DermNet NZ

Facts about the skin from DermNet New Zealand Trust. Topic index: A B C D E F G H I J K L M N O P Q R S T U V W X Y Z


Properties | Indications for treatment | Dosage | Side effects | Drug interactions
Monitoring | Pregnancy | Slow responders | Relapses

Isotretinoin or 13-cis retinoic acid is a very effective medication for the treatment of acne. It is a retinoid; this means it is derived from vitamin-A (retinoic acid). The liver naturally makes small quantities of isotretinoin from vitamin-A, but the drug we prescribe is made synthetically.

Isotretinoin has been available in New Zealand since 1982 and originally received Drug Tariff funding only on the prescription of a Vocationally Registered (Specialist) Dermatologist. Since March 2009, subsidy has been available on Special Authority application by dermatologists and vocationally registered general practitioners. Restrictions apply. In New Zealand, isotretinoin is available as 10 mg and 20 mg capsules, trade name Oratane® (September 2009). In other countries, there are other brands of isotretinoin including Isotane®, Claravis®, Isotroin®, Epuris®, Sotret®, Amnesteem®, Myorisan®, Absorica®, Zenatane® and others. The original brand, Accutane®/Roaccutane®, is no longer available.

Most people receive a course of isotretinoin for 16 to 30 weeks (4 to 7 months), but some require it for longer. In some cases, continued treatment may be prescribed long term, usually in low dose or intermittently. If necessary, it can be prescribed for children for a short course. Long term use in children under 13 years is best avoided because of a risk of premature epiphyseal closure (stopping growth).

If you are prescribed isotretinoin it is very important you read and understand about the medication. Ask your dermatologist to explain anything you do not understand.

Do not give your medication to anyone else. Do not start the medication if you are pregnant, and do not become pregnant during treatment as this medication may cause major birth defects.

Do attend all booked appointments with your dermatologist. Do not hesitate to phone your doctor or dermatologist if you have any concerns about your treatment.

Properties of isotretinoin

Indications for treatment with isotretinoin

Dermatologists prescribe isotretinoin for patients with acne in the following circumstances:

Isotretinoin is also useful for patients severely affected by other follicular conditions. These include:

Isotretinoin has proved helpful as a second-line treatment for scaly skin conditions and other inflammatory skin diseases such as:

Dosage of isotretinoin

The individual dose prescribed by the dermatologist depends on:

For severe acne, the total dose over a course of treatment is ideally between 120 and 150-mg/kg-body weight. The range of doses used each day for acne is 0.1 to over 1mg/kg body weight. Generally the side effects are easier to cope with if one starts with a reasonably small dose, perhaps 0.5mg/kg/day. The dose can be gradually increased over the next few weeks depending on tolerance and its effect on the skin condition. Sometimes it needs to be reduced or even temporarily stopped. Your dermatologist will advise you.

The medication requires fat to help its absorption into the bloodstream so it is taken after food. This can be as a single daily dose after the main meal of the day, swallowed with water or another non-alcoholic drink.

If you forget your daily dose, do not double up the next day. The occasional missed dose will not make much difference to the outcome of the treatment.

Drug interactions with isotretinoin

Isotretinoin should not be taken with the following medications:

Warfarin may have its effect reduced by isotretinoin so the combination should be used with caution and INR monitoring should be undertaken.

Side effects of isotretinoin

Unfortunately isotretinoin can make acne worse at first. Usually the flare-up lasts only a couple of weeks, but in some people the flare-up can be very severe and occur for several months. If you have a severe flare-up of your skin condition, let your dermatologist know straight away. Additional medication such as oral steroids, antibiotics or acne surgery (cautery of comedones) may be required, and the dose of isotretinoin may need to be adjusted.

All treated patients suffer from some side effects. The range and severity of the side effects depends on the disease being treated, the dose of isotretinoin and personal factors. Contact lens wearers have more problem with dry eyes; those with a history of eczema may find isotretinoin aggravates it; fair skinned people burn more easily; sportsmen may have more problems with muscles and joints aching.

If the side effects are troublesome, they will be easier to cope with on a lower dose of isotretinoin. They clear up completely within a few days to a month after the medication has been discontinued. Discuss your side effects with your dermatologist.

