Current management strategies for hypercalcemia

Drug Repurposing of Selected Antibiotics: An Emerging Approach in Cancer Drug Discovery

Drug repurposing is a method of investigating new therapeutic applications for previously approved medications. This repurposing approach to "old" medications is now highly efficient, simple to arrange, and cost-effective and poses little risk of failure in treating a variety of disorders, including cancer. Drug repurposing for cancer therapy is currently a key topic of study. It is a way of exploring recent therapeutic applications for already-existing drugs. Theoretically, the repurposing strategy has various advantages over the recognized challenges of creating new molecular entities, including being faster, safer, easier, and less expensive. In the real world, several medications have been repurposed, including aspirin, metformin, and chloroquine. However, doctors and scientists address numerous challenges when repurposing drugs, such as the fact that most drugs are not cost-effective and are resistant to bacteria. So the goal of this review is to gather information regarding repurposing pharmaceuticals to make them more cost-effective and harder for bacteria to resist. Cancer patients are more susceptible to bacterial infections. Due to their weak immune systems, antibiotics help protect them from a variety of infectious diseases. Although antibiotics are not immune boosters, they do benefit the defense system by killing bacteria and slowing the growth of cancer cells. Their use also increases the therapeutic efficacy and helps avoid recurrence. Of late, antibiotics have been repurposed as potent anticancer agents because of the evolutionary relationship between the prokaryotic genome and mitochondrial DNA of eukaryotes. Anticancer antibiotics that prevent cancer cells from growing by interfering with their DNA and blocking growth of promoters, which include anthracyclines, daunorubicin, epirubicin, mitoxantrone, doxorubicin, and idarubicin, are another type of FDA-approved antibiotics used to treat cancer. According to the endosymbiotic hypothesis, prokaryotes and eukaryotes are thought to have an evolutionary relationship. Hence, in this study, we are trying to explore antibiotics that are necessary for treating diseases, including cancer, helping people reduce deaths associated with various infections, and substantially extending people's life expectancy and quality of life.

Association between vitamin D and zoledronate-induced acute-phase response fever risk in osteoporotic patients

OBJECTIVES

To elucidate the independent correlation between vitamin D content and zoledronate (ZOL)-triggered acute-phase response (APR) fever risk in osteoporotic (OP) patients, and to examine the potential threshold for optimal vitamin D concentrations that prevent the occurrence of ZOL-induced fever.

METHODS

This retrospective investigation was based on a prospectively documented database compiled at the Affiliated Kunshan Hospital of Jiangsu University between January 2015 and March 2022. In total, 2095 OP patients, who received ZOL during hospitalization, were selected for analysis. The primary endpoint was the presence (>37.3°C) or absence (≤37.3°C) of fever, quantified by the maximum body temperature, measured within 3 days of ZOL infusion. The exposure variable was the baseline serum 25-hydroxyvitamin D (25[OH]D) levels.

RESULTS

The OP patients with fever exhibited markedly reduced 25(OH)D content than those without fever. Upon adjusting for age, gender, order of infusion of ZOL, main diagnosis, season of blood collection, year of blood collection, calcitonin usage, and beta-C-terminal telopeptide of type I collagen (β-CTX) levels, a 10 ng/mL rise in serum 25(OH)D content was correlated with a 14% (OR, 0.86; 95% CI, 0.76 to 0.98, P-value = 0.0188) decrease in the odds of ZOL-induced fever. In addition, a non-linear relationship was also observed between 25(OH)D levels and fever risk, and the turning point of the adjusted smoothed curve was 35 ng/mL of serum 25(OH)D content.

CONCLUSIONS

Herein, we demonstrated the independent negative relationship between serum 25(OH)D content and ZOL-induced fever risk. According to our analysis, 25(OH)D above 35 ng/mL may be more effective in preventing ZOL-induced APR. If this is confirmed, a "vitamin D supplemental period" is warranted prior to ZOL infusion, particularly the first ZOL infusion, to ensure appropriate 25(OH)D levels that protect against ZOL-induced fever.

