Ugo Moretti

Adverse drug reactions related to the use of fluoroquinolone antimicrobials: an analysis of spontaneous reports and fluoroquinolone consumption data from three italian regions.

AbstractObjective: To analyse and compare with one another and with other antibacterial drugs the adverse drug reactions (ADRs) of the different fluoroquinolones currently used in Italy, spontaneously reported from doctors in three northern Italian regions. Methods: The data on fluoroquinolones and other antibacterials were obtained from the spontaneous reporting system database of Emilia Romagna, Lombardy and the Veneto, which are the principal contributors to the Italian spontaneous surveillance system. The fluoroquinolone ADRs with a causality assessment of certain, probable or possible (according to WHO criteria), reported between January 1999 and December 2001, were selected and toxicity profiles of individual drugs were described and compared with one another. The reports were also correlated with sex and age of patients and with regional prescription data to estimate individual fluoroquinolone reporting rate of adverse events. Results: During the study period, 10 011 reports were received by the system (a mean annual reporting rate of approximately 185 per million inhabitants): 1920 referred to systemic antimicrobials, of which 432 (22.5%) involved fluoroquinolones.Pefloxacin was associated with the highest reporting rate (982 reports/daily defined dose/1000 inhabitants/day), followed by moxifloxacin (356), rufloxacin (221) and lomefloxacin (196). The most frequently reported reactions to fluoroquinolones involved the skin, but their percentage (25%) was significantly lower (p < 0.01) than those of other systemic antimicrobials (58.5%), whereas the percentages of reactions involving the central nervous (12.2 vs 3.6%), musculoskeletal (14.7 vs 0.3%) and psychiatric systems (9.3 vs 1.8%) were significantly higher (p < 0.01). We found some significant differences in the safety profiles of individual fluoroquinolones: ciprofloxacin was more frequently associated with skin reactions (p < 0.01), levofloxacin and pefloxacin with musculoskeletal (p < 0.01), and rufloxacin with psychiatric disorders (p < 0.05). Levofloxacin was the fluoroquinolone associated with the highest rate of serious tendon disorders; phototoxic reactions were more frequent with lomefloxacin, and toxic epidermal necrolysis and Stevens-Johnson syndrome were seen only with ciprofloxacin. Conclusions: The differences in the safety profiles should be taken into account when prescribing a fluoroquinolone to individual patients.

Drug-induced torsades de pointes: data mining of the public version of the FDA Adverse Event Reporting System (AERS).

To investigate spontaneous reports of TdP present in the public version of the FDA Adverse Event Reporting System (AERS) in the light of what is already known on their TdP‐liability.

Antimicrobials and the Risk of Torsades de Pointes: The Contribution from Data Mining of the US FDA Adverse Event Reporting System

AbstractBackground: Drug-induced torsades de pointes (TdP) is a complex regulatory and clinical problem due to the rarity of this sometimes fatal adverse event. In this context, the US FDA Adverse Event Reporting System (AERS) is an important source of information, which can be applied to the analysis of TdP liability of marketed drugs. Objective: To critically evaluate the risk of antimicrobial-induced TdP by detecting alert signals in the AERS, on the basis of both quantitative and qualitative analyses. Methods: Reports of TdP from January 2004 through December 2008 were retrieved from the public version of the AERS. The absolute number of cases and reporting odds ratio as a measure of disproportionality were evaluated for each antimicrobial drug (quantitative approach). A list of drugs with suspected TdP liability (provided by the Arizona Centre of Education and Research on Therapeutics [CERT]) was used as a reference to define signals. In a further analysis, to refine signal detection, we identified TdP cases without co-medications listed by Arizona CERT (qualitative approach). Results: Over the 5-year period, 374 reports of TdP were retrieved: 28 anti-bacterials, 8 antifungals, 1 antileprosy and 26 antivirals were involved. Antimicrobials more frequently reported were levofloxacin (55) and moxi-floxacin (37) among the antibacterials, fluconazole (47) and voriconazole (17) among the antifungals, and lamivudine (8) and nelfinavir (6) among the antivirals. A significant disproportionality was observed for 17 compounds, including several macrolides, fluoroquinolones, linezolid, triazole antifungals, caspofungin, indinavir and nelfinavir. With the qualitative approach, we identified the following additional drugs or fixed dose combinations, characterized by at least two TdP cases without co-medications listed by Arizona CERT: ceftriaxone, piperacillin/tazobactam, cotrimoxazole, metronidazole, ribavirin, lamivudine and lopinavir/ritonavir. Discussion: Disproportionality for macrolides, fluoroquinolones and most of the azole antifungals should be viewed as ‘expected’ according to Arizona CERT list. By contrast, signals were generated by linezolid, caspofungin, posaconazole, indinavir and nelfinavir. Drugs detected only by the qualitative approach should be further investigated by increasing the sensitivity of the method, e.g. by searching also for the TdP surrogate marker, prolongation of the QT interval. Conclusions: The freely available version of the FDA AERS database represents an important source to detect signals of TdP. In particular, our analysis generated five signals among antimicrobials for which further investigations and active surveillance are warranted. These signals should be considered in evaluating the benefit-risk profile of these drugs.

