Pemoline hepatotoxicity in children

A Review of Methods for Monitoring Adverse Events in Pediatric Psychopharmacology Clinical Trials

Pediatric psychotropic prescription rates are rising, emphasizing the need for careful monitoring of drug safety in this population. Currently, no standardized assessments are used in clinical trials for adverse event (AE) elicitation focused on long-term drug treatment in pediatric patients. Despite a lack of standardized AE elicitation methods in psychiatric clinical trials, it is clear that psychiatric medications have developmentally dependent AEs that differ from those observed in adults. In this review, we discuss the use of general inquiry elicitation, drug-specific checklists, and systematic elicitation scales for AE reporting in pediatric psychopharmacology trials. The checklists evaluated include the Barkley Side Effect Rating Scales (SERS), the Pittsburg side effect rating scale, and the Systematic Monitoring of Adverse events Related to TreatmentS (SMARTS) checklist. The systematic assessment scales discussed include the Systematic Assessment for Treatment of Emergent Events (SAFTEE) and the Safety Monitoring Uniform Report Form (SMURF). We review the advantages and disadvantages of each method and discuss the need for optimal assessment of AEs. AE instruments that are created and utilized for pediatric psychiatric trials must begin to incorporate symptoms that are relevant to this population and account for the nature of the disorders to better characterize treatment-emergent AEs and monitor long-term safety.

Age-related differences in reporting of drug-associated liver injury: data-mining of WHO Safety Report Database

BACKGROUND/AIMS

Age-differences in the frequency and manifestations of drug-induced liver injury are not fully characterized. Data-mining analyses were performed to assess the impact of age on liver event reporting frequency with different phenotypes and agents.

METHODS

236 drugs associated with hepatotoxicity were evaluated using the Empirical Bayes Geometric Mean (EBGM) of the relative reporting ratio with 90% confidence interval (EB05 and EB95) calculated for the age groups: 0-17, 18-64, and⩾65years (or elderly), for overall, serious (acute liver failure), hepatocellular, and cholestatic liver injury, using the WHO Safety Report Database.

RESULTS

Overall, cases of age 0-17, 18-64, and 65years or older comprised 6%, 62%, and 32% of liver event reports. Acute liver failure and hepatocellular injury were more frequently reported among children compared to adults and the elderly while reports with cholestatic injury were more frequent among the elderly (p<0.00001). A potential to cause mitochondrial dysfunction was more prevalent among the drugs with increased pediatric reporting frequency while high lipophilicity and biliary excretion were more common among the drugs associated with higher reporting frequency in the elderly.

CONCLUSION

Age-specific phenotypes and potential drug properties associated with age-specific hepatotoxicity were identified in reported liver events; further analyses are warranted.

Long-term outcomes of stimulant medication in attention-deficit hyperactivity disorder

The rate of prescribing of stimulant medication for the treatment of attention-deficit hyperactivity disorder (ADHD) has been progressively increasing in countries such as the USA and Australia. In the short term, stimulant medication is effective in reducing the symptoms of ADHD and appears well tolerated with relatively minor side effects. In the long term, much of the benefit of stimulant medication disappears after medication is ceased. Studies have demonstrated only marginal improvements in adult outcomes following a period of treatment in childhood. This may be owing to the beneficial effects being masked by the variability of the condition, the developmental changes in symptomatology that happen with maturation and the substantial influence of social and environmental factors. Stimulant medication may give some protection against later substance abuse. Stimulant medication may slightly elevate the blood pressure and possibly increase susceptibility to seizures and to tics and Tourette syndrome. Starting treatment with stimulant medication is usually associated with weight loss and a transient slowing of the height velocity, although it is believed that most children catch up during puberty. No studies were found that listed strokes or heart attacks as potential or actual complications, although one individual from a group of normal controls died suddenly of cardiac arrest in adolescence. It would appear that the medical complications associated with amphetamine addiction are not relevant to the therapeutic use of stimulant medication in the treatment of ADHD, although there is limited information on extended periods of treatment lasting 10 years or more.

Which psychotropic medications induce hepatotoxicity?

OBJECTIVE

Safe prescribing practices to minimize pharmaceutically induced liver damage or worsening of preexisting conditions require knowledge about medicines with hepatotoxic potential. This paper reviews psychotropic medications and their effects on the liver.

METHODS

A MEDLINE search was performed utilizing the phrase "drug-induced liver injury" with various categories of psychiatric drugs. Only articles written in English were utilized.

RESULTS

Hepatotoxicity can be acute or chronic in nature. Medication discontinuation is necessary in acute forms, while close monitoring is required in milder forms of medication-induced chronic liver damage. Nefazodone, pemoline and/or tacrine are the highest offenders. Carbamazepine and valproate products (e.g., divalproex) can lead to this adverse event and should be avoided in patients with liver disease, persons with alcohol misuse or those consuming high doses of acetaminophen.

