ISOTRETINOIN THERAPY IN ACNE VULGARIS: A 10-YEAR RETROSPECTIVE STUDY IN SINGAPORE

Background. The use of isotretinoin, a first generation synthetic retinoid, in the treatment of patients with severe acne vulgaris was a major therapeutic advance in dermatology. This 10–year retrospective study reviews the effectiveness of isotretinoin in patients with acne vulgaris seen in a skin clinic in Singapore. Methods. The case records of 250 cases of severe inflammatory and nodulocystic acne treated with isotretinoin were analyzed with reference to the demographic data, response to isotretinoin, dosage and cost of isotretinoin used, adverse effects, clinical follow-up, and relapse. Results. Two hundred and fifty patients, 171 men (68.4%) and 79 women (31.6%), with different types and grades of acne vulgaris were studied. The dose of isotretinoin used ranged from 0.33 to 1.0 mg/kg/day (median 0.5 mg/kg/day) for a period ranging from 1 to 12 months (median 4 months). Response was excellent in 127 (50.8%) patients, good in 86 (34.4%), fair in 30 (12.0%) and poor in 7 (2.8%). Relapse occurred in 14 (5.6%) patients over a 6–month follow-up period. Adverse effects were noted in 140 (56.0%) patients and were mild in most cases. Eighteen (7.2%) patients had to discontinue the drug due to significant side effects. Conclusion. This study confirms that isotretinoin is very effective for severe acne, and complete remission can be induced in more than 90% of cases even with lower dosage regimens. Significant clinical improvement can be achieved with the use of lower doses (mean 0.5 mg/kg/day) for an average of 4 months of treatment with lower risk of adverse effects.