Epidemiology and characteristics of adverse drug reactions caused by drug–drug interactions

Introduction: Drug–drug interactions (DDIs) arise in numerous different ways, involving pharmacokinetic or pharmacodynamic mechanisms. Adverse drug reactions are a possible consequence of DDIs and health operators are often unaware of the clinical risks of certain drug combinations. Many papers on drug interactions have been published in recent years, but most of them focused on potential DDIs while few studies have been conducted on actual interactions. Areas covered: This paper reviews the epidemiology of actual DDIs in outpatients as well as in hospital settings and in spontaneous reporting databases. The incidence of actual DDIs is consistently lower than that of potential DDIs. However, the absolute number of patients involved is high, representing a significant proportion of adverse drug reactions. The importance of risk factors such as age, polypharmacy and genetic polymorphisms is also evaluated. The relevance and efficacy of tools for recognizing and preventing DDIs are discussed. Expert opinion: Potential DDIs far outnumber actual drug interactions. The potential for an adverse interaction to occur is often theoretical, and clinically important adverse effects occur only in the presence of specific risk factors. Several studies have shown the efficacy of computers in early detection of DDIs. However, a correct risk–benefit evaluation by the prescribing physician, together with a careful clinical, physiological and biochemical monitoring of patients, is essential. Future directions of drug interaction research include the increasing importance of pharmacogenetics in preventing DDIs and the evaluation of interactions with biological drugs.

Identifying Adverse Drug Reactions Associated with Drug-Drug Interactions: Data Mining of a Spontaneous Reporting Database in Italy

AbstractBackground: Drug-drug interactions (DDIs) are an important cause of adverse drug reactions (ADRs). Many studies have recently considered this issue, but most of them focus only on potential interactions and are often related to the hospital setting. A spontaneous reporting database could be a valuable resource for detection of ADRs associated with DDIs; however, data in the literature are limited. Objective: To detect those patients treated with potentially interacting drugs and the cases where reported adverse reactions are a possible consequence of DDIs, using an Italian spontaneous reporting database. Methods: The data were obtained from a database containing all reports of suspected ADRs from five Italian regions (January 1990 to December 2007) that are the main contributors to the Italian spontaneous reporting system. All reports containing at least two drugs, reported as being suspected of causing the ADR or as concomitant medication, were selected and a list of drug pairs was drawn up. We performed a search to verify which drug pairs are considered a potential DDI, using the Internet version of the DRUGDEX® system. For each report containing a potential DDI, we verified whether the description of the adverse reaction corresponded to the interaction effect. Results: The database contained 45 315 reports, of which 17 700 (39.1%) had at least two reported drugs. We identified 5345 (30.2%) reports with potential DDIs, and in 1159 (21.7%) of these reports a related ADR was reported. The percentage of reports with potential DDIs increased in relation to the number of concomitantly administered drugs, ranging from 9.8% for two drugs to 88.3% for eight or more drugs. The percentages of serious or fatal reports of ADRs associated with a DDI were significantly higher than other reports analysed. The mean age, percentage of male patients and the mean number of drugs were also significantly higher in reports with DDIs than in other reports. In 235 of 1159 reports (20.3%), both interacting drugs were recognized as suspect by the reporter. This percentage varies in relation to the drugs involved, ranging from 2% to about 65%. The most frequently reported interaction was digoxin and diuretics, but no fatal ADRs were reported with this combination. The combination of anticoagulant and antiplatelet agents was responsible for the greatest number of serious reactions and deaths. Conclusions: This study validates that spontaneous reporting, despite its limitations, can be an important resource for detecting ADRs associated with the concomitant use of interacting drugs. Moreover, our data confirm that DDIs could be a real problem in clinical practice, showing that more than one in five patients exposed to a potential DDI experienced a related ADR.

