Isotretinoin: Interactions with Other Medicines
Isotretinoin, still widely known by the old brand name Roaccutane, is the most effective treatment for severe acne. It is also one of the most tightly regulated medicines in the UK because of its effects on unborn babies and its long list of cautions. Interactions with other medicines and supplements are a frequent source of avoidable problems, especially among gym-goers who take several products at once.
Why isotretinoin needs special care
Isotretinoin is a retinoid, a molecule closely related to vitamin A. It shrinks sebaceous glands, reduces oil production, normalises the shedding of skin cells inside follicles and indirectly reduces the bacteria and inflammation that drive acne.
In the UK it can only be started by, or under the supervision of, a consultant dermatologist. Since 2023 the Medicines and Healthcare products Regulatory Agency (MHRA) has required additional safeguards, including independent agreement by two prescribers for patients under 18 and structured monitoring of mental health and sexual function.
The drug is a powerful teratogen: exposure during pregnancy carries a high risk of serious birth defects. Anyone who could become pregnant must follow the Pregnancy Prevention Programme, which includes highly effective contraception and regular pregnancy tests.
Because isotretinoin affects the liver, blood lipids, bones, skin barrier and possibly mood, other substances that act on the same systems can amplify its effects. That is the logic behind most of the interactions listed below.
Interactions to avoid
A small number of combinations are contraindicated or should be avoided because of clear and potentially serious risks.
- Tetracycline antibiotics (doxycycline, lymecycline, minocycline, oxytetracycline): both these antibiotics and isotretinoin can raise pressure inside the skull, a condition called benign intracranial hypertension. Warning signs include severe headache, nausea and visual disturbances.
- Vitamin A supplements: adding vitamin A to a retinoid increases the risk of hypervitaminosis A, with headaches, dry skin, liver effects and bone changes. Check multivitamins and some skin and eye supplements, which often contain retinol.
- Other oral retinoids: acitretin or alitretinoin should not be combined with isotretinoin.
Many patients have been on a tetracycline for months before being referred for isotretinoin, so the antibiotic must be stopped before the new treatment begins. Your dermatologist will advise on timing.
Contraception and St John's wort
For anyone in the Pregnancy Prevention Programme, interactions that reduce contraceptive reliability are the most important of all.
UK product information states that low-dose progestogen-only pills (the 'minipill') may not be adequate on their own during isotretinoin treatment. Highly effective, user-independent methods such as an implant or intrauterine device are preferred, sometimes combined with a barrier method.
St John's wort, a herbal remedy used for low mood, induces liver enzymes and can make hormonal contraceptives fail. It is sometimes taken without telling the prescriber, particularly as isotretinoin can be associated with mood changes. Breakthrough bleeding while using it may be a warning sign.
Certain anticonvulsants, antibiotics such as rifampicin and some HIV medicines also reduce contraceptive effectiveness. Always tell the dermatology team and your pharmacist about every product you take, including those bought online.
Medicines and products that need caution
Other combinations are not strictly forbidden but require monitoring or adjustment.
| Product | Possible effect | What to do |
|---|---|---|
| Systemic corticosteroids | Additive effects on bone and possibly mood | Use under medical supervision |
| Topical retinoids, benzoyl peroxide, peels | Severe skin irritation and dryness | Usually stopped; use gentle emollients |
| Alcohol | Raised triglycerides and liver strain | Keep intake low; tell your doctor |
| Other drugs that affect the liver | Additive hepatotoxicity | Liver tests as advised |
| Anabolic steroids and other unprescribed hormones | Worsened acne, lipids and liver tests | Disclose to the prescriber; seek medical advice |
| Waxing, laser and dermabrasion | Skin tearing and scarring | Avoid during and for months after treatment |
A significant proportion of acne in young men who train is linked to anabolic–androgenic steroid use. Isotretinoin does not cancel out the hormonal cause, and both agents can raise cholesterol and liver enzymes. A dermatologist needs to know about any such use to interpret blood tests correctly and plan treatment safely.
Oral supplements commonly used in the gym — whey protein, creatine, caffeine — have no known direct interaction with isotretinoin, but some 'skin', 'hair' or 'vision' formulas contain vitamin A and should be checked carefully.
Training, blood tests and side effects
Isotretinoin can raise creatine kinase, and intense exercise does the same. Landau and colleagues described patients with markedly elevated CK on isotretinoin, most commonly after strenuous activity. Rare cases of rhabdomyolysis have been reported, so new severe muscle pain, weakness or dark urine require urgent assessment.
Joint and back pain are common side effects. Many dermatologists suggest moderating very intense training during treatment, and it helps to tell the team if you play contact sport or lift heavily.
Blood monitoring usually includes liver function and fasting lipids at baseline and after about a month. A systematic review by Lee and colleagues found that clinically significant abnormalities are uncommon, which has led to less frequent testing in many services. Avoid hard exercise for a couple of days before tests to reduce false alarms.
Dry lips, skin and eyes are almost universal. Sun sensitivity increases, so use a high-factor sunscreen during outdoor training. Report any low mood, anxiety or changes in sexual function — the MHRA asks prescribers to check these at every review.
Editorial conclusions
Isotretinoin is highly effective but interacts with several medicines and supplements, most importantly tetracycline antibiotics, vitamin A and anything that weakens contraception.
Gym-goers should check multivitamins and skin supplements for vitamin A, be honest about any hormone use, and avoid strenuous sessions before blood tests.
The safest approach is to give your dermatologist and pharmacist a complete list of everything you take, and to ask before adding anything new during treatment.
Related topics on our site include steroid-related acne, how to read liver function tests and the effect of retinoids on blood lipids.
References
- Medicines and Healthcare products Regulatory Agency. Isotretinoin (Roaccutane): introduction of new safety measures, including additional oversight of the initiation of treatment for patients younger than 18 years. Drug Safety Update. 2023.
- Layton A. The use of isotretinoin in acne. Dermatoendocrinol. 2009;1(3):162–169.
- 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.
- Lee YH, Scharnitz TP, Muscat J, et al. Laboratory monitoring during isotretinoin therapy for acne: a systematic review and meta-analysis. JAMA Dermatol. 2016;152(1):35–44.
- Landau M, Mesterman R, Ophir J, et al. Clinical significance of markedly elevated serum creatine kinase levels in patients with acne on isotretinoin. Acta Derm Venereol. 2001;81(5):350–352.
- Brzezinski P, Borowska K, Chiriac A, Smigielski J. Adverse effects of isotretinoin: a large, retrospective review. Dermatol Ther. 2017;30(4):e12483.
