Contribution of a heating element to topical anesthesia patch efficacy prior to vascular access: results from two randomized, double-blind studies.

CONTEXT: Pain associated with superficial procedures, including intravenous (IV) access procedures, should be prevented when possible, especially in children. OBJECTIVES: To evaluate a topical local anesthetic patch containing lidocaine 70 mg/tetracaine 70 mg with a heating element designed to warm the skin and facilitate rapid delivery of local anesthetics into the skin. The pilot study was designed to provide data to inform the design of the definitive study to evaluate the impact of controlled heat on the efficacy of the lidocaine/tetracaine patch (patch) when applied before IV cannulation. METHODS: Subjects in the pilot study were randomized to eight groups that varied by heated vs. unheated patch, 20 vs. 30 minute application, and 16 vs. 18 G catheter. Subjects in the definitive study were randomized in a double-blind manner to receive either the heated or unheated patch, 20 minutes before vascular access, using a 16 G catheter in the antecubital space of the arm. In both studies, the primary efficacy measure was subject-reported pain intensity using a visual analog scale. RESULTS: Pilot study: Subjects who received the heated patch (n=43) vs. the unheated patch (n=37) had lower mean pain intensity scores (14.7 vs. 23.5mm, P=0.04). Pain intensity scores did not differ significantly by application time, but the difference between the 16 and 18 G catheter groups approached statistical significance (22.8 vs. 14.9 mm, P=0.05). Definitive study: Mean pain intensity scores for the heated patch group (n=124) vs. the unheated patch group (n=126) were 14.2 and 20.5mm, respectively (P=0.006). CONCLUSION: Heated patches provided significantly better pain relief compared with unheated patches. All the subjects tolerated the patches well, with few adverse effects.

Use of accelerator mass spectrometry to measure the pharmacokinetics and peripheral blood mononuclear cell concentrations of zidovudine.

The remarkable sensitivity of accelerator mass spectrometry (AMS) is finding many new applications in pharmacology. In this study AMS was used to measure [(14)C]-Zidovudine (ZDV) concentrations at the drug's site of action (peripheral blood mononuclear cells, PBMCs) following a dose of 520 ng (less than one-millionth of the standard daily dose) to a healthy volunteer. In addition, the pharmacokinetics of this microdose were determined and compared to previously published parameters for therapeutic doses. Microdose ZDV pharmacokinetic parameters fell within reported 95% confidence intervals or standard deviations of most previously published values for therapeutic doses. Blood, urine, stool, saliva, and isolated PBMCs were collected periodically through 96 h postdose and analyzed for ZDV and metabolite concentrations. The results showed that ZDV is rapidly absorbed and eliminated, has one major metabolite, and is sequestered in PBMCs. (14)C mass balance assessments indicated a significant portion of ZDV remained after 96 h with a much prolonged elimination half-life. Results of this study demonstrate the usefulness of microdosing and AMS as a tool for studying the pharmacokinetic characteristics, including PBMC concentrations, of ZDV and underscore the value of AMS as a tool with which to perform pharmacokinetic and mass balance studies using trace amounts of radiolabeled compound.

How useful are measures of BMD and bone turnover?

Measurements of bone mineral density (BMD) and biochemical markers of bone turnover are useful in the diagnosis and management of osteoporosis, as well as in research relating to the pathogenesis and treatment of the disease. Recent challenges to the utility of these measures have resulted in some confusion among both researchers and clinicians. BMD accounts for the great majority of bone strength and is the current gold standard for the diagnosis of osteoporosis, as well as for prediction of fracture risk. Although bone turnover increases sharply after menopause, biochemical markers of bone turnover have limited usefulness in fracture risk prediction. Persistently elevated bone turnover throughout the menopause is associated with structural decrements, cannot be measured routinely and non-invasively. In research applications, both BMD and markers of bone turnover are used to identify candidate agents in preclinical and clinical studies. In addition, head-to-head comparisons of treatments utilize these measures, because fracture endpoint trials would need to be extraordinarily large and complex. Analyses that have suggested that change in BMD or bone turnover 'explains' little of change in fracture risk with treatment appear to be flawed. Although neither can perfectly predict fracture, they are our current best alternatives.

Ibandronate produces significant, similar antifracture efficacy in North American and European women: new clinical findings from BONE.

