Upper gastrointestinal complications associated with NSAIDs in children

OBJECTIVE

To analyse serious upper gastrointestinal (UGI) complications associated with non-salicylate non-steroidal anti-inflammatory drugs (NSAIDs) in children.

METHODS

All serious UGI complications associated with non-salicylate NSAIDs approved in France to treat moderate pain or fever in children, spontaneously reported to the French Pharmacovigilance system or to the companies, between the launching of each study drug in France to December 31, 2000.

RESULTS

Serious UGI complications were reported in 61 children aged from 11 months to 15 years during treatment with niflumic acid (27), ibuprofen (23) and tiaprofenic acid (11). No case was reported with ketoprofen. UGI manifestations were UGI bleeding (15) and 46 gastrointestinal symptoms with endoscopic lesions i.e. gastritis (18), gastric ulcer (13), duodenal ulcer (7), duodenitis (4) and oesophageal ulcer (4). NSAID was combined with a salicylate in 36% of cases, given by the parents in self medication in 6.6% of cases and used outside its product licence in 33.8% of cases.

CONCLUSION

NSAIDs used in children for fever or moderate pain are associated with a risk of serious UGI complications which increases with length, dose and association with a salicylate.

[Methadone blood assay by the FPIA technique: application to the monitoring of patients in maintenance treatment to opiates]

A large inter-individual variability in methadone pharmacokinetics is observed in patients under maintenance treatment for major addiction to opiates. Therefore an individual dose titration of methadone is necessary, based on clinical response, i.e. symptoms of overdosage or withdrawal syndrome, but these symptoms are unspecific. However, a poor response to methadone treatment (asking for drug compliance) or the possibility of drug interactions may require the determination of methadone blood concentrations. Therapeutic drug monitoring (TDM) of those patients is performed using methadone trough blood concentrations measured by chromatography (GC or HPLC: reference methods) or by immunoassay, which gives more rapid results. A review of the literature led us to use the fluorescence polarisation immunoassay (FPIA technique) performed on a TDx-FLx analyzer. We confirmed the lack of "matrix effect" and FPIA was compared to GC-MS (gas chromatography-mass spectrometry) on patients samples. According to the literature, a methadone trough serum concentration target of 400 ng/mL is recommended; results under 100 ng/mL are considered as clinically ineffective, whereas methadone concentrations above 1000 ng/mL are frequently associated with drug toxicity. The linearity domain of the technique stays between 50 and 500 ng/mL, which is satisfactory. We describe some clinical cases from the Methadone Treatment Center of Tours (Centre Port-Bretagne), which showed that methadone blood concentration measurement may be helpful to achieve the optimal dose of methadone in each patient.

La soumission chimique: une revue de la littérature

The aim of this review is to describe the present knowledge about chemical submission. The number of scientific publications on this phenomenon has increased over the last 10 years. Perpetrators choose drugs which act rapidly, produce desinhibition, sedation, and anterograde amnesia during the abuse. Ethanol and benzodiazepines are the most frequently used. A few drugs, including flunitrazepam and gamma-hydroxybutyric acid (GHB), have received widespread media coverage. Toxicological investigations on blood, urine or hair samples allow to detect the substance used. Every effort should be made to collect appropriate specimens as quickly as possible. Gas chromatography-mass spectrometry is at present the most appropriate analytical method to detect these drugs in a biological specimen.

Pharmacovigilance des vaccins

Safety of vaccines must be excellent to make vaccine's strategy acceptable, since it usually has a deferred individual benefit but immediate adverse drug reactions (ADRs). Pharmacovigilance of vaccines after their marketing is crucial because, prior to its availability on the market, the size of clinical trials is insufficient to identify rare or deferred adverse effects. The Pharmacovigilance is based on "spontaneous reporting" of ADRs to the Pharmacovigilance Regional Centre (PVRC) which establishes a relationship between each drug taken by the patient and the ADRs occurrence (imputability). This method is crucial to generate alerts, but under-estimates the real frequency of ADRs (1 to 10% of severe ADRs are reported). Thus pharmacoepidemiology studies are necessary to confirm the alerts identified by spontaneous reporting. ADRs can be specific, related to the antigen of an attenuated alive virus vaccine (lymphocyte meningitis after anti-mumps vaccine) or non-specific, related to a component different from the antigen (aluminium hydroxide involved in the "macrophagic myofasciitis", allergic reactions to neomycin, latex, egg or gelatine). Importance of Pharmacovigilance of vaccines is illustrated. Data, especially case-control studies, about the relationship between multiple sclerosis and hepatitis B vaccine are summarised. Data about the relationship between Crohn's disease or autism and MMR vaccine are analysed. As vaccines are used in healthy people, their safety must be excellent to be accepted. To monitor them after their marketing is the unique way to detect rare ADRs. This surveillance is made through reporting of ADRs to the PVRC. However, an active and intensive surveillance of ADRs as the one set up from the marketing of Prevenar should be systematic.