The Effects of Voriconazole on Metabolism of All-Trans Retinoic Acid in the Treatment of Acute Promyelocytic Leukemia: A Case Report

All-trans retinoic acid (ATRA) is a derivative of vitamin A and is the mainstay treatment of acute promyelocytic leukemia (APL). Hypercalcemia is a rare yet important side-effect of ATRA, especially when it is used concomitantly with a medication that impedes its metabolism by inhibiting cytochrome P-450 in the liver and thus increasing the duration of exposure to ATRA. Azole antifungal drugs such as voriconazole are frequently used in patients undergoing chemotherapy due to a high incidence of fungal infections. These medications inhibit two vital enzymes of cytochrome P-450, CYP2C9 and CYP3A4, potentiating the effects of ATRA on calcium metabolism. We present a case of a nine-year-old girl who underwent chemotherapy with all-trans retinoic acid for acute promyelocytic leukemia. The patient was given an anti-fungal cover with voriconazole for extensive fungal chest infection simultaneously. She was found to have asymptomatic hypercalcemia on routine follow-up during the consolidation phase. Both medications were stopped. Subsequently, she was admitted to the ward and managed conservatively with hydration. Serum calcium levels were returned to normal within six days after stopping the combination of ATRA and voriconazole. We underscore that the use of anti-fungal medications should be limited while using ATRA. However, strict monitoring must be done when a combination of these drugs is started, if necessary.

Bisphosphonate Versus Bisphosphonate and Calcitonin for the Treatment of Moderate to Severe Hypercalcemia of Malignancy

BACKGROUND

Historically, intravenous (IV) bisphosphonates with calcitonin are the treatment of choice for hypercalcemia of malignancy. However, evidence is lacking.

OBJECTIVE

The objective of this study was to compare the use of bisphosphonate versus bisphosphonate with calcitonin for moderate to severe hypercalcemia of malignancy.

METHODS

This was a retrospective study evaluating patients who received bisphosphonate and/or calcitonin for treatment of moderate to severe hypercalcemia of malignancy. Patients received usual care plus either (1) bisphosphonate or (2) bisphosphonate with calcitonin. The primary outcome was change in corrected serum calcium concentrations 48 hours after treatment. Secondary outcomes included corrected calcium levels, incidence of normocalcemia and hypocalcemia, time to normocalcemia, hospital length of stay, and cost avoidance.

RESULTS

The 48-hour decrease in corrected calcium was less in the bisphosphonate group than in the combination group (2.4 [1.6-3.4] vs 3.9 [3.5-5.3]; P < 0.001). However, initial calcium levels in the combination group were higher than in the bisphosphonate group, and calcium levels at 24, 48, and 72 hours were similar. Secondary outcomes did not differ. Average cost avoidance with bisphosphonate monotherapy was $11 248 per patient and $291 448 per year.

CONCLUSIONS AND RELEVANCE

In the treatment of moderate to severe hypercalcemia of malignancy, IV bisphosphonate in combination with calcitonin resulted in a higher difference in corrected calcium levels at 48 hours compared with bisphosphonate therapy alone. However, corrected calcium levels in the first 72 hours, time to normocalcemia, and clinical outcomes were similar. The addition of calcitonin increases cost without substantial clinical benefit, and providers may consider avoiding calcitonin.

Surgical neurolysis for the treatment of neuropathic pain in 2 postmenopausal women with mandibular necrosis resulting from oral bisphosphonates

We analyze the use of surgical neurolysis for the treatment of neuropathic pain of the inferior alveolar nerve. For that, 3 surgical neurolysis were performed on 2 postmenopausal women experiencing neuropathic pain of the inferior alveolar nerve due to mandibular necrosis resulting from treatment with oral bisphosphonates. Both patients showed sensory impairment of the inferior alveolar nerve. We obtained complete control of neuropathic pain after 6 months of the patients' evolution, preserving the function of the lingual nerve in all 3 neurolysis, without causing any impact as regards to the sensitive situation before treatment. Surgical neurolysis of the inferior alveolar nerve may be considered as the choice therapeutic technique to treat neuropathic pain of this nerve when there is a sensory impairment in patients showing mandibular necrosis resulting from bisphosphonates.

