Carbamazepine* Disturbed bone mineral metabolism: first report

Although carbamazepine has previously been shown to decrease serum calcium and serum alkaline phosphatase values, this study is the first report of disturbances of bone mineral metabolism. 21 epileptic patients (age range 18-65 years) on a mean daily dose 01 505mg carbamazepine for 15-168 months, were investigated. A control group of age- and sex-matched healthy subjects was used.

Changes suggestive of carbamazepine interference with vit D metabolism, with possible subsequent development of osteomalacia (probably a result of faster conversion of viI D to inactive metabolites by hepatic enzyme induction) were demonstrated. 14% of patients had hypocalcaemia, 5% had hypophosphataemia, and 19% raised serum alkaline phosphatase. Concentrations of serum-25·hydroxy­vilamin-D were lower and the amount of trabecular resorption surfaces grealer in treated patients than in controls. 1 t % of patients had increased osteoid volumes suggesting osteomalacia. More studies are needed to differentiate the effects of carbamazepine on bones from those of phenytoin. phenobarbital. and primidone.

Hoikha. V et al. Acta NeuroiogiCa ScandinavH::a 70: 77 (No 2. 1984)

0157-7271/84/1215-0005/0$01.00/0 @ ADIS Press Reactions 15 Dec 1984 5