The majority of side effects are mucocutaneous i.e. they affect the skin and mucous membranes:

Acne flare
Acne flare early
in the course of
Dry lips on
Sunburn aggravated
by isotretinoin
Dermatitis due
to isotretinoin
Granulomas provoked by isotretinoin
Granulomas provoked by
isotretinoin in
a patient with acne
Staphylococcal impetigo
Staphylococcal impetigo
complicating a course
of isotretinoin
Infected nailfold
(paronychia) due
to isotretinoin
Adverse effects of isotretinoin

Other side effects of isotretinoin:

Monitoring isotretinoin

Most patients are advised to have blood tests before and on one or more occasions during isotretinoin treatment. Patients with certain serious health problems may be advised against taking isotretinoin, or may be treated with a lower dose than usual. Such health problems include severe liver or kidney disease, high blood fats, diabetes and depression.

The tests may include:

Your doctor may also arrange other tests.

Contraception and pregnancy in patients considering isotretinoin

Isotretinoin must not be taken in pregnancy because of a very high risk of serious growth abnormalities in the baby.

It should not be taken during breast-feeding as it enters the breast milk and might affect the baby.

You must tell your dermatologist if you think you may be pregnant before you start on isotretinoin. If you intend getting pregnant within the next six months or so, you should not take isotretinoin.

All females who could biologically have a child should take the following precautions during treatment with isotretinoin and for four weeks after the medication has been discontinued:

Isotretinoin has a very high chance of resulting in a spontaneous miscarriage or a severe birth deformity if a fetus is exposed to it during the first half of pregnancy. The deformities affect the growth of tissues developing at the time of exposure to the drug:

Males and females. Do not give blood while you are on isotretinoin or for a further four weeks after you have discontinued it, in case your blood is used for a pregnant woman.

Males. Isotretinoin has no effect on sperm or male fertility and has not been shown to cause birth defects in children fathered by men taking it. No specific contraceptive precautions are necessary for men.

Children. Children can take isotretinoin if necessary to control severe skin disease but prolonged courses are best avoided in case bone growth is slowed.

Slow responders to isotretinoin

Some patients with acne respond unexpectedly slowly and incompletely to isotretinoin. The reasons are thought to be:

Options available to slow responders include:

Isotretinoin in the treatment of acne relapses

At least fifty per cent of patients with acne are lucky enough to have a permanent cure after a single course of isotretinoin. Unfortunately, in some patients, acne recurs few months to a few years after the medication has been discontinued. Relapse is more common in females than in males.

If indicated, these patients may receive one or more further courses of isotretinoin. This may be at a similar dose and duration as before, or it may differ from previously.

A small number of people with particularly troublesome skin conditions require long term treatment with isotretinoin. With the exception of patients with skin cancers due to immunosuppressive medications eg organ transplant patients (who required 0.5 to 1mg/kg/day), generally only a small dose is required, such as 20 mg twice weekly. Another regime is to take 0.5 -1 mg/kg/day for one week out of every four weeks for a minimum of six monthly cycles. These regimes may be used for patients with:

Besides the worry about pregnancy in treated women, the main concern with long term treatment is that isotretinoin may have effects on the bones. Diffuse interstitial skeletal hyperostosis ("DISH"), a normal and common ageing process may be accelerated in those taking excessive doses of isotretinoin for long periods. The result can be seen on X-rays of the affected bones and includes spurs on the heel, knee, and spine. DISH may result in aching discomfort, which does not necessarily resolve when isotretinoin is discontinued.

Special precautions for pilots considering isotretinoin

Good night vision is important for airline pilots and those flying after dark. Night vision may be affected by isotretinoin. If you are a pilot, or planning an flying career, inform your dermatologist and find out your obligations from the national aviation authority. In New Zealand, this is the Civil Aviation Authority of New Zealand. Civil aviation licence holders, including Air Traffic Controllers, have an obligation under section 27 C of the Civil Aviation Act to ground self and report to CAA in case of any change in medical condition that may affect flight safety. CAA consider the use of Isotretinoin to be a change in medical condition. You are advised to contact CAA prior to commencing treatment with Isotretinoin, to discuss how this treatment may affect your flying privileges.

Related information


On DermNet NZ:

Other websites:

Author: Dr Amanda Oakley MBChB FRACP, Dept of Dermatology Waikato Hospital


The New Zealand approved datasheet is the official source of information for this prescription medicine, including approved uses and risk information. Check the New Zealand datasheet on the Medsafe website.

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If you have any concerns with your skin or its treatment, see a dermatologist for advice.