Calcium, magnesium, and phosphate abnormalities in the emergency department

Derangements of calcium, magnesium, and phosphate are associated with increased morbidity and mortality. These minerals have vital roles in the cellular physiology of the neuromuscular and cardiovascular systems. This article describes the pathophysiology of these mineral disorders. It aims to provide the emergency practitioner with an overview of the diagnosis and management of these disorders.

Neurologic complications of electrolyte disturbances and acid-base balance

Electrolyte and acid-base disturbances are common occurrences in daily clinical practice. Although these abnormalities can be readily ascertained from routine laboratory findings, only specific clinical correlates may attest as to their significance. Among a wide phenotypic spectrum, acute electrolyte and acid-base disturbances may affect the peripheral nervous system as arreflexic weakness (hypermagnesemia, hyperkalemia, and hypophosphatemia), the central nervous system as epileptic encephalopathies (hypomagnesemia, dysnatremias, and hypocalcemia), or both as a mixture of encephalopathy and weakness or paresthesias (hypocalcemia, alkalosis). Disabling complications may develop not only when these derangements are overlooked and left untreated (e.g., visual loss from intracranial hypertension in respiratory or metabolic acidosis; quadriplegia with respiratory insufficiency in hypermagnesemia) but also when they are inappropriately managed (e.g., central pontine myelinolisis when rapidly correcting hyponatremia; cardiac arrhythmias when aggressively correcting hypo- or hyperkalemia). Therefore prompt identification of the specific neurometabolic syndromes is critical to correct the causative electrolyte or acid-base disturbances and prevent permanent central or peripheral nervous system injury. This chapter reviews the pathophysiology, clinical investigations, clinical phenotypes, and current management strategies in disorders resulting from alterations in the plasma concentration of sodium, potassium, calcium, magnesium, and phosphorus as well as from acidemia and alkalemia.

Hypercalcemia induced by Rosai-Dorfman disease in a hemodialysis patient: histological evidence of extrarenal calcitriol overproduction

Rosai-Dorfman disease (RDD) is a rare disorder characterized by the proliferation of histiocytes in the sinus of the affected lymph nodes, which leads to massive lymphadenopathy. RDD usually presents as an increased inflammatory response and lymph node swelling. We herein report the case of a hemodialysis patient with a fever, hypercalcemia and increased serum calcitriol level who was histologically diagnosed to have RDD. Immunohistochemistry revealed an increased expression of 1α-hydroxylase by histiocytes in the dilated sinus, indicating the extrarenal overproduction of calcitriol. Treatment with oral prednisolone decreased the serum levels of inflammatory markers and calcitriol, normalized the serum calcium level and mitigated the systemic lymph node enlargement.

RANKL, a necessary chance for clinical application to osteoporosis and cancer-related bone diseases

Osteoporosis is a common bone disease characterized by reduced bone and increased risk of fracture. In postmenopausal women, osteoporosis results from bone loss attributable to estrogen deficiency. Osteoclast differentiation and activation is mediated by receptor activator of nuclear factor-κB ligand (RANKL), its receptor receptor activator of nuclear factor-κB (RANK), and a decoy receptor for RANKL, osteoprotegerin (OPG). The OPG/RANKL/RANK system plays a pivotal role in osteoclast biology. Currently, a fully human anti-RANKL monoclonal antibody named denosumab is being clinically used for the treatment of osteoporosis and cancer-related bone disorders. This review describes recent advances in RANKL-related research, a story from bench to bedside. First, the discovery of the key factors, OPG/RANKL/RANK, revealed the molecular mechanism of osteoclastogenesis. Second, we established three animal models: (1) a novel and rapid bone loss model by administration of glutathione-S transferase-RANKL fusion protein to mice; (2) a novel mouse model of hypercalcemia with anorexia by overexpression of soluble RANKL using an adenovirus vector; and (3) a novel mouse model of osteopetrosis by administration of a denosumab-like anti-mouse RANKL neutralizing monoclonal antibody. Lastly, anti-human RANKL monoclonal antibody has been successfully applied to the treatment of osteoporosis and cancer-related bone disorders in many countries. This is a real example of applying basic science to clinical practice.

