Excipients of your medicines

A medicinal product is composed of active ingredients, i.e. one or more substances that act to treat, as well as other substances, called excipients.

• The active substance is a substance of natural or chemical origin that allows the medicine to act in your body, either to treat a disease or to prevent it.
• The excipient itself has no therapeutic effect. It is used to make medicines easier to use. For example, to help your body absorb the active substance, stabilise the medicine, or provide its shape, colour or taste.

Two good reasons to pay attention to the excipients of your medications

1. The composition of a given medicinal product generally changes very little over time. In contrast, its generic medicinal product (a copy of the existing one), or a biosimilar of a medicinal product of biological origin, may contain excipient(s) different from those of the original medicinal product (“brand-name drugs”).
2. Some excipients are called "excipients with known effect" because they can influence your body. Usually, these effects are mild. However, in some people, they may be more important and require discontinuation or substitution of the medicine.

What are the excipients with known effect?

These are excipients whose presence may require precautions for use in some patients. The European Medicines Agency (EMA) has established a list of excipients “with a known action or effect”.[1] These include:

• Certain alcohols (ethanol, benzyl alcohol, propylene glycol),
• Oils (rice, sesame, …)
• Sugars (glucose, lactose, sorbitol, … sucrose)
• Parabens,
• Sulphites and metabisulphites, etc.

Example of lactose-containing medicines

Lactose is an excipient with a known effect.

It is a natural sugar, consisting of galactose and glucose, found mainly in milk. It is used during the manufacturing of certain medicines, vitamins and sweeteners.

Lactose used as an excipient can be prepared from cow’s milk and then it contains very small traces of milk proteins (casein and beta-lactoglobulin), which is not the case if it is of synthetic origin (without milk proteins).

Lactose intolerance

Some people are lactose intolerant.

This intolerance is associated with poor digestion of lactose, due to a lack of lactase (the digestive enzyme that digests lactose). Undigested lactose ferments in the intestine and can cause uncomfortable digestive symptoms (bloating, gas, abdominal pain, diarrhea…).

• If a medicine contains lactose (from cow's milk or synthetic) it can lead to this type of digestive disorder.
• In people who are lactose intolerant, lactose-containing medicines should be avoided as much as possible.

Cow's milk allergy

Some people are allergic to cow's milk.

This allergic reaction mainly affects infants and young children. The diagnosis is made by an allergist using specific tests.

This allergy is not associated with the presence of lactose, but with the two main proteins in cow’s milk (casein and beta-lactoglobulin).

• People with allergies or suspected cow’s milk allergies should not receive medicines containing lactose of bovine origin and administered as an injection, as they may contain traces of protein. This is the case for some injectable corticosteroids. This contraindication is then clearly mentioned in the package leaflet of the medicinal product.
• This contraindication does not apply to medicinal products taken orally or inhaled, as the allergy risk is very low in this case. However, patients who have already experienced a reaction after taking a lactose-containing product should avoid them as much as possible.

Example of drugs containing sorbitol

Sorbitol is another excipient with a known effect.

This sugar is transformed by the body into fructose by the enzyme called sorbitol dehydrogenase, mainly in the liver.

Sorbitol malabsorption

Some people poorly digest sorbitol (sorbitol malabsorption). They should, therefore, avoid it in their diet and in the medicines to minimise digestive problems such as bloating, flatulence, abdominal pain/cramps, nausea, loss of appetite and diarrhea.

It is important to know that the presence of sorbitol in medicines (or in certain food, including so-called ‘sugar-free’ products) can worsen the malabsorption of fructose. This situation, which is also common, is manifested by digestive disorders (ballooning, gas, stomach pain, nausea, diarrhea).

People with hereditary fructose intolerance have a rare and severe genetic disease, associated with the deficiency in an enzyme called aldolase B.

In this case, even very small amounts of fructose, sorbitol or sucrose can cause serious health problems, because the liver is not able to metabolize them properly.

This leads to an accumulation of toxic substances in the body, which can cause:

• Severe liver, kidneys or intestines damage,
• Sugar metabolism disorders with hypoglycaemia (decrease in blood sugar levels),
• And sometimes bleeding disorders (difficulties in ceasing bleeding).

Fortunately, this disease is rare (1 in 20,000 individuals in Europe). People concerned must be extremely vigilant and check the composition of their medicinal products and any other product consumed, to avoid any substance containing fructose, sorbitol or sucrose (composed of glucose and fructose).