L'enfant et les médicaments : application à la prescription en pédiatrie

Because of a lack in drug evaluation in children, they receive many off license drugs prescription, which means drugs prescribed in an indication, dosage, formulation or age different from the license terms. However, drug evaluation is crucial in paediatrics population because of pharmacokinetics and pharmacodynamics modifications throughout organism development, which make usually wrong any extrapolation to children of data obtained in adults. Drug safety is generally better in infants except in newborns who are at a particularly high drug-related risk because of high frequency of off license drug use, many drugs association and drugs metabolism immaturity. The lack of evaluation in children, the fact that children are the unique target population of some drugs or the maturation phenomena explain some adverse effects more specific in children. The more the children are young, the more they are exposed to medication or drug utilization errors. Physician must take what the SPC, as found in the Vidal dictionary, mentions about children into account while prescribing. Drugs with a paediatric license must be preferred overall, however it should be kept in mind that a paediatric license means only that the drug is active in the indication of the license but it doesn't position it regarding other therapeutic alternatives. Off labeling prescription should be based on a supposed benefit, which had to be justified if a severe side effect occurred.

Implanon® : difficultés d'insertion et de retrait, échecs contraceptifs

OBJECTIVE

Analysis of the results of a national pharmacovigilance study on Implanon, a contraceptive implant containing 68 mg of etonogestrel.

PATIENTS AND METHODS

This survey concerns cases of pregnancies (contraception failures), of migrations and of insertion or removal problems with Implanon reported to French Regional Drug Pharmacovigilance Centres and to Organon SA between May 2001 and September 2002.

RESULTS

In France, 39 unintended pregnancies were reported over 17 months. The pregnancies were in 77% of cases (N = 30) due to an insertion technique error (implant not found when pregnancy has been diagnosed). For 3 patients (7,6%), pregnancy was due to a failure of etonogestrel contraceptive effect, explained twice by its association with an enzymatic inductor drug. For 4 patients (10%), pregnancy was due to an untimely insertion (insertion after day 5 of menstrual cycle or woman already pregnant). For two patients, no information was available. The incidence of reported pregnancies in France is estimated at 0.359 / 10(3) implants [0.246-0.482], in accordance with a typical Pearl Index of 0.06 [0.04-0.08]. Twenty-eight suspected migrations (N = 11), problems or failures in removal of the implant (N = 11) and insertion difficulties (N = 6) were notified, corresponding to an incidence of 0.257/10(3) implants [0.162-0.363].

DISCUSSION AND CONCLUSION

Occurrence of pregnancy is possible with Implanon, due to errors in the insertion technique (device not really inserted) or to a non-respect of the SPC recommendations (drug-drug interaction or untimely insertion). Insertion problems can lead to localisation problems (implant not visible by X-ray) then needing further tests and even harmful practice (removal under general anaesthesia). That is why a real and strict training is highly recommended to physicians.

Retentissement néonatal de l'exposition aux benzodiazépines en fin de grossesse

INTRODUCTION

Since benzodiazepines (BZD) are largely prescribed during pregnancy, the Regional Pharmacovigilance Center (RPVC) of Tours regularly deals with questions about the risk of their administration to pregnant women and the monitoring of the newborns exposed in utero to these drugs. During the third trimester, we recommend a switch in the BZD maternal treatment to oxazepam, which has an intermediary half-life and no active metabolite, and a hospitalisation of the newborn in order to monitor his respiratory rate. The purpose of our study was to evaluate the neonatal consequences of BZD used at the end of pregnancy and to analysed if our recommendations were taken into account and if they were appropriate.