Drug-induced anaphylaxis : case/non-case study based on an italian pharmacovigilance database.

AbstractObjective: To identify the number of cases of anaphylaxis reported in association with different classes of drugs and compare it with other reports contained in the same database. Methods: The data were obtained from a database containing all of the spontaneous reports of adverse drug reactions (ADRs) coming from the Italian regions of Emilia Romagna, Lombardy and the Veneto, which are the main contributors to the Italian spontaneous surveillance system. The ADRs reported between January 1990 and December 2003 with a causality assessment of certainly, probably or possibly drug related (according to the WHO criteria) were analysed using a case/non-case design. The cases were defined as the reactions already coded by the WHO preferred terms of ‘anaphylactic shock’ or ‘anaphylactoid reaction’ (this last term also included anaphylactic reaction) and those with a time of event onset that suggested an allergic reaction and involved at least two of the skin, respiratory, gastrointestinal, CNS or cardiovascular systems; the non-cases were all of the other ADR reports. The frequency of the association between anaphylaxis and the suspected drug in comparison with the frequency of anaphylaxis associated to all of the other drugs was calculated using the ADR reporting odds ratio (ROR) as a measure of disproportionality. Results: Our database contained 744 cases (including 307 cases of anaphylactic shock with 10 deaths) and 27 512 non-cases. The percentage of anaphylaxis cases reported in inpatients was higher than that among outpatients (59.1% vs 40.9%). This distribution is significantly different from that of the other ADR reports that mainly refer to outpatients. After intravenous drug administrations, anaphylactic shock cases were more frequent than anaphylactoid reactions or other ADRs, but more than one-third of these reactions were caused by an oral drug. Blood substitutes and radiology contrast agents had the highest RORs. Among the systemic antibacterial agents, anaphylaxis was disproportionally reported more often for penicillins, quinolones, cephalosporins and glycopeptides, but diclofenac was the only NSAID with a significant ROR. As a category, vaccines had a significantly lower ROR, thus indicating that anaphylaxis is reported proportionally less than other ADRs. Conclusions: Anaphylaxis is a severe ADR that may also occur with commonly used drugs. It represents 2.7% of all of the ADRs reported in an Italian spontaneous reporting database.

Statin-associated psychiatric adverse events: a case/non case evaluation of an Italian database of spontaneous adverse drug reaction reporting

AbstractBackground: The inhibitors of HMG-CoA reductase (‘statins’) are widely prescribed hypolipidaemic drugs, which have been evaluated in several clinical trials involving hundreds of thousands of patients. From a safety perspective, both clinical trials and post-marketing surveillance have demonstrated that statins are generally well tolerated, with rare serious adverse drug reactions (ADRs) that affect mainly muscle, liver and kidney. However, recent interest has been focused on a potential risk of psychiatric ADRs associated with statins, including memory loss, depression, suicidality, aggression and antisocial behaviour. Special attention is currently being paid to the potential for statin-induced sleep disorders. Objective: To investigate the hypothesis that statins may be associated with psychiatric adverse events using quantitative and qualitative signal analysis. Methods: The Interregional Group of Pharmacovigilance database holds reports of suspected ADRs submitted since 1988 from eight Italian regions. In the present analysis, only reports ranked at least ‘possible’, according to WHO causality assessment criteria, were considered. Association between statins and psychiatric events was assessed by the case/non-case methodology, calculating the ADR reporting odds ratio (ROR) as a measure of disproportionality. Cases were defined as patients with at least one reported ADR combined with the system organ class (SOC) ‘psychiatric disorders’. The non-cases comprised all patients who did not experience an ADR related to the SOC ‘psychiatric disorders’. Index reports comprised all ADR reports involving at least one statin, while all ADR reports not involving statins as suspected drugs were used as controls. Results: According to selection criteria, 35 314 reports were included in the analysis. A total of 71 psychiatric preferred terms combined with statins were identified in 60 reports. Among them, 14 reports (23.3%) noted a positive rechallenge. Both the unadjusted (0.8; 95% CI 0.6, 1.1) and adjusted ROR (0.7;95% CI 0.6, 1.0) suggested a lower rate of reports of psychiatric events for statins as a whole class compared with all other drugs, although the difference was not significant. The five most frequently reported psychiatric events combined with statins were insomnia, somnolence, agitation, confusion and hallucination. Only insomnia was reported with higher frequency for statins compared with all other drugs (ROR = 3.3; 95% CI 1.9, 5.7), while confusion was reported with a lower frequency (ROR = 0.4; 95% CI 0.1, 0.9). Amongst statins available in Italy, only simvastatin (ROR = 0.5; 95% CI 0.2, 0.9) showed a significantly lower rate of reports of psychiatric events compared with all other drugs together. Conclusion: A relatively small number of possible statin-associated psychiatric ADRs have been found in our database. No significant risks for a higher overall reporting of psychiatric ADRs associated with statins were identified in comparison with all other drugs combined. However, statin-associated insomnia resulted in a significant ROR that requires further investigation.