[Acute abdomen and hyperparathyroidism: a description of a case]

Hypercalcaemia secondary to primary hyperparathyroidism may present with an insidious clinical picture and involve multiple organs, which may lead to a delay in its diagnosis and erroneous therapeutic actions, due to its similarity to other different conditions. We describe the case of a patient who was admitted to our hospital with the diagnosis of acute abdomen. A laparotomy was performed which was negative. The slow post-operative progress and the clinical neurology of the patient was resolved after checking for the presence of a significant hypercalcaemia secondary to a parathyroid lymph node.

Parathyroid carcinoma: challenges in diagnosis and treatment

Parathyroid carcinoma is a malignant neoplasm affecting 0.5% to 5.0% of all patients with primary hyperparathyroidism. Since it was first described by De Quervain in 1904 to this day, it continues to defy diagnosis and treatment because of its rarity, overlapping features with benign parathyroid disease, and lack of distinct characteristics. En bloc surgical extirpation of the tumor with clear margins remains the best curative treatment. Although prolonged survival is possible with recurrent or metastatic disease, cure is rarely achievable. Efficacy of adjuvant therapies, such as radiotherapy and chemotherapy, in management of persistent, recurrent, or metastatic disease has been disappointing.

Recent advances in diagnosis and treatment of acute kidney injury in patients with cancer

Acute Kidney Injury (AKI) is a common complication in patients with cancer and even though there are many causes of renal failure in this population the classical classification of prerenal, renal, and postrenal is useful as a diagnostic guide. Important risk factors for AKI are dehydration, use of nephrotoxic drugs, preexisting renal impairment and large tumor burden. The development of AKI is associated with poor prognosis but early recognition and treatment initiation are associated with better outcomes in this population.

Establishment of a new murine model of hypercalcemia with anorexia by overexpression of soluble receptor activator of NF-κB ligand using an adenovirus vector

Hypercalcemia is a significant complication of certain human malignancies that is primarily caused by the release of calcium from bone due to marked bone resorption by osteoclast activation. Osteoclast differentiation and activation is mediated by receptor activator of NF-κB ligand (RANKL). Transgenic mice overexpressing murine soluble RANKL (sRANKL) that we generated previously exhibited severe osteoporosis accompanied with enhanced osteoclastogenesis, but never exhibited hypercalcemia. To analyze the relationship between serum concentration of sRANKL and hypercalcemia and generate a simple and quick hypercalcemia model, an adenovirus vector harboring murine sRANKL cDNA (Ad-sRANKL) was injected i.p. into male C57BL/6 mice. Sera were collected to measure the levels of sRANKL, calcium and biochemical markers of bone turnover. Food intake and body weight were measured every 3 or 4 days. All the mice were killed 2 weeks after the injection, and femurs were collected to measure bone structure and bone mineral density (BMD). Serum sRANKL and calcium increased, peaking on day 7. Food intake and body weight significantly declined on day 7. These results indicated that the mice had anorexia as a symptom of hypercalcemia. Increases in bone resorption and formation markers with a marked decrease in BMD were observed on day 14. These results reflect accelerated bone formation following activation of osteoclasts, indicating coupling between bone formation and resorption. In conclusion, a new murine model of hypercalcemia with anorexia was established by overexpressing sRANKL. This model would be useful for studies of hypercalcemia and coupling between bone formation and resorption.