OBJECTIVES: BONE (oral iBandronate Osteoporosis vertebral fracture trial in North America and Europe) determined whether less frequent dosing of ibandronate (dose-free interval > 2 months) provided similar antifracture efficacy to daily dosing. As osteoporosis medications must be effective across different populations, an additional objective of BONE was to investigate and report the effect of oral ibandronate in North American and European women, as described here. PATIENTS AND METHODS: BONE was a randomized, double-blind, placebo-controlled, fractureprevention study in 2946 postmenopausal women (age 55 years-80 years; > or = 5 years since menopause) with osteoporosis (low lumbar spine bone mineral density and one to four prevalent vertebral fractures [T4-L4]). Participants received daily calcium (500 mg) and vitamin D (400 IU) plus either placebo, oral daily ibandronate (2.5 mg) or oral intermittent ibandronate (20 mg every other day for 12 doses every 3 months). The efficacy and tolerability of ibandronate were assessed independently in both North American and European populations. RESULTS: Consistent, significant efficacy was observed in the North American (new vertebral fracture risk reduction: 60% and 54% with daily and intermittent ibandronate, respectively) and European patient populations (50% and 48%, respectively). Both ibandronate regimens also significantly reduced the incidence of new, worsening, and acute clinical, vertebral fractures. Daily and intermittent ibandronate significantly increased bone density at the spine in both North American (5.4% and 4.4% vs. baseline with daily and intermittent ibandronate, respectively) and European (7.1% and 6.3% vs. baseline, respectively) populations. Significant increases were also observed for total hip bone density (2.6% and 3.7% vs. baseline for daily, and 2.5% and 3.1% for intermittent; North American and European populations, respectively). Comparable, significant decreases in biochemical markers of bone turnover (reductions in urinary excretion of C-telopeptide levels of 53.5% and 67.1% vs. baseline for daily, and 50.0% and 53.8% for intermittent; North American and European populations, respectively) were also observed in both populations (p < 0.004 for all cited measurements in each ibandronate group vs. placebo). Oral ibandronate was well tolerated in both North American and European patients, with a safety profile similar to placebo. CONCLUSIONS: Oral ibandronate, administered daily or intermittently, effectively reduced vertebral fracture risk in North American and European women with postmenopausal osteoporosis. These results demonstrate the efficacy of ibandronate administered with extended dose-free intervals, regardless of patients' geographical origin. Research investigating other less frequent ibandronate regimens, such as once-monthly oral administration, is underway.

Changes in bone density and turnover after alendronate or estrogen withdrawal.

OBJECTIVE: To compare bone mineral density (BMD) and bone turnover changes after therapy withdrawal in postmenopausal women treated with alendronate or estrogen-progestin. DESIGN: In this randomized, blinded, multinational, placebo-controlled trial, 1,609 healthy postmenopausal women ages 45 to 59 years were assigned to receive alendronate, placebo, or open-label estrogen-progestin (conjugated equine estrogens plus medroxyprogesterone acetate or a cyclic regimen of 17 beta-estradiol, norethisterone acetate and estradiol). Of the original women, one third after year 2 and one third after year 4 were switched from alendronate to placebo, while remaining blinded to treatment assignment. The women taking estrogen-progestin in years 1 to 4 were followed off therapy in years 5 and 6. BMD at the lumbar spine and hip and biochemical markers of bone turnover were measured. RESULTS: The treatment groups described in the current report represent 860 women at baseline; 481 women entered year 5, and 430 completed 6 years. BMD steadily decreased in the placebo group during all 6 years. In contrast, spine and hip BMD increased during the first 4 years in the groups receiving daily continuous alendronate 5 mg and estrogen-progestin. During years 5 and 6, BMD decreased at the lumbar spine -2.42% (95% CI = -4.10, -0.74) and total hip -1.09% (-2.60, 0.41) in the group previously treated with alendronate 5 mg for 4 years. In comparison, large BMD decreases were observed at the spine [-7.69% (-8.96, -6.41)] and total hip [-5.16% (-6.30, -4.01)] among women who had received estrogen-progestin for 4 years. CONCLUSION: Alendronate produces greater residual skeletal effects than estrogen-progestin after therapy discontinuation.

Prevention of postmenopausal bone loss: six-year results from the Early Postmenopausal Intervention Cohort Study.