METHODS

From 1989 to the end of 2002, we studied the files in which women had received a BZD during the 30 days prior to delivery. We analysed maternal treatments, the outcome of pregnancy and the development of the newborn, the therapeutically attitude recommended and whether or not it was respected.

RESULTS

A total of 73 files were selected. Seventy neonates were born to 73 women. The newborns were hospitalised (73%) and they developed adverse reactions possibly related to the use of BZD (51,5%) : an impregnation syndrome (42%) characterized by hypotonia and hypoventilation, and a withdrawal syndrome (20%) with tremulations as the main symptom.

CONCLUSION

Considering the most frequent neonatal manifestations, hospitalization and the respiratory monitoring recommended by the RPVC seemed adequate. However, the switch to oxazepam was seldom done and its advantages should be pointed out.

[Isotretinoin: compliance with recommendations in childbearing women]

INTRODUCTION

The aim of this survey is to ascertain if the incidence of isotretinoin exposed pregnancies was reduced by the late recommendations of prescription and issue (AMM modification on 06/08/2001 and 25/09/2001).

METHODS

All isotretinoin exposed pregnancies registered by the French Regional Drug Monitoring Centres, the Information Centre for Teratogenic Agents and Roche (Roaccutane), Pierre Fabre (Curacné Gé) and Expanscience (Procuta Gé) laboratories, from January 1st, 1999 to December 31st, 2002, were analysed. Enforcement of the strengthening of isotretinoin prescription recommendations was analysed on a sample of 68 prescriptions from 45 pharmacies throughout France.

RESULTS

In 4 years, 103 isotretinoin exposed pregnancies (Roaccutane 97 p. 100, Curacné(R) Gé 3 p. 100) during teratogenic risk period, were registered. Pregnancy started less than one month after isotretinoin stopping (37 p. 100), during the treatment (43 p. 100), or was in progress when the treatment was initiated (20 p. 100). The reason of the 22 lacking contraception was known 12 times, i.e. an absence of prescription (6 times), a refusal to take a prescribed contraception (3 times) and a self-medication (3 times). Among the 71 pregnancies whose contraceptive status is known, 48 p. 100 could had been avoided if recommendations had been followed (pregnancies due to a premature stopping or an absence of contraception). The issue of pregnancies is a voluntary termination in 60 cases (87 p. 100). Malformations frequency is 25 p. 100. Incidence of isotretinoin exposed pregnancies remained stable, 0.26/1000 treated women (vs 0.34 after 2001's AMM modifications). Of 68 prescriptions studied, 23 (24 p. 100) carried all the legal warnings, which is close to the previous survey's results. Contraception was in accordance with the recommendations in 78 p. 100 of cases and women learned and applied information given in 38 p. 100 of cases. At last, only 6 patients (9 p. 100) have both a correctly written prescription, a contraception and a time between the pregnancy test date and prescription and issue dates, in accordance with the licence and have had a correct information and understood it. Regarding the previous survey, pregnancy test before treatment was more often prescribed (96 p. 100 vs 88 p. 100). On the other hand, less women knew the necessity to keep on taking contraception one month after isotretinoin stopping (82 p. 100 vs 93 p. 100).

CONCLUSION

Despite 3 successive isotretinoin prescription and issue recommendations strengthening in childbearing women, pregnancies can't be totally avoided. Bad compliance concerns the prescription and/or an incomplete or not understood information by the patient who does not scrupulously apply the care and contraception agreement. However, this study does not allow to assess the proportion of issued prescriptions despite their non-accordance with the licence criteria. The National Commission of Pharmacovigilance did not like to limit isotretinoin prescription to dermatologists only. It estimates that the administrative authority must intensify information by dermatologists, general practitioners and pharmacists, about measures to take to avoid an exposure to isotretinoin during pregnancy.

Exposition aux antidépresseurs inhibiteurs de la recapture de la sérotonine (IRS) en fin de grossesse : retentissement néonatal

OBJECTIVES

To analyse neonatal effects after in utero selective serotonin reuptake inhibitors exposure and the pertinence of recommendations delivered by our team.

MATERIALS AND METHODS

We report a series of 27 pregnancies exposed late in pregnancy including the period of delivery, to the Selective Serotonin Reuptake Inhibitors (SSRI) and having been the subject of a call to the Regional Center of Pharmacovigilance of Tours (CRPV).

