Who Should Not Take Isotretinoin

Isotretinoin is the most effective treatment available for severe acne and has cleared the skin of millions of people. It is also one of the most tightly regulated medicines in dermatology. In the UK, it can only be started by a consultant dermatologist, and the MHRA strengthened safety measures again in 2023. Understanding who should not take it — and who needs extra caution — is central to its safe use. Our editorial team sets out the main contraindications and precautions.

What isotretinoin is and why it is restricted

Isotretinoin is a retinoid, a derivative of vitamin A. Taken by mouth, it shrinks sebaceous glands, dramatically reduces sebum production, normalises the shedding of skin cells inside follicles and has anti-inflammatory effects. It is the only acne treatment that targets all the main processes behind the disease and can produce long-lasting remission.

It is licensed in the UK for severe forms of acne, such as nodular or conglobate acne, or acne at risk of permanent scarring, which has not responded to adequate courses of standard therapy including oral antibiotics and topical treatment.

The restrictions arise from two main concerns. First, isotretinoin is a potent teratogen: exposure during pregnancy carries a high risk of serious birth defects. Second, there have been long-standing reports of psychiatric and sexual side effects, which prompted a Commission on Human Medicines review and new measures in 2023.

Under current MHRA requirements, patients under 18 need agreement from two independent prescribers before starting, and all patients should be assessed for mental health and sexual function before and during treatment.

Absolute contraindications

According to the UK summary of product characteristics, isotretinoin must not be used in the following situations:

• pregnancy — and in anyone able to become pregnant unless all conditions of the Pregnancy Prevention Programme are met;
• breastfeeding, as retinoids pass into breast milk;
• hepatic insufficiency (significant liver disease);
• excessively elevated blood lipids;
• hypervitaminosis A or concurrent vitamin A supplements;
• concurrent tetracycline antibiotics, because both can raise intracranial pressure;
• hypersensitivity to isotretinoin or excipients — some capsule brands contain soya oil and, in some products, peanut-derived ingredients.

These are firm rules, not preferences. A dermatologist will check for each before prescribing.

The tetracycline point is especially relevant because many people arrive at isotretinoin after courses of lymecycline or doxycycline. The antibiotic must be stopped before isotretinoin begins.

The Pregnancy Prevention Programme

Because even a short exposure in early pregnancy can cause severe malformations of the face, heart and nervous system, as well as miscarriage, isotretinoin is subject to a strict Pregnancy Prevention Programme for anyone who could become pregnant.

Anyone unable or unwilling to follow these steps should not take isotretinoin. Blood donation is also prohibited during treatment and for a month afterwards, to avoid exposing a pregnant recipient.

Male patients are not subject to the same contraception requirements, as the amount in semen is considered too small to pose a risk, but they must never share their medicine.

Conditions that need special caution

Some groups can take isotretinoin but require careful assessment and closer monitoring:

Mental health conditions. People with current or previous depression, anxiety, self-harm or suicidal thoughts need a thorough assessment and close follow-up. Whether isotretinoin causes depression remains debated — acne itself harms mental health — but regulators require vigilance, and patients and families should report mood changes immediately.

Diabetes, obesity, alcohol excess and lipid disorders. Isotretinoin can raise triglycerides and cholesterol and affect glucose control. Baseline and follow-up lipid and liver tests are standard.

Inflammatory bowel disease, kidney impairment and dry eye conditions also warrant caution. Contact lens wearers may struggle with dry eyes, and night vision can decrease in some people.

Athletes, training and practical considerations

Isotretinoin is not on the World Anti-Doping Agency's Prohibited List, so athletes can use it without a Therapeutic Use Exemption. However, it does have specific implications for people who train hard.

Muscle and joint pain are common side effects, and isotretinoin can raise creatine kinase, especially after intense exercise. Very high CK levels can make blood test interpretation difficult and, rarely, rhabdomyolysis has been reported. Athletes should tell their dermatologist about their training load, and avoid scheduling blood tests immediately after heavy sessions.

Dry skin, chapped lips and nosebleeds are almost universal. Increased sun sensitivity matters for outdoor sports, so high-factor sunscreen and lip balm are essential. Waxing, dermabrasion and laser treatments should be avoided during and for some months after treatment because of fragile skin.

Finally, anyone using anabolic steroids should be aware that combining them with isotretinoin adds to liver and lipid strain, and that continuing androgen use undermines the treatment. Honesty with the prescriber is essential for safety. Isotretinoin must only ever be obtained through a dermatologist, never from unregulated online sources.

Editorial team's conclusions

Isotretinoin is highly effective but unsuitable for some people. It must not be used in pregnancy, while breastfeeding, with significant liver disease, very high lipids, excess vitamin A or tetracyclines. Anyone who could become pregnant must follow the Pregnancy Prevention Programme, and people with mental health conditions need careful assessment. Under UK rules, treatment is started and supervised only by a consultant dermatologist.

You may also find it useful to read about acne in athletes and its links with performance drugs, how to interpret creatine kinase results after training, and how anabolic steroids affect blood lipids.

References

1. Medicines and Healthcare products Regulatory Agency. Isotretinoin: introduction of new safety measures, including additional oversight of the initiation of treatment for patients under 18 years of age. Drug Safety Update. 2023.
2. Layton A. The use of isotretinoin in acne. Dermatoendocrinol. 2009;1(3):162–169.
3. Zaenglein AL, Pathy AL, Schlosser BJ, et al. Guidelines of care for the management of acne vulgaris. J Am Acad Dermatol. 2016;74(5):945–973.
4. Lammer EJ, Chen DT, Hoar RM, et al. Retinoic acid embryopathy. N Engl J Med. 1985;313(14):837–841.
5. National Institute for Health and Care Excellence. Acne vulgaris: management (NICE guideline NG198). London: NICE; 2021.