[Strontium ranelate-induced DRESS syndrome]

Prenatal developmental toxicity study of strontium citrate in Sprague Dawley rats

In this study, the pregnant female Sprague Dawley (SD) rats were used to evaluate the potential toxicological effect of strontium citrate, a dietary supplement, on embryo-fetal development. Strontium citrate at doses of 0 mg/kg, 680 mg/kg, 1360 mg/kg, and 2267 mg/kg was administrated orally by gavage to rats at day 6 to day 15 of pregnancy. Each group contained 20 pregnant rats. On the 20^th day of gestation, rats was anesthetized and dissected by cesarean section. The appearance, internal organs, gravid uterus weight, embryo implantation number, and implantation loss rate in maternal rats of each group did not reveal any lesions. In fetuses, there were no statistical differences in the fetus weight, sex ratio, embryo resorption number, stillbirth number, and fetal visceral examination in all testing groups compared to the control group. However, in 2267 mg/kg strontium citrate group, the fetuses showed the statistical differences in the anomalies of the bones and eyes compared to the control group. These findings indicate that high-dose strontium citrate possesses an adverse effect on embryonic and fetal development in SD rats. The no observed adverse effect level (NOAEL) of strontium citrate for prenatal development toxicity in SD rats may be regarded as 1360 mg/kg/day.

[DRESS syndrome and agranulocytosis, a rare combination]

INTRODUCTION

Drug reaction with eosinophilia and systemic symptoms (DRESS) is a severe toxidermia that can lead to death from multivisceral failure. We report a case of DRESS associated with febrile agranulocytosis in a child.

OBSERVATION

An 8-year-old child was hospitalized for diffuse maculopapular exanthema with edema of the extremities and face associated with cheilitis and febrile agranulocytosis. This symptomatology began 1month after the introduction of carbamazepine for partial epilepsy. The clinical picture was a multisystemic disease with colitis, interstitial pneumonitis, hepatic cytolysis, and hepatocellular insufficiency. HHV7 viral reactivation and increased eosinophils (20%) in the myelogram were demonstrated, providing the diagnosis of DRESS. The progression was favorable after carbamazepine therapy was stopped and systemic corticosteroids were administered.

DISCUSSION

DRESS syndrome is a disorder that is unfamiliar to pediatricians. Its association with agranulocytosis is rare and the absence of hypereosinophilia contributed to diagnostic difficulties in this case. The multisystemic failure, the reactivation of HHV7, the increase of eosinophils in the myelogram, and the favorable progression under systemic corticosteroid therapy contributed greatly to the diagnosis. A cutaneous biopsy was not considered necessary for the diagnosis in the case reported herein.

CONCLUSION

DRESS syndrome is rarely associated with agranulocytosis, but its diagnosis must be quickly raised so that the incriminated drug can be interrupted.

Short-term and long-term effects of osteoporosis therapies

Progress continues to be made in the development of therapeutics for fracture prevention. Bisphosphonates are now available orally and intravenously, often as inexpensive generics, and remain the most widely used interventions for osteoporosis. The major safety concern associated with the use of bisphosphonates is the development of femoral shaft stress fractures and, although rare, this adverse event affords the principal rationale for restricting bisphosphonate therapy to those individuals with femoral T-scores <-2.5, and for providing drug holidays in those individuals requiring therapy for >5 years. Newer antiresorptive therapies, in the form of denosumab and cathepsin K inhibitors, might increase efficacy and possibly circumvent some of the safety concerns associated with bisphosphonate use (for example, gastrointestinal and renal complications). The combination of teriparatide with antiresorptives markedly increases effects on BMD; new anabolic agents are also very promising in this regard. However, whether or not these changes in BMD translate into improved efficacy of fracture prevention remains to be determined. Vitamin D is important for the prevention of osteomalacia, but does not influence BMD or fracture risk in patients not deficient in vitamin D. The balance of risks and benefits of calcium supplementation is contentious, but patients should be encouraged to adhere to a balanced diet aimed at maintaining a healthy body weight. Consideration of a patient's risk of falling, and its mitigation, are also important. In this Review, I summarize the short-term and long-term effects of osteoporosis therapies.

Efficacy, effectiveness and side effects of medications used to prevent fractures

There is an increasing number of effective therapies for fracture prevention in adults at risk of osteoporosis. However, shortcomings in the evidence underpinning our management of osteoporosis still exist. Evidence of antifracture efficacy in the groups of patients who most commonly use calcium and vitamin D supplements is lacking, the safety of calcium supplements is in doubt, and the safety and efficacy of high doses of vitamin D give cause for concern. Alendronate, risedronate, zoledronate and denosumab have been shown to prevent spine, nonspine and hip fractures; in addition, teriparatide and strontium ranelate prevent both spine and nonspine fractures, and raloxifene and ibandronate prevent spine fractures. However, most trials provide little information regarding long-term efficacy or safety. A particular concern at present is the possibility that oral bisphosphonates might cause atypical femoral fractures. Observational data suggest that the incidence of this type of fracture increases steeply with duration of bisphosphonate use, resulting in concern that the benefit-risk balance may become negative in the long term, particularly in patients in whom the osteoporotic fracture risk is not high. Therefore, reappraisal of ongoing use of bisphosphonates after about 5 years is endorsed by expert consensus, and 'drug holidays' should be considered at this time. Further studies are needed to guide clinical practice in this area.

