Sustained-release sodium fluoride in the management of established postmenopausal osteoporosis

Osteoporosis and trace elements--an overview

More than 200 million people are affected by osteoporosis worldwide, as estimated by 2 million annual hip fractures and other debilitating bone fractures (vertebrae compression and Colles' fractures). Osteoporosis is a multi-factorial disease with potential contributions from genetic, endocrine functional, exercise related and nutritional factors. Of particular considerations are calcium (Ca) status, vitamin D, fluoride, magnesium and other trace elements. Several trace elements such as zinc and copper are essential for normal development of the skeleton in humans and animals. Fluoride accumulates in new bone and results in a net gain in bone mass, but may be associated with a tissue of poor quality. Aluminum induces impairment of bone formation. Gallium and cadmium suppresses bone turnover. However, exact involvements of the trace elements in osteoporosis have not yet been fully clarified. Numerous investigators have evaluated the role of medications and supplementations with minerals and trace substances to reverse the progression of this disease. Although bisphosphonates are still the drugs of choice, low-dosed fluoride and strontium salts have shown promise for the future.

Comparative safety of bone remodeling agents with a focus on osteoporosis therapies

This article reviews the different treatments currently available for osteoporosis and examines the benefits and adverse events that are associated with each. While emphasizing safety considerations, this review summarizes the following treatments for osteoporosis: calcium supplements, fluoride, hormone replacement therapy, raloxifene, bisphosphonates, salmon calcitonin, and calcitriol. Before prescribing any of these agents, the clinician should review the risk/benefit profile of each drug in the context of the individual patient's history, concomitant diseases, concurrent medications, and general physical condition.

Position of the American Dietetic Association: the impact of fluoride on health

Fluoride is an important element for mineralization of body tissues. The use of topical and systemic fluoride for oral health has resulted in major reductions in dental caries and its associated disability. Fluoridation of public water supplies has been endorsed by over 90 professional health organizations as the most effective dental public health measure in existence. Still, about half of the US population fails to receive the maximum benefits possible from community water fluoridation and the use of fluoride products. Fluoride also plays a role in bone health. The role of high doses of fluoride for prevention of osteoporosis is undergoing active study and is considered experimental at this point. Dietetics professionals should routinely monitor and promote the use of systemic and topical fluorides, especially in children and adolescents. The American Dietetic Association strongly reaffirms its endorsement of the use of systemic and topical fluorides, including water fluoridation, at appropriate levels of intake, as an important public health measure. However, clients should be cautioned that experimental use of high intakes of fluoride should be avoided unless they are participating in clinical trials.

A comparison of fluoride bioavailability from a sustained-release NaF preparation (Neosten) and other fluoride preparations

Twelve normal subjects completed a crossover study with sustained-release sodium fluoride (Neosten, 11.3 mg F), monofluorophosphate (MFP, 10 mg F), and plain sodium fluoride (P-NaF, 11.3 mg F). After each preparation was given with 400 mg calcium, serum fluoride (Fser) was measured for 24 hours, and pharmacokinetic data were calculated. Fluoride absorption in the Neosten group, as measured by change in the area under the curve (delta AUC) of Fser, was less than 33% of that in the MFP and P-NaF treated groups. Both peak Fser (Cmax) and peak-basal variation in the Neosten group were 25% that found in the other groups. t1/2 was nearly twofold greater after Neosten. MFP and P-NaF showed greater bioavailability than Neosten and much higher Cmax that exceeded the toxic threshold of Fser (190 ng/ml). These findings could explain the ineffectiveness of MFP and P-NaF observed in recent clinical trials.

Metastable Equilibrium Solubility Behavior of Carbonated Apatites in the Presence of Solution Fluoride

The aims of the present investigation were to assess the applicability of the metastable equilibrium solubility (MES) concept for the carbonated apatites (CAPs) over a range of pH and a wide range of solution fluoride concentrations and to examine the hypothesis that, in the presence of solution fluoride, a surface complex with the stoichiometry of fluorapatite (FAP) governs the MES behavior. Two CAP samples were prepared by precipitation from reaction media containing calcium nitrate (Ca(NO(3))(2).4H(2)O) and sodium phosphate (NaH(2)PO(4).H(2)O) at two different levels of sodium bicarbonate. The MES distributions of the two CAP preparations were determined by equilibrating approximately 10 mg of CAP powder in 2 L of 0.1 M acetate buffers (ionic strength=0.50 M) at pH 4.5 and 5.5 and at various levels of calcium, phosphate, and fluoride. The fluoride concentrations ranged from 0.03 to 12 ppm. From the compositions of the equilibrating buffer solutions, ion activity products based upon the stoichiometries of hydroxyapatite (HAP) and FAP were calculated in an attempt to determine the correct function governing the dissolution of the CAP preparations. The results of this study demonstrated that both CAP preparations exhibit the MES distribution phenomenon in solution media of varying pH and fluoride concentrations. Furthermore, the experimental MES data obtained with both CAP preparations at the lower pH (4.5) and at higher solution fluoride levels (>/=0.1 ppm) were essentially superimposable when plotted against the ion activity product based upon the stoichiometry of FAP, suggesting that in the presence of solution fluoride the MES governing surface complex may be an entity possessing a stoichiometry approximated by that of FAP. When the HAP stoichiometry was assumed to represent the surface complex, good superposition of the data was not possible. Copyright 2000 Academic Press.

