Active Ingredients

Isotretinoin – Effect, Application & Risks


The drug isotretinoin is an important means of treating acne . It is used internally and externally.

What is isotretinoin?

Isotretinoin is also called 13-cis-retinoic acid . What is meant by this is a cis isomer of tretinoin. The active ingredient is one of the non-aromatic retinoids. As a positional isomer of retinoic acid, isotretinoin is a component of vitamin A metabolism.

Isotretinoin was first approved in the United States of America in 1982. The teratogenic effect of the substance could already be proven at that time. Isotretinoin is said to have a stronger teratrogenic effect than thalidomide , which brought it to dubious notoriety through the drug thalidomide and triggered the thalidomide scandal. Numerous children of pregnant women who had taken Contergan were born with deformities. For this reason, isotretinoin should not be used during pregnancy . The pharmaceutical company Roche released the active ingredient in the 1980s for the treatment of severe acne under the product name Accutane®.

Pharmacological action

Isotretinoin is one of the retinoids, which form natural derivatives of vitamin A and are found widely in the human body. They cause accelerated cell growth .

If a person suffers from acne, this leads to clogging of the pores due to the increased activity of the sebaceous glands , which in turn leads to their inflammation . This becomes noticeable through purulent pustules and pimples . However, if the body receives additional retinoids through the use of isotretinoin, these bind to the corresponding receptors , which leads to increased cell growth in the upper layers of the skin . The consequence of this is the loosening of the horny layer of the skin. This allows the epidermisbe peeled off more easily. At the same time, the sebaceous glands are impaired, so that the clogging of the pores is reduced.

The exact mechanism of action of isotretinoin has not yet been fully established. What is clear, however, is that suppressing skin oil production and reducing the size of the sebaceous glands lead to an improvement in acne symptoms. In addition, isotretinoin has anti-inflammatory effects. This cleans the skin from the inside, which can be recognized by a finer complexion with fewer impurities.

If isotretinoin is administered orally, only about 25 percent of the active ingredient gets from the intestine into the blood . The substance is broken down in the liver . Isotretinoin is eliminated from the body in stool and urine . In the case of external use, this results in a local effect of isotretinoin. Only small amounts are absorbed by the blood, so the risk of side effects is also significantly lower.

Medical Application & Use

Isotretinoin is administered for the treatment of mild to moderate acne that is inflammatory or non-inflammatory. Depending on the severity of the skin disease, the drug is administered internally or externally. With a particularly pronounced course of acne, isotretinoin can also be taken in tablet form.

On the other hand, if the acne is mild or moderate, isotretinoin is used as a gel or cream. The patient usually applies a thin layer of the remedy to the affected areas of skin once or twice a day. If the course is severe, soft capsules are taken orally with a daily dose of between 0.5 and 1.0 milligrams per kilogram of body weight. It is recommended that isotretinoin be taken with meals as it is then better tolerated. Isotretinoin is only available in pharmacies upon presentation of a doctor’s prescription.

Risks & side effects

Isotretinoin use can be associated with undesirable side effects, especially when taken internally. About 10 percent of all patients suffer from side effects. These include inflamed or dry lips , eye irritation, inflammation of the conjunctiva , dry skin , skin rash , itching , excess or lack of blood platelets , anemia (low blood count), muscle pain , joint problems, disorders of lipid metabolism, nasopharyngeal inflammation , nosebleeds , headaches asblood in the urine .

Back pain is not uncommon in adolescent patients . Only occasionally do hypersensitivity reactions, hair loss or allergies occur .

Some side effects depend on the dose of isotretinoin. If the dose is reduced or the therapy is discontinued, the side effects disappear in most cases. When used externally, side effects such as skin irritation, burning , itching, redness , lightening of the skin and sensitivity to light can occur. In most cases there is also an increased risk of sunburn . In individual cases, taking isotretinoin leads to drowsiness and night blindness , which can limit the ability to drive.

Under no circumstances should isotretinoin be used during pregnancy and breastfeeding . The reason for this is a significant malformation-promoting effect of the drug. Another contraindication is hypersensitivity to isotretinoin. Since the active ingredient, together with sunlight, promotes the degeneration of skin cells into skin cancer , exposure to UV light must be avoided.

Internal use should be avoided in the case of high vitamin A concentrations in the body, lipid metabolism disorders that are associated with increased blood lipid levels, and liver function disorders . During isotretinoin treatment, for example, the patient is not allowed to donate blood to protect pregnant women from blood containing isotretinoin.

Attention should also be paid to interactions that can arise from the simultaneous intake of isotretinoin with other medicines. There is a risk of an increase in intracranial pressure when using antibiotics such as tetracyclines . In addition, isotretinoin should not be administered at the same time as other vitamin A preparations, as this could lead to an overdose.

Lisa Newlon
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Hello! I am Lisa Newlon, and I am a medical writer and researcher with over 10 years of experience in the healthcare industry. I have a Master’s degree in Medicine, and my deep understanding of medical terminology, practices, and procedures has made me a trusted source of information in the medical world.