We report the effect of continuous treatment with alendronate for 6 yr vs. placebo in the Early Postmenopausal Intervention Cohort study. A total of 1609 healthy, early postmenopausal women were recruited; we describe results for the 585 women who received continuous placebo or alendronate (2.5 or 5 mg) daily for 6 yr. Bone mineral density (BMD) was evaluated at the lumbar spine, hip, forearm, and total body at baseline and annually thereafter. Bone turnover markers were measured every 6 months from baseline to yr 2 and annually thereafter. Adverse experiences, including upper gastrointestinal events and fractures, were recorded throughout the study. Women receiving placebo experienced progressive decreases in BMD at all skeletal sites. Patients receiving alendronate experienced significant gains in spine and hip BMD that were maintained through yr 6. Significantly greater, dose-related decreases in bone turnover markers in the alendronate groups vs. placebo occurred within the first year and were sustained through yr 6. Women receiving alendronate had adverse experience incidences similar to those receiving placebo. Fractures occurred in 11.5, 10.3, and 8.9% of women taking placebo, 2.5 mg alendronate, or 5 mg alendronate daily, respectively. Therapy with alendronate is an effective and promising strategy for the prevention of postmenopausal osteoporosis.

Oral daily ibandronate prevents bone loss in early postmenopausal women without osteoporosis.

UNLABELLED: Oral daily ibandronate was investigated for the prevention of bone loss in postmenopausal women without osteoporosis (n = 653). BMD at the lumbar spine and hip were significantly increased (3.1% and 1.8%, respectively; p < or = 0.0001 versus placebo) with 2.5 mg ibandronate after 24 months. Oral ibandronate is a promising option for the prevention of postmenopausal bone loss. INTRODUCTION: Further strategies to manage patients most at risk from developing postmenopausal osteoporosis are required. The objectives of this multicenter, double-blind, randomized, placebo-controlled study were to examine the efficacy, tolerability, and optimal dose of oral daily ibandronate in the prevention of bone loss in postmenopausal women. MATERIALS AND METHODS: In total, 653 women (mean bone mineral density [BMD] T-score > -2.5 at the lumbar spine), who had been postmenopausal for at least 1 year, were allocated to one of four strata based on time since menopause and baseline lumbar spine BMD. Women were randomized to receive calcium (500 mg daily) plus either placebo (n = 162) or ibandronate 0.5 mg (n = 162), 1 mg (n = 166), or 2.5 mg (n = 163) as once-daily oral treatment for 2 years. The primary endpoint was the mean percent change in lumbar spine BMD with ibandronate versus placebo. RESULTS AND CONCLUSIONS: After 2 years, oral daily ibandronate produced a dose-related and sustained maintenance or increase in BMD at the lumbar spine and hip (total hip, femoral neck, trochanter), together with a dose-related reduction in the rate of bone turnover. The greatest nominal increases in spinal and hip BMD were observed with the 2.5-mg dose, which produced statistically significant BMD gains compared with placebo at 6 months and all subsequent time-points at the spine and hip (3.1% and 1.8% increase in lumbar spine and total hip BMD, respectively, versus placebo; p < or = 0.0001 after 24 months). Oral daily ibandronate was well tolerated with an incidence of upper gastrointestinal adverse events similar to placebo. No safety concerns were identified. In summary, oral daily ibandronate 2.5 mg decreases bone turnover, preserves or increases BMD in the spine and proximal femur, and is well tolerated. Oral ibandronate provides a promising option for the prevention of bone loss in postmenopausal women.

What are the criteria by which a densitometric diagnosis of osteoporosis can be made in males and non-Caucasians?

Osteoporotic fractures are not rare in men or non-Caucasian women. However, for these groups, there is no consensus densitometric definition of osteoporosis. As is the case in Caucasian women, low bone mineral density (BMD) is associated with increased fracture risk among men and non-Caucasian women; thus, a densitometric definition of osteoporosis seems feasible. Reaching agreement on criteria for diagnosing osteoporosis in men and non-Caucasians was among the goals of the International Society for Clinical Densitometry Position Development Conference held in July 2001. To this end, the conference recommendation for males is that osteoporosis be defined as a BMD T-score of -2.5 or below the young normal mean for men. Since the relationship between BMD and fracture risk may differ between men and women, it is recommended that T scores in men continue to be derived using a male normative database. Similarly, for non-Caucasians, the recommendation is to diagnose osteoporosis at or below a T-score of -2.5. However, given the difficulty in defining race or ethnic groups, a dearth of data, and their conflicting nature correlating BMD with fracture risk in different ethnicities, it is recommended that a uniform normative database (not adjusted for race) be utilized in the United States for T-score derivation in non-Caucasians. Note that these are current clinical recommendations, which may change as additional data accumulate. Furthermore, there was agreement that the following individuals should have their bone density measured: anyone (male or female, regardless of race) with prior fragility fractures or with conditions widely recognized to increase the risk of bone loss and fracture (such as hypogonadism, corticosteroid treatment, hyperparathyroidism, alcohol abuse, anticonvulsant use, and prior gastrectomy); women on long-term hormone replacement therapy; and in the absence of these conditions, women age 65 and older (regardless of race) and men age 70 and older.

