Metamizole-induced agranulocytosis revisited: results from the prospective Berlin Case-Control Surveillance Study.

PURPOSE: Treatment with metamizole (dipyrone) has steadily increased in Germany over the last decade. The consequences of this increase for metamizole-induced agranulocytosis (MIA) are unclear. The present study addressed this topic using data from the Berlin Case-Control Surveillance Study. METHODS: Adult patients (≥18 years of age) with acute nonchemotherapy-induced agranulocytosis were identified by active surveillance in all 51 Berlin hospitals between 2000 and 2010. Cases related to metamizole were ascertained applying the drug causality criteria of the World Health Organization. The incidence rate of MIA was calculated and standardised by age and sex based on the German standard population in 2010. RESULTS: Twenty-six MIA cases out of 88 (30 %) patients with validated agranulocytosis were ascertained. The incidence of MIA was 0.96 (95 % confidence interval (CI) 0.95-0.97) cases per million per year. The median age of MIA cases was 50 years (quartile (Q)1 31 years; Q3 68 years) and 19 (73 %) of them were women. In 17 (65 %) cases, neutrophil granulocytes dropped below the value of 0.1 × 10(9) cells/L with three patients suffering from sepsis. Headache and postoperative pain were the most frequent indications for metamizole in outpatients (n = 16) and inpatients (n = 10), respectively. The median treatment duration was 6 days (Q1 4 days; Q3 19 days). CONCLUSIONS: MIA persists as a severe condition in current pharmacotherapy. The continuous increase of metamizole applications should be critically assessed, especially in regard to indications in the outpatient setting and with respect to metamizole treatment duration.

Drug-induced agranulocytosis in the Berlin case-control surveillance study.

PURPOSE: Drug-induced agranulocytosis (DIAG) is a rare but serious adverse drug reaction. The Berlin Case-Control Surveillance Study (FAKOS) aimed to identify pharmaceuticals with an increased risk for this condition. METHODS: Adult patients with acute non-chemotherapy-induced agranulocytosis, developed in hospital or in the outpatient setting, were ascertained by active surveillance in all 51 Berlin hospitals between the years 2000 and 2010. Applying the criteria of the World Health Organization, a standardized drug causality assessment was conducted for each agranulocytosis patient to determine possible drug aetiology. Drug risks were quantified in a case-control design with unconditional logistic regression analysis. RESULTS: Sixty-three out of 88 validated cases of agranulocytosis were identified as being at least probably drug-related. Drug causality assessment resulted in 36 pharmaceuticals with a certain or probable relationship to agranulocytosis. Drugs involved in ≥ 3 cases with a probable or certain causality were metamizole (dipyrone) (N = 10), clozapine (N = 6), sulfasalazine (N = 5), thiamazole (N = 5), and carbamazepine (N = 3). In case-control analysis, six drugs were identified with significant odds ratios for DIAG. The highest odds ratios were observed for clozapine, sulfasalazine, and thiamazole. CONCLUSIONS: Our findings are generally in agreement with those of earlier case-control studies. The spectrum of drugs causing acute agranulocytosis has not changed considerably over recent years, despite many newly marketed drugs. Evidence for induction of agranulocytosis by some new pharmaceuticals is supported.

Citalopram-induced bleeding due to severe thrombocytopenia.

BACKGROUND: In case reports and observational studies, serotonin reuptake-inhibitors (SSRIs) have been linked to an increased risk of bleeding, possibly due to platelet dysfunction as a consequence of serotonin-uptake blockade into platelets. OBJECTIVE: The authors propose that bleeding as a result of SSRI use may also be caused by other mechanisms. METHOD: Here, the authors report on a 32-year-old woman with hemorrhages resulting from severe drug-induced immune thrombocytopenia after 4 weeks of citalopram therapy. RESULTS: After withdrawal of citalopram and treatment with platelet concentrates and prednisolone, the patient recovered completely. CONCLUSION: As this case report shows, drug-induced immune thrombocytopenia may present another possible mechanism for bleeding in SSRI-treated patients.

Systematic review: agranulocytosis induced by nonchemotherapy drugs.

BACKGROUND: Nonchemotherapy drug-induced agranulocytosis is a rare adverse reaction that is characterized by a decrease in peripheral neutrophil count to less than 0.5 x 10(9) cells/L due to immunologic or cytotoxic mechanisms. PURPOSE: To systematically review case reports of drugs that are definitely or probably related to agranulocytosis. DATA SOURCES: English-language and German-language reports in MEDLINE (1966 to 2006) or EMBASE (1989 to 2006) and in bibliographies of retrieved articles. STUDY SELECTION: Published case reports of patients with nonchemotherapy drug-induced agranulocytosis. DATA EXTRACTION: One reviewer abstracted details about cases and assessed causality between drug intake and agranulocytosis by using World Health Organization assessment criteria. DATA SYNTHESIS: Causality assessments of 980 reported cases of agranulocytosis were definite in 56 (6%), probable in 436 (44%), possible in 481 (49%), and unlikely in 7 (1%). A total of 125 drugs were definitely or probably related to agranulocytosis. Drugs for which more than 10 reports were available (carbimazole, clozapine, dapsone, dipyrone, methimazole, penicillin G, procainamide, propylthiouracil, rituximab, sulfasalazine, and ticlopidine) accounted for more than 50% of definite or probable reports. Proportions of fatal cases decreased between 1966 and 2006. More patients with a neutrophil count nadir less than 0.1 x 10(9) cells/L had fatal complications than did those with a neutrophil count nadir of 0.1 x 10(9) cells/L or greater (10% vs. 3%; P < 0.001). Patients treated with hematopoietic growth factors had a shorter median duration of neutropenia (8 days vs. 9 days; P = 0.015) and, among asymptomatic patients at diagnosis, had a lower proportion of infectious or fatal complications (14% vs. 29%; P = 0.030) than patients without such treatment. LIMITATIONS: Case reports cannot provide rates of drug-induced complications, sometimes incompletely assess or describe important details, and sometimes emphasize atypical features and outcomes. CONCLUSIONS: Many drugs can cause nonchemotherapy drug-induced agranulocytosis. Case fatality may be decreasing over time with the availability of better treatment.