Educational draft · awaiting clinical reviewUse Rapid for revision, not patient-care decisions. Check current national and local guidance and the BNF or BNFC before acting.
Isotretinoin is highly teratogenic, and pregnancy during treatment or within one month after stopping creates a major risk of severe fetal malformation.
Action: Stop isotretinoin, arrange an urgent pregnancy test and contact the prescribing dermatology service immediately for coordinated obstetric and teratology counselling; do not make an isolated risk prediction.
Synopsis
Identify severe acne that merits consultant-dermatologist-led isotretinoin, apply the current 2026 UK risk-minimisation framework, prevent pregnancy exposure and monitor physical, mental-health and sexual adverse effects.
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.
Key red flags
Possible pregnancy, severe headache with visual change, suicidal thoughts, major mood change, new sexual dysfunction, severe abdominal pain, jaundice, blistering rash or anaphylaxis requires prompt medicine interruption or urgent specialist assessment according to severity.
Intracranial-pressure warning
Persistent severe headache, nausea, diplopia, pulsatile tinnitus or visual obscurations demands urgent assessment, especially after inadvertent tetracycline co-exposure.
Investigation priorities
01
Documented indication and treatment historyFirst step
Confirm severe, scarring-risk or resistant acne and absence of another appropriate effective treatment.
Management branches
Specialist initiationConfirm indication and informed choice
Severe acne has resisted adequate topical and systemic antibacterial treatment or is creating a substantial permanent-scarring risk.
The Lead Prescriber reviews diagnosis, prior treatment, scarring, alternatives, medicines, physical risks, mental health, sexual function and pregnancy potential at an in-person first appointment.
Provide accessible written and video information, discuss benefits and uncertainties, complete the updated Acknowledgement of Risk Form and offer the option of a second opinion.
Key medicines
Isotretinoin capsulesStart 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.
National guidance is shown before implementation-dependent detail. Typical adult dose examples remain subject to patient factors, contraindications and the live BNF or specialist protocol. Source check completed 27 Aug 2026; clinical approval remains outstanding.