CONCLUSION

Knowing the risk levels associated with various medicines is important; prescribing multiple drugs with hepatotoxic effects should be avoided. One should educate patients about early warning signs of liver injury. Always provide clinical and laboratory monitoring before and during the use of hepatotoxic drugs. Clinical features and laboratory results govern medication prescribing with ongoing risk-to-benefit ratio assessment during pharmacotherapy.

Eosinophilic hepatitis in an adolescent during lisdexamfetamine dimesylate treatment for ADHD

We describe here the case of an adolescent who developed eosinophilic hepatitis during treatment for attention-deficit/hyperactivity disorder with lisdexamfetamine dimesylate (Vyvanse [Shire US Inc, Wayne, PA]). A 14-year-old boy presented to his primary care provider with abdominal pain and worsening jaundice. A diagnosis of hepatitis was made with biochemical markers, but evaluation failed to provide an etiology. Worsening hepatitis prompted hospitalization and initiation of steroids for presumed autoimmune hepatitis. A subsequent liver biopsy showed evidence of eosinophilic hepatitis. Known causes of eosinophilic hepatitis were ruled out, and a presumptive diagnosis of reaction to lisdexamfetamine dimesylate was made. Discontinuation of the medication led to resolution of the hepatitis and normalization of the liver biopsy. To our knowledge, this is the first report of hepatic injury attributed to lisdexamfetamine dimesylate.

Effectiveness of risk management plans: a case study of pemoline using pharmacy claims data

PURPOSE

To assess the effectiveness of a pharmaceutical risk management plan using pemoline as a case study and pharmacy claims as the data source.

METHODS

Prescription claims from a continuously enrolled US population (September 1, 2000-September 30, 2002) from Caremark, a pharmacy benefit manager, were evaluated for patients with one or more pemoline claims. Patients were categorized using pemoline as second-line or first-line therapy depending on presence or absence of other central nervous system (CNS) stimulants prescriptions 90 days prior to the first pemoline claim. Logistic regression was performed to compare second-line and first-line usage with regard to patient age, gender and prescribing physician specialty and region of practice.

RESULTS

Of 1,279,296 prescription claims for CNS stimulants, 17,256 (1.3%) were for pemoline. Nine hundred thirteen patients received pemoline and had 90 days or more prior enrollment. Overall, 10% of patients receiving pemoline received it as second-line therapy (95%CI: 8-12%). After adjusting for age, gender, specialty, and region, the odds of receiving pemoline as second-line therapy were significantly greater in pediatrics relative to adults (OR = 2.82, 95%CI: 1.58-5.03), and among those whose prescribers were psychiatrists versus primary care physicians (OR = 2.48, 95%CI: 1.37-4.50). Children treated by a psychiatrist had the greatest likelihood for use as second-line therapy (36%, 95%CI: 19-56%).

CONCLUSIONS

Among patients who received pemoline, concordance with second-line therapy recommendations was low, even among the primary target audience of children. These results in a large geographically diverse patient population are consistent with an earlier regional study.

Idiosyncratic toxicity: a convergence of risk factors

The therapeutic margin for any drug is based on both toxicity and efficacy. Generally, toxicity is dose-dependent and is driven either by the therapeutic target or by an untoward target. However, idiosyncratic toxicities are usually not observed until a drug has been on the market and has gained broad exposure. Except in the case of pharmacokinetic interactions, these toxicities are not driven solely by drug exposure but rather depend on several drug- and patient-related risk factors. Drug-related risk factors include metabolism, bioactivation and covalent binding, and the inhibition of key cell functions. Patient-related risk factors include underlying disease, age, gender, comedications, nutritional status, activation of the innate immune system, physical activity, and genetic predispositions. Idiosyncratic toxicity can occur when a convergence of risk factors, including drug exposure, tips the risk-benefit balance away from benefit and toward risk.

Evidence-based guidelines for management of attention-deficit/hyperactivity disorder in adolescents in transition to adult services and in adults: recommendations from the British Association for Psychopharmacology

Attention-deficit/hyperactivity disorder (ADHD) is an established diagnosis in children, associated with a large body of evidence on the benefits of treatment. Adolescents with ADHD are now leaving children's services often with no readily identifiable adult service to support them, which presents problems as local pharmacy regulations often preclude the prescription of stimulant drugs by general practitioners (GPs). In addition, adults with ADHD symptoms are now starting to present to primary care and psychiatry services requesting assessment and treatment. For these reasons, the British Association for Psychopharmacology (BAP) thought it timely to hold a consensus conference to review the body of evidence on childhood ADHD and the growing literature on ADHD in older age groups. Much of this initial guidance on managing ADHD in adolescents in transition and in adults is based on expert opinion derived from childhood evidence. We hope that, by the time these guidelines are updated, much evidence will be available to address the many directions for future research that are detailed here.

