively removed from the blood.
Absorption, degradation and excretion
Usually, the laxative effect, with which the active ingredient also leaves the body again, occurs after two to ten hours. However, if the dosage is insufficient, 24 to 48 hours may pass before the first bowel movement occurs.
When is lactulose used?
Lactulose is used for constipation that cannot be sufficiently improved by high-fiber diets and other general measures (adequate fluid intake, balanced diet, etc.).
The active ingredient is also given in situations that require easier bowel movements, such as after surgery in the rectal area or in cases of rectal ulcers.
Furthermore, lactulose is used in the prevention and treatment of so-called “portocaval encephalopathy,” a liver disease in which elevated ammonia blood levels occur.
It can be used as a one-time, short-term or long-term treatment.
How lactulose is used
The active ingredient is marketed as lactulose syrup (or lactulose juice) or powder. Both dosage forms can be mixed in liquid or taken undiluted, but sufficient liquid should always be drunk with it (at least one and a half to two liters daily).
What are the side effects of lactulose?
Side effects such as abdominal pain, flatulence, nausea, vomiting, and diarrhea occur in more than one in ten people treated, especially at the beginning of therapy. The severity of side effects depends on the dosage level.
With long-term use, disturbances in the water and electrolyte balance must be expected.
What should be considered when taking lactulose?
Contraindications
Lactulose must not be taken in case of:
- intestinal obstruction (ileus)
- intestinal perforation
- suspected intestinal perforation
Drug interactions
Some medications cause a loss of potassium as a side effect, such as diuretics, cortisone derivatives, and amphotericin B (antifungal agent). The laxative may increase this side effect.
Potassium deficiency can, among other things, increase the effect of cardiac glycosides (medication for heart failure). In the case of drugs with delayed release of the active ingredient (so-called retard drugs), the effect may be shortened because lactulose accelerates the intestinal passage.
To be on the safe side, the laxative should not be used in acute inflammatory gastrointestinal diseases or disorders of water and electrolyte balance.
Age restriction
Pregnancy and lactation
Drugs containing the active substance lactulose can be used during pregnancy and lactation. Previous observations speak against a teratogenic (causing malformation) effect.
Lactulose is one of the laxatives of choice during pregnancy and breastfeeding.
How to obtain medicines containing lactulose
Medicines containing the active ingredient lactulose are available only from pharmacies in Germany, Austria and Switzerland, but are not subject to prescription. However, they can be prescribed for certain underlying diseases at the expense of the statutory health insurance.
How long has lactulose been known?
In 1930, it was first described that lactulose is formed from milk sugar (lactose) by heating. In 1956, the physician Friedrich Petuely was able to demonstrate that the administration of lactulose leads to an increased number of certain lactobacilli in the stool and could thus alleviate the side effects of broad-spectrum antibiotics.
Likewise, he discovered the laxative effect from lactulose. In the 1960s, the laxative finally came onto the market in Europe.