The drug isotretinoin represents an important agent for the treatment of acne. Its application takes place internally and externally.
What is isotretinoin?
The drug isotretinoin represents an important agent for the treatment of acne. Its application takes place internally and externally. Isotretinoin is also called 13-cis-retinoic acid. This refers to a cis-isomer of tretinoin. The active ingredient belongs to the non-aromatic retinoids. As a positional isomer of retinoic acid, isotretinoin forms a component of the vitamin A metabolism. Isotretinoin was first approved for use in the United States in 1982, at which time it was already shown to have a harmful effect on fertility. Isotretinoin is said to have a stronger teratrogenic effect than thalidomide, which gained dubious notoriety through the drug thalidomide and triggered the thalidomide scandal. Numerous children of pregnant women who had taken thalidomide were born with deformities. For this reason, isotretinoin must not be used during pregnancy. The pharmaceutical company Roche brought out the active ingredient in the 1980s for the treatment of severe acne under the preparation name Accutane.
Pharmacologic action
Isotretinoin belongs to the retinoids, which are natural derivatives of vitamin A and are widely found in the human body. They cause accelerated growth of cells. 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 causes their inflammation. This becomes noticeable through purulent pustules and pimples. However, if the body receives additional retinoids through the application of isotretinoin, they 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 makes it easier to exfoliate the epidermis. At the same time, there is an impairment of the sebaceous glands, so that the clogging of the pores is reduced. The exact mechanism of action of isotretinoin has not yet been fully determined. However, it is clear that the suppression of skin fat production and the reduction of the size of the sebaceous glands lead to an improvement in acne symptoms. In addition, isotretinoin has anti-inflammatory effects. This leads to a cleansing of the skin from the inside, which can be recognized by a finer skin appearance with fewer impurities. If isotretinoin is applied orally, only about 25 percent of the active substance passes from the intestine into the blood. The substance is broken down in the liver. Isotretinoin is excreted from the body via stool and urine. In the case of external application, this results in a local effect of the isotretinoin. Only small amounts are absorbed from the blood, so the risk of side effects is also significantly lower.
Medical application and use
Isotretinoin is administered for the treatment of minor to moderate acne that is inflammatory or noninflammatory. Depending on the severity of the skin condition, the drug is administered internally or externally. If the acne is particularly severe, isotretinoin can also be taken in tablet form. If, on the other hand, the acne is mild or moderately severe, isotretinoin is used as a gel or cream. The patient usually applies a thin layer of the product to the affected skin areas once or twice a day. In severe cases, soft capsules are taken orally in 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 at pharmacies upon presentation of a doctor’s prescription.
Risks and side effects
The use of isotretinoin may be associated with undesirable side effects, which is particularly true for internal use. For example, 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, an excess or deficiency of blood platelets, anemia (anemia), muscle pain, joint problems, disorders of lipid metabolism, nasopharyngitis, nosebleeds, headaches, and blood in the urine. In adolescent patients, back pain is not uncommon.Only occasionally hypersensitivity reactions, hair loss or allergies exist. Some side effects depend on the dosage of isotretinoin. If the dose is reduced or the therapy is discontinued, the side effects also disappear in most cases. External use may cause side effects such as skin irritation, burning, itching, redness, lightening of the skin, and photosensitivity. In most cases, there is also an increased risk of sunburn. In individual cases, the use of isotretinoin leads to drowsiness and night blindness, which may impair the ability to drive. Isotretinoin must not be used during pregnancy and breastfeeding. The reason for this is that the drug has a considerable protogenetic effect. 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 cases of high vitamin A concentrations within the body, lipid metabolism disorders associated with elevated blood lipid levels, and liver function disorders. During isotretinoin treatment, the patient must not donate blood, for example, in order to protect pregnant women from blood containing isotretinoin. Attention must also be paid to interactions that may arise from the simultaneous use of isotretinoin with other medications. For example, there is a risk of an increase in intracranial pressure when antibiotics such as tetracyclines are used. In addition, isotretinoin should not be administered at the same time as other vitamin A preparations because of the risk of overdose.
