Oral isotretinoin is widely recognized as the most effective treatment for moderate to severe acne, and its side effects are mainly dependent on the dosage. Low-dose isotretinoin, administered at 0.5 mg/kg/day for 1 week, every 4 weeks over a 6-month period, has shown effectiveness comparable to high or optimal doses. 

A systematic review aimed to summarize the findings of clinical trials on low-dose isotretinoin use in treating acne. The study considered the indications, dosage, prescription protocol, effectiveness, side effects, patient satisfaction, recurrence rate and follow-up period.

Here, relevant articles were searched through various databases like Cochrane, Google Scholar, Science Direct, PubMed and Medline. Out of a total of 460 electronically searched articles, 382 were excluded based on predetermined criteria. Among the exclusions, 4 articles were non-English and 2 were published before 1980. The full text of the remaining 72 articles was reviewed, and ultimately, 15 documents met the inclusion criteria for this systematic review.

The results depicted that the standard isotretinoin dose typically ranges from 0.5 to 1 mg/kg/day for a duration of 4 months, with a cumulative dose of 120-140 mg/kg/day. However, daily doses in the range of 0.1 to 0.3 mg/kg can be recommended for periods longer than 6 months, as they have been associated with fewer side effects and are more cost-effective. Combining low-dose isotretinoin with other medications may enhance its effectiveness in acne treatment.

Overall, the systematic review provides valuable insights into low-dose isotretinoin use, including its optimal dosage, duration and potential combination with other therapies. The findings shed light on the efficacy, side effects, patient satisfaction, recurrence rate and follow-up requirements with this treatment modality.

Source: Sadeghzadeh‐Bazargan A, Ghassemi M, Goodarzi A, Roohaninasab M, Najar Nobari N, Behrangi E. Systematic review of low-dose isotretinoin for treatment of acne vulgaris: focus on indication, dosage, regimen, efficacy, safety, satisfaction, and follow up, based on clinical studies. Dermatol Ther. 2021;34(1):e14438.