Prevention and treatment of osteoporosis: efficacy of combination of hormone replacement therapy with other antiresorptive agents

Osteoporosis is a debilitating disease characterized by decreased bone mineral density (BMD) leading to fractures. It primarily affects postmenopausal women and elderly men. Prevention of osteoporosis is very important because present therapies do not have the potential to mend damage to the bone microarchitecture caused by osteoporosis. The first line of prevention and treatment of osteoporosis is hormone replacement therapy (HRT). All of the approved drugs for the prevention and treatment of osteoporosis act as inhibitors of bone resorption; these drugs include HRT, selective estrogen receptor modulators, calcitonin, and bisphosphonates. The latter two drugs have also been shown to prevent fractures. This article discusses data from nine controlled prospective clinical studies. Study 1 was designed to assess the efficacy of combined HRT and bisphosphonate in preventing osteoporosis during the early stages of menopause. This combined therapy increased the lumbar spine BMD by 10.9% and femoral BMD by 7.3% over 4 yr, compared with 6.8 and 4.0% with HRT alone, and 6.8 and 1.2% with bisphosphonate alone. Study 2 was conducted on postmenopausal women with established osteoporosis. These results showed a 10.4 and 7.0% increase in BMD in vertebrae and femora, respectively, compared with 7.3 and 4.8% increases in the HRT group, and 6.8 and 0.9% in the bisphosphonate group. Data from study 3 demonstrated similar findings in that the combination of alendronate and HRT also enhanced BMD values. Studies 4 and 5 assessed the efficacy of the combined therapy of HRT and calcitonin in the prevention of early postmenopausal bone loss. Both studies demonstrated a significant increase in BMD over and above that observed with either HRT or calcitonin alone. Studies 6, 7, and 8 demonstrated that the addition of testosterone to estrogen therapy further increased BMD when compared to estrogen therapy alone, and also prevented the expected decreases in markers of bone formation in early postmenopausal women. Study 9 demonstrated a synergistic effect on BMD in postmenopausal women, when HRT was coadministered with monofluorophosphate. Other combination therapies may also enhance BMD (e.g., the combination of alendronate and parathyroid hormone [PTH]). However, some agents either lose their efficacy or have no added effects on BMD when they are coadministered (e.g., tiludronate and PTH, calcitonin and PTH, calcitonin and anabolic steroids). These studies illustrate that in a subgroup of patients (i.e., patients with high bone turnover and/or severe osteoporosis), specific combination treatments such as HRT with bis-phosphonates, calcitonin, or androgens (and perhaps also with PTH, fluoride, nitric oxide donors) provide additional beneficial effects over a single-drug therapy. Whether these combination therapies are more effective than individual drugs in reducing fractures still needs to be determined.

Prevention and treatment of osteoporosis in the elderly

Due to age-associated bone losses, all elderly are prone to osteoporosis, which often leads to fractures. Fractures frequently result in dependency and institutionalization, as well as physical deformities that may lead to respiratory and cardiovascular problems. Currently, no drugs exist to promote new bone formation. Thus care of the elderly focuses primarily on lifestyle modification and increased dietary intake of calcium and vitamin D; decreased intake of caffeine, phosphates, and alcohol; smoking cessation; increased exercise; and drugs. Drugs for preventing osteoporosis include supplemental calcium and vitamin D, hormone replacement therapy, and alendronate. Drugs that enhance bone loss or increase the likelihood of falls should be eliminated, if possible, or the dosages adjusted. Making residences safer will also help to minimize the potential for falls. Drugs for treating osteoporosis include hormone replacement therapy, alendronate, and nasal calcitonin. The prevention and treatment plan is individualized for each patient, taking into account personal preferences, risk factors for osteoporosis and fracture, concomitant diseases and drug therapies, efficacy and tolerance of osteoporosis therapy, quality of life, life expectancy, finances, and health insurance coverage.

Osteoporosis: intervention options

Osteoporosis is a systemic progressive disease with important clinical complications because of the fractures that arise and cause major morbidity in especially the aging postmenopausal women. Because of the relative not complex procedure of diagnosis and prediction the most important question to answer: is treatment possible? There are now a variety of treatments available for the management of osteoporosis. The inhibitors of bone resorption, which include calcium, the vitamin Ds, bisphosphonates, calcitonins and gonadal steroids have been variously shown to prevent bone loss or to reduce fractures. On the other hand bone formation stimulating agents as fluorides and in the near future parathyroid hormone and analogues must be considered also. However, randomized clinical trials with fractures as clinical endpoints are only few in number and not present for every suggested treatment. During the last 3 years it has become clear that besides estrogen, bisphosphonates and now perhaps the selective estrogen receptor modulators also show a good alternative as intervention option of postmenopausal osteoporosis. At this moment sodium fluoride is not the first choice in treatment of osteoporosis in general practice.

Minocycline for the treatment of rheumatoid arthritis

The scientific basis for the use of antibiotics (with special emphasis on tetracycline and its derivatives) in the treatment of RA is discussed. The data on efficacy and toxicity are presented. The possible place of tetracycline derivatives within the overall strategy of RA treatment is also presented.