01Purpose and principlesWhat the treatment does and how it fits into care.
Isotretinoin suppresses sebaceous activity, normalises follicular keratinisation and produces durable remission in appropriately selected severe acne. Its benefits must be balanced against predictable mucocutaneous effects, laboratory abnormalities, possible psychiatric and sexual adverse effects and extreme teratogenicity. It is therefore initiated by a Lead Prescriber who understands systemic retinoids and monitoring, after documented adequate standard treatment or an equally compelling high-risk presentation.
Current UK safeguards changed in January 2026. Agreement from a second independent prescriber is no longer a regulatory requirement for people under 18. Instead, the revised Acknowledgement of Risk Form confirms indication, lack of another appropriate effective treatment, understanding of harms and the option to seek a second opinion; services participate in audit and patients are directed to the authorised information video. Existing mental-health, sexual-function and pregnancy-prevention safeguards remain.
Consent is a continuing process, not a signature. Discuss expected cheilitis and dryness, sun sensitivity, musculoskeletal symptoms, night-vision change, blood donation, cosmetic procedures, interactions, pregnancy rules and routes for urgent advice. Use the patient’s name and anatomy rather than assumptions about gender to establish pregnancy potential. A first consultation should be in person; later consultations and supervised pregnancy testing can be remote when the MHRA conditions and clinical circumstances allow.
Practical prevention reduces predictable harm. Supply a bland lip emollient and moisturiser plan from the start, recommend sunscreen and lubricating eye drops when appropriate, and review contact-lens tolerance and night driving. Avoid waxing, dermabrasion, tattoos and other traumatic skin procedures during treatment and for the interval specified by current patient information because fragility and abnormal repair can persist. Heavy exercise does not have to stop routinely, but new severe muscle pain or weakness deserves creatine-kinase assessment and dose review. Alcohol intake, obesity, diabetes and lipid history influence triglyceride monitoring and counselling without automatically excluding effective treatment.
Key points
- Consider isotretinoin from age 12 for severe acne resistant to adequate systemic antibacterial and topical therapy, including nodulocystic acne, conglobata, fulminans or disease at risk of permanent scarring.
- A Lead Prescriber with systemic-retinoid expertise initiates treatment and confirms that no other appropriate effective option remains; every patient completes the current Acknowledgement of Risk process.
- From January 2026, UK patients under 18 no longer require agreement from a second independent prescriber; enhanced risk documentation, patient information and clinical audit replaced that regulatory step.
- Assess mental health with a patient-reported outcome measure and ask about sexual function before treatment, then revisit both at every follow-up.
- Anyone who can become pregnant enters the Pregnancy Prevention Programme unless robustly established criteria show no pregnancy potential.
- Effective contraception starts at least one month before treatment, continues throughout and for one month after stopping; pregnancy testing follows current programme and product requirements.
- A usual starting dose is 0.5 mg/kg/day with food, adjusted within approximately 0.5–1 mg/kg/day; a lower dose can be used when adverse-effect risk or intolerance requires it.
- Do not combine isotretinoin with tetracyclines or vitamin A supplements, do not donate blood during treatment or for one month afterwards, and never share capsules.
02Indications, selection and cautionsWho may benefit, who needs urgent treatment and important alternatives.
Deep nodules, conglobate disease, fulminant inflammation or ongoing permanent scarring after adequate oral antibacterial and topical treatment supports specialist isotretinoin assessment.
Dry lips, dry skin, nasal dryness, eye irritation and photosensitivity are common dose-related effects that need anticipatory emollient, lip and eye care.
Persistent severe headache, nausea, diplopia, pulsatile tinnitus or visual obscurations demands urgent assessment, especially after inadvertent tetracycline co-exposure.
New depression, agitation, emotional blunting, anxiety, psychotic symptoms or suicidal thoughts require direct safety assessment and rapid coordination with the Lead Prescriber.
Reduced libido, erectile difficulty, genital sensory change, vaginal dryness or orgasmic difficulty should be asked about confidentially and acted on without embarrassment or dismissal.
A missed period, contraception failure, unprotected intercourse or positive test during therapy or within one month after stopping triggers immediate cessation and specialist contact.
03Assessment before treatmentTests and checks that guide safe selection.
Read from the initial assessment onwards. Tests may run in parallel in urgent care; first-line, preferred, confirmatory, definitive and gold-standard labels appear only when the chapter explicitly states them.
- 01
Documented indication and treatment historyFirst step - Why
- Confirm severe, scarring-risk or resistant acne and absence of another appropriate effective treatment.
- Interpretation and limitations
- Record drug, dose, duration, adherence and response rather than the phrase previous antibiotics; inadequate use should be corrected unless delay risks further irreversible scarring.
- 02
Pregnancy-potential and contraception assessment - Why
- Determine entry to the Pregnancy Prevention Programme and agree a feasible prevention plan.
- Interpretation and limitations
- Base the decision on reproductive potential and current circumstances, not gender markers; document why programme requirements apply or why pregnancy potential is absent.
- 03
Medically supervised pregnancy testing - Why
- Exclude pregnancy before exposure and detect it during and after treatment according to current programme rules.
- Interpretation and limitations
- Time and document tests in relation to treatment and contraception; remote testing is permissible only with suitable oversight ensuring correct identity, performance and result review.
- 04
Mental-health patient-reported outcome measure - Why
- Create an objective baseline and support direct clinical discussion before prescribing.
- Interpretation and limitations
- A score informs but never substitutes for interview, risk assessment and collateral information where consented; pre-existing illness is not an automatic exclusion but needs a safe plan.