[DRESS syndrome: report of three cases]

Le syndrome d'hypersensibilité médicamenteuse ou Drug Rash with Eosinophilia and Systemic Symptoms (DRESS) est une toxidermie rare mais sévère. Nous rapportons trois observations de DRESS syndromes secondaires à la prise de carbamazipine dans deux cas et de salazopyrine dans un cas. Le délai moyen entre la prise médicamenteuse et la survenue du DRESS syndrome était de six semaines. Le médicament incriminé était arrêté d'une façon définitive dans tous les cas. Une corticothérapie par voie générale était instaurée chez tous les patients devant l'atteinte hépatique sévère. L’évolution était favorable avec disparation des lésions cutanées et normalisation du bilan hépatique. Le diagnostic du syndrome DRESS doit être évoqué devant un tableau associant une éruption fébrile et des signes systémiques faisant suite à une prise médicamenteuse. La précocité du diagnostic est fondamentale pour l'arrêt définitif des médicaments suspects. Le traitement n'est pas bien codifié mais repose actuellement sur la corticothérapie générale.

Osteoporosis treatment: focus on safety

Osteoporosis results in approximately one-half of older white women and one-third of men sustaining fractures, which cause significant disability and increased mortality. Interventions are now available which reduce fracture risk by about one-half, and there is evidence that they also reduce mortality in frail elderly by about 10%. The mechanism of this reduced mortality is unclear but it has the potential to substantially impact on the cost-benefit of osteoporosis treatment. Available treatments are generally well-tolerated. Bisphosphonates cause gastrointestinal side-effects when administered orally, and acute phase responses when given intravenously. Osteonecrosis of the jaw is overwhelmingly a problem of cancer sufferers rather than those with osteoporosis, but atypical patterns of fracture in the upper femoral shaft sometimes occur in users of these drugs, though they are very rare in comparison with the other osteoporotic fractures which these drugs prevent. Thus, the cost-benefit of bisphosphonate use is clearly positive in those with osteoporosis. In contrast, calcium supplements probably increase the risk of myocardial infarction, admissions to hospital with acute gastrointestinal complaints and risk of renal calculi, whereas their impact on fracture is marginal (about a 10% reduction). Thus, they are not cost-effective, and a balanced diet is a safer way of obtaining one's calcium requirements.

Drug rash with eosinophilia and systemic symptoms (DRESS) in patients receiving strontium ranelate

We have reviewed 47 drug rash with eosinophilia and systemic symptoms (DRESS) cases associated to strontium ranelate reported up to March 2011 to the Marketing Holder. The main signs were skin rash, fever, face oedema hypereosinophilia and liver involvement. For ten patients, persistence of DRESS symptoms was reported at the latest news obtained, and DRESS was identified as the direct cause of death in one case. The maximum incidence of DRESS associated with strontium ranelate was 1/24,112 [95 % CI (1/14,859; 1/42,194)] newly treated patients in France. Because DRESS is a severe drug reaction, the occurrence of a rash in a patient treated with strontium ranelate should lead to prompt and permanent treatment discontinuation.

INTRODUCTION

This study aims to describe cases of DRESS reported to the Marketing Authorisation Holder worldwide for patients receiving strontium ranelate by practitioner or by regulatory authorities.

METHODS

Spontaneously reported hypersensitivity events from the strontium ranelate pharmacovigilance database since marketing authorisation (2004) to March 2011 were reviewed by an expert committee. Cases of DRESS were classified as established, probable, possible or no DRESS according to expert judgement. National incidences of DRESS were estimated in relation to the number of newly treated patients.

RESULTS

Up to March 2011, 325 cases of strontium ranelate-induced hypersensitivity events were assessed from which 47 DRESS cases were confirmed. Mean age was 68.7 years and besides skin rash, the main signs and symptoms were hypereosinophilia, liver involvement, fever and face oedema. Median time to skin reaction was 33.5 days after treatment start. Most patients (62 %) recovered at the time of reporting or were recovering. For ten patients, persistence of DRESS symptoms was reported at the latest news obtained. Relapses were observed in a single case. The mortality rate was 8.5 %. The maximum incidence of DRESS associated with strontium ranelate was 1/24,112 [95 % CI (1/14,859; 1/42,194)] newly treated patients in France.

CONCLUSION

DRESS is a well-identified and characterised adverse reaction to strontium ranelate. This risk should be integrated in the risk-benefit balance evaluation of patient treatment, and the occurrence of a rash should lead to prompt and permanent treatment discontinuation with careful follow-up.