Drug-related deaths: an analysis of the Italian spontaneous reporting database.

AbstractBackground: Adverse drug reactions (ADRs) represent a major public health concern, with death as the ultimate adverse drug outcome. Despite the relevance of this, the frequency of fatal ADRs (FADRs) is to a large extent unknown. Although spontaneous reporting data cannot give an exact estimate of the magnitude of drug-related mortality, it may highlight the importance and large dimensions of this public health problem. Objective: To describe the types and pattern of reported FADRs by analysing data from the national spontaneous reporting system in Italy. Methods: The Italian Medicines Agency (AIFA) runs a pharmacovigilance database where all the individual case safety reports (since January 2001) are stored. We selected and then analysed in detail all the case reports (to the end of December 2006) in which death was reported as the outcome. We included in the study only FADR case reports with a probable or possible causality assessment, according to the criteria established by the WHO. In line with the Italian reporting form, we divided FADR reports into two groups: (i) suspected ADRs that caused death; and (ii) suspected ADRs that contributed to death. Results: In the AIFA database 38 507 suspected ADR case reports were collected, of which 641 (1.66%) had a fatal outcome. We analysed 450 case reports (1.17% of total reports), 159 (35.33%) of them causing the patient’s death and 291 (64.67%) contributing to death. The annual percentage of FADR reports followed a constant trend during the 6-year period. The majority of fatal reports (79%) were sent by hospital doctors. In total, 222 different drugs were suspected as causes of FADRs. ‘Systemic anti-infective drugs’ was the drug category associated with the highest percentage of FADRs (21.9%), followed by antineoplastic and immunomodulating agents (18.8%), and then by nervous system drugs (14.8%). Other drug categories involved in the fatal case reports were antithrombotic agents, NSAIDs and contrast media. Conclusions: The drugs most frequently involved in FADRs were drugs of wide usage with a narrow therapeutic range or those that caused serious skin or systemic allergic reactions. Ceftriaxone, ticlopidine and nimesulide were associated with the highest number of fatal case reports; the related FADRs were already known and recognized for each of these drugs. We highlight some cases reflecting probable inappropriate drug use by Italian physicians. This suggests a need for continued clinical pharmacology training and that many FADRs might be preventable through better medical and prescribing practice.

Adverse drug reactions related to the use of NSAIDs with a focus on nimesulide: results of spontaneous reporting from a Northern Italian area.

