Isotretinoin
Isotretinoin is an oral retinoid (13-cis-retinoic acid) that produces durable remission of severe, treatment-resistant acne. In the PED context it is used for the severe androgen-driven acne that high-dose steroids can cause. It is highly effective but carries substantial risks: it is powerfully teratogenic, raises triglycerides and liver enzymes, dries skin and mucosa, and has a debated association with mood disturbance.
01 Overview
Isotretinoin shrinks sebaceous glands and dramatically reduces sebum production, normalises follicular keratinisation and has anti-inflammatory effects, which is why a single course often clears severe nodulocystic acne long-term. Because steroid use can drive severe acne through increased sebum and androgen activity, isotretinoin is used when topical and antibiotic treatment fails.
The safety profile demands respect. It is one of the most teratogenic drugs in common use — pregnancy must be strictly avoided — which is why it is dispensed under monitored programmes. It commonly raises triglycerides and liver transaminases (relevant to already lipid-stressed steroid users), causes marked dryness of skin, lips and eyes, and has a controversial association with depression and, rarely, suicidality that warrants mood monitoring.
02 Mechanism
Retinoid that reduces sebaceous gland size and sebum output, normalises follicular keratinisation and is anti-inflammatory, addressing the drivers of severe acne.
03 Dosing
| Tier | Dose | Route | Notes |
|---|---|---|---|
| Severe acne (low) | 20–40 mg/day | Oral | Lower daily dosing is often used to limit side effects, extending course length. |
| Severe acne (label, weight-based) | 40–80 mg/day | Oral | Roughly 0.5-1 mg/kg/day; courses target a cumulative dose of ~120-150 mg/kg. |
04 Effects
| Effect | Magnitude | Evidence | |
|---|---|---|---|
| Durable acne clearanceOften clears severe nodulocystic acne with lasting remission after a single course. | long-term remission | Clinical | |
| Reduced sebum productionShrinks sebaceous glands, reducing oily skin — directly relevant to androgen-driven acne. | marked reduction | Clinical |
05 Side effects
| Effect | Severity | Frequency | Evidence | Countermeasures |
|---|---|---|---|---|
| TeratogenicityCauses severe birth defects; pregnancy during treatment must be absolutely avoided. | Life-threatening | Certain if pregnant | Clinical | |
| Raised triglycerides / liver enzymesElevated triglycerides and transaminases, compounding lipid strain already present in steroid users. | Moderate | Common | Clinical | |
| Mucocutaneous drynessDry, chapped lips, dry skin, nosebleeds and dry eyes. | Mild | Near-universal | Clinical | |
| Mood disturbanceReports of depression and, rarely, suicidal ideation; a causal link is debated but monitoring is advised. | Severe | Uncommon and debated | Disputed |