Bisphosphonate Therapy for HIV-Infected Adults With Decreased Bone Mineral Density

Inclusion Criteria: * HIV-infected * On stable antiretroviral regimen for at least 3 months * Able to walk * Lumbar spine or total hip BMD T-score at least 1.5 SD and no more than 3.5 SD below the mean BMD * No prevalent fractures at entry OR 1 prevalent vertebral fracture that has been asymptomatic during the last 2 years prior to study entry * HIV viral load of less than 5000 copies/ml within the 2 months prior to study entry * CD4 count of more than 100 cells/mm3 within the 2 months prior to study entry * Willing to use acceptable forms of contraception during the study period and for 6 months after study completion. Participants who are female and postmenopausal will be required to take hormone replacement therapy during this study. Exclusion Criteria: * Prior treatment with bisphosphonates or fluoride * Use of supraphysiologic systemic estrogen/androgen therapy or corticosteroid therapy within the 3 months prior to study entry. Participants who have taken hormone replacement therapy are not excluded. * Significant liver or kidney disease * Hemoglobin less than 8 g/dL * Serum calcium less than 8 mg/dL * Laboratory evidence of low levels of estrogens or androgens * Laboratory evidence of overactive parathyroid glands * History of thyroid, parathyroid, or other endocrinologic disorder known to affect bone * Current use of any therapy known to affect bone * Current or history of cancer or chemotherapy * Current or history of radiotherapy to the jaw * Current osteomyelitis of the jaw or ongoing dental infection * Recent tooth extraction or major dental procedure within 3 weeks of study entry * Pregnancy or breastfeeding