RESULTS

Twenty-seven children were born without malformation. Twelve children were hospitalized because of prematurity (two), exposure to other drugs imposing particular surveillance (eight) or in view of abnormal neonatal effects (two). Five newborns (18.5%) of which three had also been exposed to other drugs (benzodiazepine, neuroleptic, H1-antagonist) had presented one or more neonatal adverse effects compatible with the role of the SSRI (irritability, agitation, shivering, hypotonia) but with uncertainty about a clear discrimination between withdrawal syndrome and serotonin impregnation. All the symptoms disappeared spontaneously. One of the five children had a described in treated adults but two neonatal observations were published. No child had hemorrhagic symptoms as described in treated adults despite the fact that two neonatal observations were reported.

CONCLUSION

This study confirms the relative benignity of SSRI exposure during late pregnancy. Our recommendations for monitoring the newborns during their stay in maternity wards were well respected. The risk of hemorrhagic symptoms or hyponatremia, not well known by pediatricians, deserves to be recalled to medical teams who take in charge newborns exposed to SSRI.

Bayesian estimation of cyclosporin exposure for routine therapeutic drug monitoring in kidney transplant patients

AIMS

AUC-based monitoring of cyclosporin A (CsA) is useful to optimize dose adaptation in difficult cases. We developed a population pharmacokinetic model to describe dose-exposure relationships for CsA in renal transplant patients and applied it to the Bayesian estimation of AUCs using three blood concentrations.

METHODS

A total of 84 renal graft recipients treated with CsA microemulsion were included in this study. Population pharmacokinetic analysis was conducted using NONMEM. A two-compartment model with zero-order absorption and a lag time best described the data. Bayesian estimation was based on CsA blood concentrations measured before dosing and 1 h and 2 h post dose. Predictive performance was evaluated using a cross-validation approach. Estimated AUCs were compared with AUCs calculated by the trapezoidal method. The Bayesian approach was also applied to an independent group of eight patients exhibiting unusual pharmacokinetic profiles.

RESULTS

Mean population pharmacokinetic parameters were apparent clearance 30 l h(-1), apparent volume of distribution 79.8 l, duration of absorption 52 min, absorption lag time 7 min. No significant relationships were found between any of the pharmacokinetic parameters and individual characteristics. A good correlation was obtained between Bayesian-estimated and experimental AUCs, with a mean prediction error of 2.8% (95% CI [-0.6, 6.2]) and an accuracy of 13.1% (95% CI [7.5, 17.2]). A good correlation was also obtained in the eight patients with unusual pharmacokinetic profiles (r(2) = 0.96, P < 0.01).

CONCLUSIONS

Our Bayesian approach enabled a good estimation of CsA exposure in a population of patients with variable pharmacokinetic profiles, showing its usefulness for routine AUC-based therapeutic drug monitoring.

Exposition aux bêtabloquants en fin de grossesse

OBJECTIVES

To analyse neonatal effects after in utero betablockers exposure and the pertinence of recommendations delivered by our team.

POPULATION AND METHODS

We report 44 pregnancies exposed to betablockers during the late pregnancy including the period of delivery about which the Regional Pharmacovigilance Center of Tours (CRPV) was questionned.

RESULTS

Among the 39 children for whom we know the follow up, 22 had neonatal adverse effects of which 19 could be explained by in utero exposure to betablockers i.e. an hypoglycaemia (11 times), a bradycardia (six times), a bradycardia and hypoglycemia (one time) and an hypotension (one time). A drug-related effect was retained for eleven newborns (27%) and another etiology could be evoked in the eight others. The risk of neonatal adverse effects seems to increase in newborns exposed to labetalol (5/11), to betaxolol (1/2) or to propranolol (2/6) or when the dose is high. The eight newborns who had intrauterine growth retardation were generally more often exposed to atenolol than eutrophic newborns. Four babies had malformations.

CONCLUSIONS

Our recommendation was an hospitalization 44 times (100%) to monitor heart rate, blood pressure and glycemia. When the follow-up is known, hospitalization was performed in 88% of the cases. Glycemia, heart rate and blood pressure were monitored in all the hospitalized children and in three of the five not hospitalized children. Our recommendation seems particularly justified with regard to hypoglycemia which is often asymptomatic but whose consequences can be severe. Atenolol often provider of intrauterine growth retardation and labetalol more often at the origin of neonatal adverse effects are probably to avoid during pregnancy.