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Isotretinoin: effect, areas of application, side effects

by Josephine Andrews
Published: Last Updated on 356 views

The active ingredient isotretinoin is one of the most important medications for acne. It was approved in the USA in 1982 and is still used successfully in acne therapy today. Isotretinoin can be used internally and externally and is generally very effective. However, pregnant and breastfeeding women must not take the active ingredient under any circumstances. Here you can read everything you need to know about isotretinoin. 

How isotretinoin works

Isotretinoin is most commonly taken by mouth (orally). It reduces sebum formation (sebostatic effect), has an anti-inflammatory effect (anti-inflammatory) and counteracts blackheads (anti-comedogenic).

The active substance is a so-called retinoid, ie a natural derivative of vitamin A (collective term for several compounds with a similar effect in the body, eg retinol). Among other things , the vitamin is important for the development and regeneration of the skin .

In severe forms of acne , the pores become clogged due to increased activity of the sebaceous glands. These can then become inflamed, which leads to the typical purulent pimples and pustules in acne patients.

The supply of retinoids such as isotretinoin can help here: The active ingredients ensure increased cell growth in the upper layers of the skin ( epidermis ). The horny layer of the skin loosens up and “peeling” of the epidermis is made easier. In addition, the function of the sebaceous glands is impaired, which means that the pores are less clogged. Overall, the skin is cleansed from the inside out, the complexion is refined and there are fewer impurities.

In the first two weeks of treatment, the skin often deteriorates due to the inflammatory transformation of the skin. After that, the skin slowly and steadily begins to regenerate.

intake, degradation and excretion

After ingestion, the active ingredient isotretinoin is only incompletely absorbed from the intestine into the blood (about 25 percent). Absorption can be enhanced by taking it with a meal containing fat.

The active substance is then broken down in the liver . The breakdown products are excreted in roughly equal parts with the urine and the stool.

When applied to the skin, for example in the form of a gel, only a small amount of the active ingredient gets into the blood. The effect is practically localized, resulting in fewer side effects.

When is isotretinoin used?

The areas of application (indications) of isotretinoin include moderate to severe forms of acne that have responded inadequately to other therapeutic measures. Depending on the severity of the disease, the active ingredient is applied externally or internally. Isotretinoin may be used at an early stage, especially if there is visible scarring.

Isotretinoin is also sometimes used for other skin conditions such as rosacaea (copper rose). However, it is not approved for this type of application (off-label use).

How is isotretinoin used?

For milder forms of acne, topical application in the form of an isotretinoin cream or gel is tried first. The preparation is usually applied thinly to the affected skin areas once or twice a day.

In severe cases of illness, isotretinoin is swallowed in the form of soft capsules. The daily dose is usually 0.5 to 1 milligram per kilogram of body weight. A patient weighing 70 kilograms would take between 35 and 70 milligrams of isotretinoin daily.

For better tolerability, the active ingredient should be taken with food.

What are the side effects of isotretinoin?

Very often, i.e. in more than ten percent of those treated, isotretinoin causes side effects such as dry skin and eyes, allergic skin reactions and back pain .

Very rarely, ingestion can lead to behavioral problems, visual disturbances , hearing impairment, respiratory diseases and gastrointestinal complaints. Muscle pain is also possible. Isotretinoin also increases the skin’s sensitivity to sunlight and UV light (photosensitization).

Ensure adequate UV protection during therapy with isotretinoin.

What should be considered when using isotretinoin?


Drugs containing isotretinoin should not be used in the following cases:

  • pregnancy and breast feeding period
  • Combination with tetracyclines (group of antibiotics)
  • liver dysfunction
  • Vitamin A overdose
  • severely increased blood lipid levels


Drugs with isotretinoin must not be used together with other vitamin A preparations, otherwise there is a risk of overdose.

Taking it together with non-steroidal anti-inflammatory drugs (NSAIDs such as ibuprofen , diclofenac , naproxen ) or ciclosporin (immunosuppressant) increases the effects and side effects of isotretinoin.

Isotretinoin promotes the toxicity (poisonousness) of barbiturates (e.g. phenobarbital) and phenytoin (antiepileptic). In combination with methotrexate (including rheumatism and cancer), its liver-damaging effect can increase.

Experts recommend avoiding alcohol during isotretinoin treatment.

Driving and using machines

In rare cases, taking isotretinoin can cause night blindness and drowsiness. You should therefore pay attention to the individual reaction to the active ingredient, especially at the beginning of therapy, before you actively participate in road traffic or operate heavy machinery.

age restrictions

The active ingredient isotretinoin may only be used from the age of 12 years.

pregnancy and breast feeding period

Isotretinoin is absolutely contraindicated during pregnancy and breastfeeding and should be discontinued at least four weeks before a planned pregnancy. The reason:

The active ingredient can cause great harm to unborn children. It is therefore essential for patients to use at least one reliable method of contraception during treatment.

It is also recommended that women of childbearing potential have a pregnancy test before starting treatment and once a month during treatment. The result must be documented by the attending physician.

Regarding isotretinoin treatment in male patients: There is practically no active substance in the sperm, which is why a harmful effect on the unborn child in the event of unprotected sexual intercourse can probably be ruled out.

How to get isotretinoin medication

Drugs with isotretinoin require a prescription in Germany, Austria and Switzerland because the treatment requires regular medical checks. You can therefore only get them with a prescription from the doctor in the pharmacy.

In Austria – in contrast to Germany and Switzerland – there are currently (as of July 2nd, 2021) no local preparations (e.g. cream, gel) on the market.

Since when is isotretinoin known?

Isotretinoin was first approved in the United States in 1982. Its teratogenic effects were already known at this point.

Isotretinoin is believed to be even more “teratogenic” than thalidomide . This active ingredient was used as a sleeping pill and tranquilizer under the brand name “Contergan” in the 1950s and 60s, which ultimately led to the “Contergan scandal”:

Many pregnant women who took the drug gave birth to children with severe deformities. Since then, before a new active ingredient can be approved, tests have been required to check the effects of taking it on the unborn child.

What else you should know about isotretinoin

Treatment with isotretinoin may initially cause the symptoms of acne to worsen (known as acne “flares”). This indicates the effectiveness of the drug. However, if therapy with isotretinoin is continued, the symptoms improve quickly.

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