Management of nonpsychiatric medical conditions presenting with psychiatric manifestations

There is a significant dilemma when underlying medical disorders present as psychiatric conditions. It is important to identify the medical condition because treatment and management strategies need to be directed to the presenting symptoms and also to the underlying medical condition for successful treatment of the patient. Some systemic disorders present with psychiatric manifestations more often than others. The pattern of psychiatric disturbance seen may be specific for a particular medical disorder but may also be varied. Many drug formulations and medications also may produce psychiatric presentations. This article considers the management of nonpsychiatric medical conditions presenting with psychiatric manifestations.

Haematological emergencies managing hypercalcaemia in adults and children with haematological disorders

Hypercalcaemia is a common metabolic complication of malignant disease often requiring emergency intervention. Although it is more frequently associated with solid tumours, malignancy-associated hypercalcaemia (MAH) is seen in a significant number of patients with blood diseases. Its association with myeloma and adult T-cell leukaemia/lymphoma is well recognized but the incidence of hypercalcaemia in other haematological neoplasms, affecting adults and children, is less clearly defined. Haematologists need to be familiar with the clinical manifestations of, the differential diagnosis to be considered and the most effective management strategies that are currently available for MAH. The key components of management of MAH include aggressive rehydration, specific therapy to inhibit bone resorption and, crucially, treatment of the underlying malignancy. Bisphosphonates have revolutionized the management of MAH over the last 20 years, however the elucidation of molecular pathways implicated in MAH is facilitating the development of more targeted approaches to treatment.

New method for calcium on the ADVIA analyzer is free from interference of gadolinium-type contrast agents

Recently, Siemens Diagnostics released a new calcium assay (CA_2) based on complex formation of calcium with Arsenazo III dye for use on the three automated, random access ADVIA Chemistry analyzers (1650, 2400, and 1200). We evaluated this method for analytical performance as well as potential interference from gadolinium-containing magnetic contrast agents. With Siemens Chemistry serum and urine controls, 2-levels each, the imprecision for the new method was (n=40 each): within-run and total CV of <2.2 and <3.8%, respectively, over all three platforms. The analytical range/linearity of the method (all three systems) was 1-16 mg/dl (serum or plasma) and 1-32 mg/dl (urine). The new method on all three platforms correlated well with a reference (Inductively Coupled Plasma Atomic Emission Spectroscopy) method (n=61, range 4.03-10.30 mg/dl). The ADVIA 1650 CA_2 method also correlated well with the Roche Modular system((R)) Calcium method. The new method showed <10% interference with unconjugated or conjugated bilirubin (50 mg/dl), hemoglobin (1,000 mg/dl), lipids (1,000 mg/dl), and two magnetic resonance contrast agents containing Gadolinium (OptiMARK((R)) 1 mmol/l and Omniscan 1.5 mmol/l). On the contrary, the Roche Calcium method showed significant negative interference with gadolinium-containing contrast agents. We conclude that the ADVIA Ca_2 method can measure serum, plasma, or urine calcium concentrations accurately and is also free from interferences of gadolinium-containing agents.

Milk-alkali syndrome in a middle-aged woman after ingesting large doses of calcium carbonate: a case report

INTRODUCTION

Most cases of hypercalcaemia are secondary to malignancy or primary hyperparathyroidism. Here we report a case of hypercalcaemia that we have attributed to milk-alkali syndrome.

CASE PRESENTATION

A 51-year-old Caucasian woman with a past history of thyroidectomy and parathyroidectomy secondary to thyroid cancer developed an altered mental state and had an extremely high calcium concentration of 22.8 mg/dl (5.7 mmol/l). Investigations included work up for malignancy and hyperparathyroidism. However, the hypercalcaemia was attributed to ingestion of large doses of calcium carbonate, leading to milk-alkali syndrome. She was managed with intravenous fluids and withdrawal of calcium carbonate. The patient responded well to treatment, with normalization of the calcium concentration and clinical improvement.

CONCLUSION

We present this case to remind clinicians of the importance of detailed history taking and of milk-alkali syndrome as a cause of hypercalcemia.