Changes in bone density and turnover explain the reductions in incidence of nonvertebral fractures that occur during treatment with antiresorptive agents.

Some, but not all, antiresorptive agents have been shown to reduce the risk of nonvertebral fractures. Agents that significantly reduced nonvertebral fracture risk also appear to produce larger mean increases in bone mineral density (BMD) and reductions in biochemical markers (BCM) of bone turnover, compared with other agents. To examine the extent to which increases in BMD and reductions in BCM during antiresorptive therapy are associated with reductions in risk of nonvertebral fractures, we performed a meta-analysis of all randomized, placebo-controlled trials of antiresorptive agents conducted in postmenopausal women with osteoporosis (i.e. prior vertebral fracture or low BMD) with available relevant data. A total of 18 such trials with usable data were identified, including a total of 2,415 women with incident nonvertebral fractures over 69,369 women-years of follow-up. Poisson regression was used to estimate the association between changes in BMD or BCM during the first year and overall reductions in risk of nonvertebral fractures (vs. the placebo group) across all trials. Larger increases in BMD and larger reductions in BCM were significantly associated with greater reductions in nonvertebral fracture risk. For example, each 1% increase in spine BMD at 1 yr was associated with an 8% reduction in nonvertebral fracture risk (P = 0.02). Mean BMD changes at the hip were smaller than at the spine, but the predicted net effect on fracture risk was the same; an agent that increases spine BMD by 6% at 1 yr reduces nonvertebral fracture risk by about 39%, and an agent that increases hip BMD by 3% at 1 yr reduces nonvertebral fracture risk by about 46%. The results also predict that a 70% reduction in resorption BCM would reduce risk by 40%, and a 50% reduction in formation BCM would reduce risk by 44%. It appears that either BMD or BCM changes are able to explain the effect of treatment, because a separate variable for treatment was not independently significant in any models. These data demonstrate that larger increases in BMD at both the spine and hip and larger reductions in both formation and resorption BCM are associated with greater reductions in the risk of nonvertebral fractures. Antiresorptive agents that do not produce large increases in BMD or large reductions in BCM do not appear to and would not be expected to decrease the risk of nonvertebral fractures.

Relationship between phalangeal bone density and risk of vertebral fracture.

The aims of our study were to determine the relationship between bone mineral density (BMD) measurements of the phalanges obtained with the accuDEXA and recent vertebral fractures. To determine whether osteoarthritis of the hands affects phalangeal BMD measurements, and to illustrate the conversion of phalangeal BMD measurements to absolute fracture risk estimates for clinical application. The prospective Hawaii Osteoporosis Study began in 1981, and incident vertebral fractures were identified from serial radiographs obtained at approx 2-yr intervals. Vertebral fractures occurring between 1993 and 1994 and 1997 and 1998 were compared to phalangeal BMD measurements obtained in 1997-1998. A total of 199 women participated in this case-control study. The association of the phalangeal BMD measurements with vertebral fractures was examined in age-adjusted, logistic regression models. Results are expressed as odds ratios (ORs) per SD difference in the phalangeal BMD measurements. Osteoarthritis of the hands was graded according to the Kellgren-Lawrence scale. There were 34 incident fractures since the eighth examination in 1993-1994. For vertebral fractures, the OR per SD of phalangeal BMD was 1.5 (1.0-2.1). Phalangeal BMD was not influenced significantly by established osteoarthritis (p = 0.68). Phalangeal BMD measurements obtained with the accuDEXA device relate to recent vertebral fractures and can be used to identify women at high risk of fractures. The phalangeal BMD measurements obtained with this device are not significantly influenced by the presence of osteoarthritis of the hands.