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Isotretinoin
Isotretinoin is an oral retinoid that shrinks the sebaceous glands and changes the course of acne — the only treatment that can bring long remission — but it is highly teratogenic, so it is given only within a strict pregnancy prevention programme and with laboratory monitoring.
Why it matters in the exam
The exam shows a teenage girl with scarring nodulocystic acne that has not responded to oral antibiotics for 3 months, and asks for the next treatment and what is mandatory before it: two methods of contraception or one highly effective method, a pregnancy test before treatment and every month, and lipid and liver tests at baseline and after about one month. Side effects are also asked: dry lips (the most common, in almost all patients), dry skin and eyes, myalgia, raised triglycerides and liver enzymes, photosensitivity, intracranial hypertension when combined with tetracyclines — so the combination is forbidden — and mood changes, which require active questioning about depression and suicidal thoughts at every visit. Remember the dose — 0.5–1 mg/kg/day to a cumulative dose of 120–150 mg/kg — the need to wait one month after finishing before pregnancy, the initial flare of acne at the start of treatment, and the ban on blood donation during treatment. A lower dose over a longer time is acceptable in patients with side effects.
Key points
- Isotretinoin is an oral retinoid that shrinks the sebaceous glands and changes the course of acne.
- It suits nodular, scarring or resistant acne, at 0.5–1 mg/kg/day to a cumulative dose of 120–150 mg/kg.
- The drug is highly teratogenic and requires two contraceptive methods, a monthly pregnancy test and a one-month wait after finishing.
- Lipids and liver tests are checked at baseline and after about one month, and mood is asked about at every visit.
- Tetracyclines must not be combined because of the risk of intracranial hypertension.
Summary table
| Aspect | Detail | Meaning | Action |
|---|---|---|---|
| Indication | Nodular or cystic acne, scarring acne, acne resistant to earlier treatment | The only treatment that changes the course of the disease | Refer to a dermatologist |
| Dose | 0.5–1 mg/kg/day, cumulative dose 120–150 mg/kg | Cumulative dose reduces relapse | Take with fatty food |
| Teratogenicity | Brain, heart, facial and ear malformations; miscarriage | Strict pregnancy prevention | Two contraceptive methods, monthly pregnancy test, one month wait after finishing |
| Laboratory | Raised triglycerides and liver enzymes | Pancreatitis risk with very high triglycerides | Lipids and liver tests at baseline and after about one month |
| Clinical side effects | Dry lips, skin and eyes; myalgia; mood; intracranial hypertension | Intracranial hypertension with tetracyclines | Do not combine with tetracyclines; ask about mood at every visit |
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Sources
- AAD guidelines of care for the management of acne vulgaris, 2024 — Isotretinoin
- European evidence-based (S3) guideline for the treatment of acne (EDF), 2016 — Systemic isotretinoin
- Israeli Ministry of Health pregnancy prevention programme for isotretinoin, 2023 — Prescribing requirements
Sources are given for further reading; the text is written afresh and not copied from them.
Reviewed by the Examqo AI Professor · 2026-11-06. The text may contain errors; when in doubt, check the source.