Alendronic acid for antipsychotic-related osteopenia

Is antipsychotic treatment linked to low bone mineral density and osteoporosis? A review of the evidence and the clinical implications

OBJECTIVE

Osteoporosis is increasingly common worldwide and there is a growing concern that the long-term use of antipsychotic medications increases the risk of this disorder. In this review, we consider whether antipsychotics may contribute to the development of osteoporosis through reductions in bone mineral density, discuss the possible mechanisms involved and consider the clinical implications of such a relationship.

METHODS

We searched the literature for studies in this area published between 1966 and 2010 using the Medline and PubMed databases, supplemented by hand searches of retrieved reports.

RESULTS

The available data indicate that statistically significant reductions in bone mineral density are frequently seen in patients prescribed with antipsychotic medications and suggest that there is a higher incidence of clinically significant reductions compared with the normal population.

CONCLUSIONS

Clinicians should be aware for the potential negative effects of antipsychotic medications on bone mineral density, particularly in patients with additional risk factors for osteoporosis. Recommendations regarding routine monitoring of bone mineral density for patients prescribed antipsychotic medications cannot be made on the basis of existing evidence, and more research is required.

The antipsychotics haloperidol and chlorpromazine increase bone metabolism and induce osteopenia in female rats

The main objective of this study was to evaluate the effects of the antipsychotic drugs haloperidol (HAL) and chlorpromazine (CPZ) on bone mineral density (BMD) in female rats and to examine the relationship between the effects on bone and reproductive organs or hormone concentrations. Female rats were orally administered HAL (2 or 10 mg/kg) or CPZ (25 or 50 mg/kg) once daily (7 days/week) for 6 months resulting in a significant increase in prolactin. Hyperprolactinemia resulted in enlarged corpora lutea in the ovary, because prolactin has a luteotropic activity. Thus, atrophy in the uterus, epithelial mucification in the vagina and continuous diestrus stages were observed. These events in the reproductive organs induced a decrease in estradiol, elevation of biochemical markers of bone metabolism, significant reductions of BMD in trabecular bone of the femur and decreased trabecular bone in the femur. The bone loss is associated with an increase in bone resorption due to decreased estradiol derived from the luteotropic activity of prolactin. The mechanism of dopamine blockers to induce bone loss in female rats is considered to be rodent specific because the luteotropic effects of prolactin are confined primarily to rodents. Also, it appears that chronic hyperprolactinemia and maintained corpora lutea leading to bone loss are commonly inducible in female rats receiving long-term treatment with antipsychotic drugs possessing dopamine D2 receptor antagonist activity.