Pharmacotherapy for excessive daytime sleepiness

Excessive daytime sleepiness (EDS) has recognized detrimental consequences such as road traffic accidents, impaired psychological functioning and reduced work performance. EDS can result from multiple causes such as sleep deprivation, sleep fragmentation, neurological, psychiatric and circadian rhythm disorders. Treating the underlying cause of EDS remains the mainstay of therapy but in those who continue to be excessively sleepy, further treatment may be warranted. Traditionally, the amphetamine derivatives, methylphenidate and pemoline (collectively sympathomimetic) psychostimulants were the commonest form of therapy for EDS, particularly in conditions such as narcolepsy. More recently, the advent of modafinil has broadened the range of therapeutic options. Modafinil has a safer side-effect profile and as a result, interest in this drug for the management of EDS in other disorders, as well as narcolepsy, has increased considerably. There is a growing school of thought that modafinil may have a role to play in other indications such as obstructive sleep apnea/hypopnea syndrome already treated by nasal continuous positive airway pressure but persisting EDS, shift work sleep disorders, neurological causes of sleepiness, and healthy adults performing sustained operations, particularly those in the military. However, until adequately powered randomised-controlled trials confirm long-term efficacy and safety, the recommendation of wakefulness promoters in healthy adults cannot be justified.

Adolescents with attention-deficit/hyperactivity disorder: an overview of empirically based treatments

The author first presents an overview of attention-deficit/hyperactivity disorder (ADHD) as it presents in adolescents. He reviews what is known about the predominantly inattentive subtype in adolescents, the persistence of symptoms into this developmental phase, and comorbid disorders in adolescent patients with ADHD. The author then reviews treatments for adolescents with ADHD for which there is some empirical support in the scientific literature. He first discusses common assumptions concerning the treatment of ADHD and evidence for or against these assumptions. Information on therapies that have been shown to be ineffective or the benefit of which is unproven are then described. These include cognitive-behavioral therapy and social skills training. The author then presents an overview of what is known about the medication treatment of ADHD and discusses how this information is applicable to adolescents with the disorder. Four main classes of drugs are discussed: stimulants, noradrenergic reuptake inhibitors, tricyclic antidepressants, and antihypertensive agents. The author then reviews the use of several psychosocial interventions, including contingency management strategies, parent training in behavior management methods, and teacher training in classroom management, and discusses how these strategies can best be used for adolescents with ADHD. The author then discusses the use of combined treatment with psychosocial interventions and medication. Finally, information on the use of physical exercise as therapy for adolescents with ADHD is discussed.

Immune-mediated drug-induced liver disease

Drug-induced immune-mediated hepatic injury is an adverse immune response against the liver that results in a disease with hepatitic, cholestatic, or mixed clinical features. Drugs such as halothane, tienilic acid, dihydralazine, and anticonvulsants trigger a hepatitic reaction, and drugs such as chlorpromazine, erythromycins, amoxicillin-calvulanic acid, sulfonamides and sulindac trigger a cholestatic or mixed reaction. Unstable metabolites derived from the metabolism of the drug may bind to cellular proteins or macromolecules, leading to a direct toxic effect on hepatocytes. Protein adducts formed in the metabolism of the drug may be recognized by the immune system as neoantigens. Immunocyte activation may then generate autoantibodies and cell-mediated immune responses, which in turn damage the hepatocytes. Cytochromes 450 are the major oxidative catalysts in drug metabolism, and they can form a neoantigen by covalently binding with the drug metabolite that they produce. Autoantibodies that develop are selectively directed against the particular cytochrome isoenzyme that metabolized the parent drug. The hapten hypothesis proposes that the drug metabolite can act as a hapten and can modify the self of the individual by covalently binding to proteins. The danger hypothesis proposes that the immune system only responds to a foreign antigen if the antigen is associated with a danger signal, such as cell stress or cell death. Most clinically overt adverse hepatic events associated with drugs are unpredictable, and they have intermediate (1 to 8 weeks) or long latency (up to 12 months) periods characteristic of hypersensitivity reactions. Immune-mediated drug-induced liver disease nearly always disappears or becomes quiescent when the drug is removed. Methyldopa, minocycline, and nitrofurantoin can produce a chronic hepatitis resembling AIH if the drug is continued.

A study of compliance with FDA recommendations for pemoline (Cylert)

OBJECTIVE

To assess compliance with product labeling recommendations to use pemoline as second-line therapy for attention-deficit/hyperactivity disorder (ADHD) and to obtain baseline and biweekly liver enzyme tests.