Mithramycin protects against dopaminergic neurotoxicity in the mouse brain after administration of methamphetamine

The present study was undertaken to examine the effects of mithramycin, an inhibitor of transcription factor Specificity protein (Sp)-1, on the behavioral changes and dopaminergic neurotoxicity in the mouse striatum after administration of methamphetamine (METH). Pretreatment with mithramycin (75, 150 or 300 microg/kg) did not alter acute hyperlocomotion in mice after a single administration of METH (3 mg/kg). However, the development of behavioral sensitization in mice after repeated administration of METH (3 mg/kg/day, once daily for 5 days) was significantly blocked by pretreatment with mithramycin (300 microg/kg). Furthermore, pretreatment with mithramycin (300 microg/kg) significantly attenuated the hyperthermia in mice after repeated administration of METH (3 mg/kgx3, 3-h intervals). Moreover, the combination of pretreatment and subsequent administration of mithramycin (75, 150 or 300 microg/kg) significantly attenuated the reductions of dopamine (DA), its major metabolite 3,4-dihydroxyphenylacetic acid (DOPAC) and DA transporter (DAT) in the striatum after repeated administration of METH (3 mg/kgx3, 3-h intervals), and these attenuations were dose dependent. These findings suggest that mithramycin attenuates the development of behavioral sensitization and dopaminergic neurotoxicity in mice after repeated administration of METH. Therefore, mithramycin could have potential for the treatment of METH abusers, particularly since this drug has been approved by the Food and Drug Administration in the United States. In the future, however, another Sp1 inhibitors with fewer side effects might be more appropriate.

Crystal structure of Baeyer-Villiger monooxygenase MtmOIV, the key enzyme of the mithramycin biosynthetic pathway

Baeyer-Villiger monooxygenases (BVMOs), mostly flavoproteins, were shown to be powerful biocatalysts for synthetic organic chemistry applications and were also suggested to play key roles for the biosyntheses of various natural products. Here we present the three-dimensional structure of MtmOIV, a 56 kDa homodimeric FAD- and NADPH-dependent monooxygenase, which catalyzes the key frame-modifying step of the mithramycin biosynthetic pathway and currently the only BVMO proven to react with its natural substrate via a Baeyer-Villiger reaction. MtmOIV's structure was determined by X-ray crystallography using molecular replacement to a resolution of 2.9 A. MtmOIV cleaves a C-C bond, essential for the conversion of the biologically inactive precursor, premithramycin B, into the active drug mithramycin. The MtmOIV structure combined with substrate docking calculations and site-directed mutagenesis experiments identifies several residues that participate in cofactor and substrate binding. Future experimentation aimed at broadening the substrate specificity of the enzyme could facilitate the generation of chemically diverse mithramycin analogues through combinatorial biosynthesis.

Comparison of perioperative management and outcome of parathyroidectomy between older and younger patients

BACKGROUND

The aim of this study was to compare the clinical status, surgical course, and outcomes of patients with primary hyperparathyroidism (PHPT), over the age of 70, with younger patients.

METHODS

Between 1996 and 2006, 951 patients underwent parathyroidectomies for PHPT, of whom 190 were over the age of 70. Patient data were collected from chart reviews and a computerized database.

RESULTS

Fewer older patients were asymptomatic at presentation. No between-group differences in serum calcium were seen; however, parathyroid hormone (PTH) levels were higher in the older group. Hospitalization time was longer for the elderly. Duration of surgery, surgical success rates, and postoperative complications were similar between the 2 groups.

CONCLUSION

Surgical treatment of PHPT has both physiological benefits and helps to preserve quality of life. Our findings suggest that there is no practical difference in perioperative management and surgical outcomes for older patients. Surgeons should consider parathyroidectomy in PHPT patients regardless of age.

