Do Vitamin B12 Levels Need to be Evaluated in FMF Cases Having Long Term Colchicine Treatment?

Background: Colchicine used in the treatment of FMF inhibits absorption of Vitamin B12. Objective: To evaluate serum vitamin B12 levels in cases with Familial Mediterranean Fever (FMF) receiving long term colchicine therapy. Method: Serum vitamin B12 and folic acid levels, and full blood count of 70 patients with FMF that received more than 5 years of colchicine therapy were evaluated. The results were compared with 80 patients that received less than 5 years of colchicine therapy and 70 healthy children. Results: Mean age of the patient group was 15.5±2.45 years; and the mean age of the patients that received less than 5 years of colchicine therapy was 10.24±4.02 years. Mean vitamin B12 level of the patients that received more than 5 years of colchicine therapy (208.37±40.57 pg/ml) was significantly lower than the patients that received less than 5 years of colchicine therapy (390.77±124.19) and the control group (478.31±135.76) (p=0.0001, p<0.005). MCV was significantly lower in patients who received more than 5 years of colchicine therapy (p=0.38, p<0.005). However, MCV was in normal limits in all three groups. There was no significant difference between the groups in terms of folic acid, hemoglobin and hematocrit values. Conclusion: Long term colchicine therapy may decrease serum vitamin B12 levels, but does not lead to megaloblastic anemia. Even if serum vitamin B12 levels are sufficient for 3-5 years in cases where there is no other illness, we must consider that neurological findings can appear before anemia and have to evaluate serum vitamin B12 levels at certain intervals in patients under long term colchicine therapy.