Elevated plasma homocysteine levels in patients on isotretinoin therapy for cystic acne

Background The use of Isotretinoin (Iso) for cystic acne (CA) therapy inclu des marked side-effects such as dyslipidemia, increased liver enzymes, and reduction of biotinidase activity. Moreover, Homocysteine (Hcy), an amino a cid, is metabolized in the liver requiring folate, vitamin B6, vitamin B12, and the activity of enzymes, i.e, cystathionine-beta -synthase. Increased blood levels of Hey are associated with premature occlusive vascular diseas e. Objective The aim of this study was the evaluation of Hey levels and the re sponsible vitamins for its metabolism in patients with CA on Iso treatment. Methods and Results Twenty-eight patients with CA were submitted to laborat ory examinations before (Value 1) and after (Value 2) 45 days on Iso (0.5 m g/kg/24 h) therapy. Blood levels of Hey and vitamin B6 were evaluated by HP LC methods, and folate and vitamin B12 using a commercial Kit. Hey levels ( Value 1 = 7.86 +/- 1.6 mu mol/L; Value 2 = 13.65 +/- 3.3 mu mol/L; P< 0.001 ) were statistically significantly increased in patients on treatment. Vita mins were unaltered, and lipids and liver enzymes increased. Significant co rrelation between Hey levels, vitamins, and liver enzymes was found. Methio nine loading tests performed in nine patient-volunteers showed an abnormal response post-treatment. Conclusions It is suggested that the elevated Hcy levels in patients after 45 days on Iso therapy could be due either to the 'inhibition' of cystathio nine-<beta>-synthase by the drug and/or their liver dysfunction. Daily vita min supplementation along with frequent evaluations of Hey blood levels are recommended for the prevention of a premature occlusive vascular disease.