[Studies on the usefulness of a long-term, high-dose treatment of methylcobalamin in patients with oligozoospermia].

Methylcobalamin (CH3-B12) was administrated in a dose of 6 mg per day (group A, 16 cases) or 12 mg per day (group B, 23 cases) for 16 weeks to patients with oligozoospermia. There was no difference between group A and group B regarding vitamin B12 concentrations in the serum or seminal fluid. CH3-B12 appeared to be transported to seminal fluid very efficiently. However, results from group A and group B did not differ with respect to this parameter. The efficacy rate for group A was 37.5% and that for group B was 39.1%. From these results, it was concluded that a long-term, high dose treatment of CH3-B12 was useful for the treatment of patients with oligozoospermia. Since the efficacy rates were not different between the two groups, 6 mg per day would be the recommended dose. Clinical adverse reactions were observed in one patient in each group. Drug-related laboratory adverse reactions were observed in only one patient in group B.