Changes in laboratory variables induced by isotretinoin treatment of acne

During a trial of isotretinoin (0.5 mg/kg body weight/day for 3 months) in 90 patients with severe acne, the leucocyte (WBC) count, and particularly the number of neutrophils, decreased significantly. In patients with a good response the mean WBC count fell by 24% and the neutrophils by 33%, whereas in those with a poor response these variables decreased by 8% and 14%, respectively. The serum ALAT, ASAT, cholesterol and triglyceride levels increased significantly. Patients with a poor response (n = 35) received a higher dosage (0.75 mg/kg) for an additional 3 months, and during this period there was a further decrease in the WBC and neutrophil counts and an increase in the triglyceride level. In the other patients, who initially responded well, the dosage was decreased to 0.1 or 0 mg/kg during the second 3-month period, which resulted in reversion of the laboratory variables to the pre-treatment levels. The observed changes were clearly both dose-dependent and reversible.