Hypercalcemia

Laboratory reports of elevated serum calcium are common in both inpatient and outpatient settings. Distinguishing between measurements likely to cause symptoms and that require correction from those that are benign poses a challenge to the physician. Calcium stores, serum measurement, and regulation are reviewed as an introduction to understanding the etiology and treatment of hypercalcemia.

Anti-hypercalcemic effect of orally administered recombinant Saccharomyces cerevisiae expressing salmon calcitonin on hypercalcemic rats

Oral delivery of salmon calcitonin (sCT) to rats via a recombinant Saccharomyces cerevisiae was assessed. A synthetic sCT gene was cloned and expressed in S. cerevisiae yAGA2-sCT. Recombinant salmon calcitonin (rsCT) expression was detected by flow cytometry. The resorption activity of osteoclasts was inhibited by 3 x 10(-6 )M rsCT. Oral administration of 5 g lyophilized yAGA2-sCT/kg to hypercalcemic rats decreased serum calcium from 2.8 +/- 0.02-2.7 +/- 0.02 mM.

Parathyroid carcinoma

PURPOSE OF REVIEW

This article reviews current knowledge on the etiology, diagnosis and treatment of parathyroid carcinoma.

RECENT FINDINGS

Due to its rarity, research on the molecular etiology and treatment of parathyroid carcinoma has been slow. Mutations of the tumor suppressor gene, HRPT2, and resultant loss of expression of its gene product have been found in the majority of parathyroid cancers studied. Recent advances in the field have identified regions on several chromosomes that demonstrate loss of heterozygosity more commonly in parathyroid carcinoma than in benign parathyroid lesions. This has provided clues to the location and identity of additional tumor suppressor genes associated with the development of this cancer.

SUMMARY

Parathyroid carcinoma is an extremely rare cause of primary hyperparathyroidism, accounting for fewer than 1% of cases. The etiology of parathyroid cancer is largely unknown. Associations have been made with several inherited syndromes and with specific genetic lesions. Little is known about the most appropriate management of this disease. En bloc resection at the time of initial surgery appears to provide the best chance of cure. Anecdotal experience with adjuvant chemotherapy has shown a modest and short-lived effect. External beam radiation following surgical resection, however, may increase long-term survival compared with surgery alone. Bisphosphonates and a new class of drugs known as calcimimetics have been used effectively in some patients to control the symptoms of severe hypercalcemia in a palliative setting.

Current Pharmacological Options for the Management of Primary Hyperparathyroidism

Drugs for treating primary hyperparathyroidism can be divided into two main groups: (i) antiresorptive drugs that inhibit the increased bone turnover, which can be divided into estrogen-like compounds (estrogen, oral contraceptives and selective estrogen receptor modulators [SERMs]), bisphosphonates and calcitonin; and (ii) drugs that interfere with parathyroid hormone (PTH) secretion (currently only cinacalcet is available). No drugs that interfere with PTH action are currently available. Available studies suggest that all classes of drugs are able to lower serum calcium levels. However, calcitonin does so only temporarily. Estrogen-containing compounds (hormone replacement therapy) may be less attractive because of the potential risk of breast cancer, cardiovascular disease and deep vein thromboembolism. Oral contraceptives have not been shown to be able to prevent fractures in the general population, and no data are available on their effect in women with primary hyperparathyroidism. The only SERM marketed for hyperparathyroidism is raloxifene and this has not been associated with an increased risk of breast cancer and cardiovascular diseases, and has been shown to be able to prevent vertebral fractures in postmenopausal women with osteoporosis. Two small trials suggest that raloxifene may increase bone mineral density (BMD) and decrease serum calcium levels in patients with primary hyperparathyroidism. Bisphosphonates have been shown to decrease serum calcium and increase BMD in patients with primary hyperparathyroidism, but PTH levels may increase. Cinacalcet effectively induces a sustained decrease in serum calcium and PTH for up to 1 year. However, BMD does not seem to increase. No data on hard endpoints such as fractures, kidney stones, cardiovascular disease etc. are available for any of the drugs available for the treatment of primary hyperparathyroidism.