- 05
Baseline lipids and liver function - Why
- Identify important abnormalities before dose exposure and provide a comparator for treatment monitoring.
- Interpretation and limitations
- Interpret triglycerides and transaminases with fasting status, alcohol, metabolic risk and symptoms; monitoring frequency is individualised rather than replaced by one normal result.
- 06
Additional targeted baseline tests - Why
- Assess comorbidity or symptoms relevant to safe systemic retinoid use.
- Interpretation and limitations
- FBC, glucose, creatine kinase or other testing is selected for clinical risk, concomitant medicines and symptoms rather than ordered as an unvarying panel.
04Treatment approachPreparation, options, escalation and aftercare.
01Specialist initiationConfirm indication and informed choiceFirst stepSevere acne has resisted adequate topical and systemic antibacterial treatment or is creating a substantial permanent-scarring risk.+
- 1The Lead Prescriber reviews diagnosis, prior treatment, scarring, alternatives, medicines, physical risks, mental health, sexual function and pregnancy potential at an in-person first appointment.
- 2Provide accessible written and video information, discuss benefits and uncertainties, complete the updated Acknowledgement of Risk Form and offer the option of a second opinion.
- 3Complete baseline tests and the Pregnancy Prevention Programme where applicable, then prescribe the product-specific weight-based regimen with clear contacts for adverse effects.
02Pregnancy preventionMaintain a closed safety loopThe patient can become pregnant and isotretinoin is being considered, taken or was stopped less than one month ago.+
- 1Agree effective contraception for at least one month before treatment, throughout therapy and one month afterwards, or document medically established abstinence in the programme context.
- 2Undertake medically supervised pregnancy tests at the required times, coordinate prescription and dispensing requirements, and revisit adherence or contraceptive difficulty without judgement.
- 3If pregnancy occurs or is suspected, stop isotretinoin immediately and arrange urgent specialist, obstetric and teratology advice while maintaining confidentiality and support.
03Each follow-upReview benefit, toxicity and consentA patient returns during an isotretinoin course, whether in person or through an appropriate remote review.+
- 1Ask about acne activity, dryness, headache, vision, abdominal and musculoskeletal symptoms, mood and self-harm, and sexual function; repeat the objective mental-health measure.
- 2Review pregnancy testing and contraception when relevant, adherence, all new medicines, alcohol, supplements, blood donation and laboratory results; specifically exclude tetracyclines and vitamin A.
- 3Adjust the daily dose to response and adverse effects, document ongoing informed agreement and provide urgent routes for pregnancy, neurological, psychiatric or severe systemic symptoms.
05Regimens, contraindications and interactionsTreatment details and the circumstances that modify them.
Isotretinoin capsules
Start around 0.5 mg/kg/day with food; most patients use 0.5–1 mg/kg/day adjusted to response and toxicity. Aim for a cumulative 120–150 mg/kg, but consider earlier cessation after four to eight weeks without new lesions.Absolutely contraindicated in pregnancy and breastfeeding; apply the Pregnancy Prevention Programme, avoid tetracyclines and vitamin A, monitor mental health, sexual function, liver and lipids, and follow the current SmPC and MHRA materials.
06Complications, monitoring and follow-upAdverse effects, response and longer-term review.
- At every follow-up, repeat direct mental-health and sexual-function questions and an objective mental-health patient-reported outcome measure; create an urgent safety plan for concerning findings.
- Track new inflammatory lesions, scarring, daily and cumulative dose, missed doses, cheilitis, dermatitis, eye and nasal symptoms and functional adverse effects.
- Review triglycerides and liver tests after treatment begins and thereafter according to results, dose, comorbidity and product information; investigate symptoms rather than waiting for routine bloods.
- For patients in the Pregnancy Prevention Programme, document contraception and supervised testing at each required point and for one month after treatment ends.
- At completion, reinforce one-month contraception and blood-donation restrictions, medicine return or safe disposal, non-sharing and advice on skin procedures and persistent adverse effects.
- Submit suspected adverse reactions to the MHRA Yellow Card scheme with medicine, dose, timing, co-exposures and relevant medical history.
07Special situationsVariants, exceptions and circumstances that change the usual approach.
The 2026 rule changed
Under-18 initiation no longer legally requires a second prescriber, but expertise, indication confirmation, risk acknowledgement, monitoring and the option of a second opinion remain.
A questionnaire starts conversation
A normal mental-health score cannot overrule a patient or relative describing a marked and dangerous change.
Ask everyone about sexual function
Neutral, confidential questions before treatment and at follow-up make adverse effects easier to disclose and properly document.
Food matters for absorption
Licensed isotretinoin capsules are taken with food; inconsistent administration can produce variable exposure and a misleading dose-response picture.
Clearance can alter the endpoint
Although 120–150 mg/kg is a conventional cumulative target, NICE allows earlier stopping after sustained absence of new lesions for four to eight weeks.
08Common pitfallsFrequent interpretation and management errors.
- 01
Repeating the obsolete two-prescriber requirement for patients under 18 after the January 2026 MHRA change.
- 02
Treating a completed risk form as a replacement for accessible counselling, understanding and continuing consent.
- 03
Asking about pregnancy potential from an administrative sex marker rather than a private, respectful reproductive history.
- 04
Monitoring liver tests while omitting direct questions about suicidal thoughts, mood change or sexual function.
- 05
Allowing a tetracycline to remain on the shared medication list when specialist isotretinoin begins.
- 06
Advising a patient to donate blood or share unused capsules because treatment has already been dispensed.