In a 62‑kg man on low‑dose isotretinoin (15‑25 mg daily) whose acne cleared after two months, should the medication be stopped or continued to achieve the cumulative target of 120‑150 mg/kg?

Should Isotretinoin Be Continued After Complete Clearance at 2 Months?

Yes, continue isotretinoin until the patient reaches the cumulative target dose of 120–150 mg/kg (7,440–9,300 mg total for this 62-kg man), even though his skin has already cleared. Early discontinuation at 2 months significantly increases relapse risk.

Rationale for Continuing Treatment

The American Academy of Dermatology explicitly recommends treating until the cumulative dose of 120–150 mg/kg is achieved to minimize relapse rates, regardless of when clinical clearance occurs. 1, 2 This recommendation is based on strong evidence showing that cumulative dose—not just clinical appearance—determines long-term remission.

Cumulative Dose Calculation for This Patient

For a 62-kg patient:

• Minimum target: 120 mg/kg = 7,440 mg total
• Maximum target: 150 mg/kg = 9,300 mg total 1, 2

At his current low-dose regimen (15–25 mg daily), he has accumulated only 900–1,500 mg after 2 months—far below the therapeutic threshold.

Evidence Supporting Continuation After Clearance

The FDA label and AAD guidelines state that if nodule count is reduced by >70% before completing 15–20 weeks, the drug may be discontinued, but this applies primarily to severe nodular acne at standard doses (0.5–1.0 mg/kg/day). 3 Your patient is on low-dose therapy for what appears to be moderate acne, where the evidence strongly favors completing the full cumulative dose. 1, 2

Research demonstrates that cumulative doses ≥220 mg/kg are associated with significantly lower relapse rates (26.9%) compared to lower cumulative doses (47.4% relapse rate). 4 Even the standard 120–150 mg/kg target represents a compromise between efficacy and treatment duration. 1

Specific Treatment Plan

Continue isotretinoin at the current low dose (15–25 mg daily) for an additional 8–10 months to reach the minimum cumulative target of 7,440 mg. 1, 2 This extended duration is the expected trade-off for low-dose therapy, which offers fewer mucocutaneous side effects but requires longer treatment. 5

Alternative: Dose Escalation

If the patient prefers a shorter treatment course, consider increasing to 0.5–1.0 mg/kg/day (31–62 mg daily), which would allow completion of the cumulative dose in the standard 15–20 week timeframe. 1, 2 However, this increases dose-dependent side effects like cheilitis, xerosis, and retinoid dermatitis. 1

Critical Guideline Recommendation

The AAD specifically advises continuing treatment for at least 2 months after achieving clear skin to reduce relapse frequency. 1 Your patient has just reached clearance at 2 months, meaning he should continue for a minimum of 2 additional months even by this conservative metric—and much longer to reach the cumulative dose target.

Common Pitfall to Avoid

Do not stop isotretinoin based solely on clinical appearance. The therapeutic endpoint is cumulative dose, not visible clearance. 1, 2 Premature discontinuation is the most common cause of relapse requiring retreatment. 4, 6

Monitoring During Extended Treatment

• Continue monthly pregnancy tests (if female with childbearing potential) 1, 3
• Monitor liver function tests and lipid panels monthly 1, 2
• Reassess for mood changes or depression at each visit 1, 2

Low-Dose Regimen Considerations

Low-dose isotretinoin (0.25–0.4 mg/kg/day) is explicitly endorsed by the AAD for moderate or treatment-resistant acne, with comparable long-term efficacy to standard dosing when continued for >6 months. 1, 2 The key is duration, not daily dose intensity. 5

Intermittent dosing (e.g., 1 week per month) is not recommended, as it produces significantly higher relapse rates compared to continuous daily dosing. 1, 2