AbstractObjective: To analyse and compare the adverse drug reactions (ADRs) associated with the use of nimesulide with those associated with diclofenac, ketoprofen, and piroxicam, reported spontaneously in a northern Italian area (Veneto and Trentino). Methods: Data were obtained from the spontaneous reporting system database of Veneto-Trentino, the principal contributor to the Italian spontaneous surveillance system. All case reports that occurred in association with all formulations of the nonsteroidal anti-inflammatory drugs (NSAIDs) under investigation during the period from January 1988 to December 2000, were analysed in detail.Sales data from June 1996 to May 1999 and prescription data, from 1997 to 2000 from the Veneto region were utilised to select the most widely used NSAIDs to be included in the study. The prescription data were also used to look at the drug use in relation to age. Results: During the study period, 10 608 reports describing 16 571 adverse reactions were entered into the surveillance system. We found 207 case reports for nimesulide, 187 for diclofenac, 174 for ketoprofen, and 137 for piroxicam. Analysis of sales and prescription data revealed that in the Veneto region nimesulide was the most widely prescribed drug followed at a long distance by diclofenac, piroxicam and ketoprofen.No age-related difference in the use of the four drugs was found. Analysis of the case reports revealed significantly different toxicity profiles for the four drugs. In particular, nimesulide was associated with fewer and less severe gastrointestinal (GI) ADRs compared with the other NSAIDs. Nimesulide was associated with about half the number of GI reactions (10.4%) than the other three NSAIDs (21.2% for diclofenac, 21.7% for ketoprofen, 18.6% for piroxicam). Two previously unreported reactions were also found for piroxicam and ketoprofen. Conclusions: Nimesulide is the most frequently used NSAID in Italy. Spontaneous reporting data suggest that nimesulide has the most favourable GI tolerability profile of the NSAIDs investigated, with few reports of severe GI reactions. A few reports of hepatic and renal impairment associated with nimesulide suggest caution in patients at risk. Age-related reporting analysis suggests a higher toxicity for diclofenac and piroxicam in the elderly compared with nimesulide and ketoprofen.This analysis of the Veneto-Trentino database on spontaneous reporting confirms that NSAIDs differ in their tolerability profile, and this fact should be taken into account in the choice of drugs in relation to patient characteristics.

Influence of regulatory measures on the rate of spontaneous adverse drug reaction reporting in Italy.

AbstractBackground: The reporting of adverse drug reactions (ADRs) is the mainstay of post-marketing surveillance systems. Under-reporting and selective reporting are considered the main limitations of a spontaneous reporting-based pharmacovigilance system. However, excessive reporting induced by external events may also impair signal detection by increasing the noise level. Objective: The aim of this study was to examine the influence of regulatory measures and other external factors on the rate of ADR reporting in Italy, focusing on four situations occurring in the last 10 years: ACE inhibitor-induced cough; HMG-CoA reductase inhibitors (‘statins’) and rhabdomyolysis; nimesulide and hepatic toxicity; and cyclo-oxygenase (COX)-2 selective inhibitors (‘coxibs’) and increase in cardiovascular risk. Methods: The study was based on data from spontaneous reporting in six Italian regions collected from January 1995 to December 2005. We analysed a 10-year period as a reasonable time interval around the four situations of interest, highlighting the influence of regulatory measures on the rate of ADR reporting (number of reports per million inhabitants). Chi-squared tests were used to assess the statistical significance of any changes in ADR reporting. Drug sales data were also studied to examine possible changes in drug use. Sales data were expressed as daily defined dose per 1000 inhabitants per day. Results: ACE inhibitors: a 5-fold increase in the reporting rate of ACE inhibitor-induced cough was observed in 1998 and 1999 following a restriction on reimbursement for angiotensin receptor blockers introduced in 1998 and removed at the end of 1999. Statins: after the withdrawal of cerivastatin in 2001, the ADR reporting rate increased more than 4-fold, with musculoskeletal ADRs representing about 60% of all the ADRs reported in that year, and progressively decreased in the following years. Nimesulide: an increase in hepatic ADR reporting was observed after withdrawal of the drug from the Finnish and Spanish markets in 2002. Coxibs: no important changes in the rate of cardiovascular events reporting in the period 2000–4 were observed. In 2005, after the withdrawal of rofecoxib in September 2004, both the ADR reporting rate and sales of the drug decreased drastically. Conclusion: Our data suggest that spontaneous ADR reporting can be influenced in different ways by external events. Our data emphasize the need for educational initiatives aimed at increasing the doctor’s and patient’s awareness of the usefulness and the limitations of spontaneous reporting in the pharmacovigilance system. Such initiatives should use appropriate risk communication strategies in order to avoid unnecessary alarm, which could cause unjustified interruption of therapies or misplaced confidence in new drugs.