METHOD

Retrospective cohort study using administrative claims data to identify first-line therapies and liver enzyme tests among pemoline users between January 1, 1998, and March 31, 2000. Prescriptions for first-line therapy were searched for 90 days prior to the first pemoline claim. Liver enzyme testing (baseline and follow-up) was compared between two groups (the prerecommendation cohort October 1,1998, to March 31, 1999, and the postrecommendation cohort October 1,1999, to March 31,2000).

RESULTS

1,308 patients received at least one pemoline prescription during the study period; 76% of patients < or = 20 years were male. ADHD was the claims-identified indication for 688 patients (52%). Despite the labeling recommendation for use as second-line therapy, only 237 ADHD patients (34%) received a first-line therapy prior to pemoline. Only 12% and 11% of the pre- and post-cohort patients, respectively, received baseline liver enzyme tests; 9% in the pre- and 12% in the post-cohort received at least one liver enzyme follow-up test.

CONCLUSIONS

Compliance with product labeling was low for both recommendations. Understanding the reasons for this finding could help improve risk management strategies.

Pemoline ingestion in children: a report of five cases and review of the literature

The authors describe five pediatric cases of excessive pemoline ingestion. Based on their experience compared with previously reported cases in the literature, they describe the clinical presentation and rational treatment recommendations for acute pemoline ingestion. Overall, patients experienced a relatively benign clinical course following pemoline ingestion. Symptoms of pemoline ingestion appear to be primarily an accentuation of the drug's pharmacological effects on the central nervous and cardiovascular systems with sinus tachycardia, hypertension, hyperactivity, choreoathetoid movements, and hallucinations being most commonly observed. These findings are consistent with previously reported cases. Possible rhabdomyolysis manifested by evaluation of serum CPK was also observed in 3 of 4 patients in whom this laboratory parameter was measured and appears to be a common finding in acute pemoline poisoning. After acute ingestion, symptoms occurred within 6 hours, lasting up to 48 hours in all patients. Gastric lavage and/or activated charcoal would be effective decontamination measures, whereas ipecac-induced emesis should be avoided after massive ingestion due to the possibility of seizures. Aggressive use of a benzodiazepine appears a reasonable first choice to treat associated involuntary movements, tremor, hyperactivity, irritability, and agitation. Phenothiazines or butyrophenones may also be used especially for serious life-threatening symptoms, including hypertensive crisis and severe hyperthermia, although these serious complications of stimulant overdose have not been reported after pemoline ingestion. If a patient should experience pemoline-induced hypertensive crisis, individual dose titration of labetalol or sodium nitroprusside would appear reasonable pharmacologic approaches for rapid stabilization of blood pressure.

[Evaluated treatment approaches in child and adolescent psychiatry I]

OBJECTIVES

The principle of evidence-based medicine is to integrate data concerning the efficacy of interventions into clinical practice. This article assesses the level of evaluation of psychosocial, psychopharmacological and combined interventions for mental disorders in childhood and adolescence (autistic disorders, hyperkinetic disorders, conduct disorders, tic disorders, enuresis, and encopresis).

METHODS

Three different levels of evaluation were defined for both psychosocial and psychopharmacological interventions: A (> or = 2 randomized controlled studies), B (1 randomized controlled study), and C (open studies and case studies). The level of evaluation was judged on the basis of original papers found in a comprehensive literature search.

RESULTS

For most disorders presented in this article there are several A-level treatments. The efficacy of both psychosocial and psychopharmacological interventions that target specific problem behaviors or symptoms, respectively, has been repeatedly demonstrated with regard to autistic disorders. Many studies have evaluated treatment approaches for hyperkinetic disorders and conduct disorders. With regard to the treatment of tic disorders in children and adolescents, far more studies evaluated the efficacy of pharmacotherapy than of psychotherapy.

CONCLUSIONS

Further research should compare the efficacy of different treatment approaches, examine specific and differential treatment effects and investigate combined treatment approaches.

Pemoline hepatotoxicity and postmarketing surveillance

OBJECTIVE

To review the numerous reports of hepatotoxic adverse drug reactions (ADRs) ascribed to pemoline that were sent to the U.S. Food and Drug Administration (FDA) between 1975 and 1996 and to describe the medical community's lack of awareness of these reports.

METHOD

All ADR reports from 1975 through 1996 wherein pemoline was the suspect agent were obtained from the FDA MedWatch Internet site, and some details of nine pemoline-related deaths in youths were obtained directly from the FDA. The published literature on this subject was fully reviewed.

RESULTS

(1) In premarketing clinical trials with pemoline in the early 1970s, hepatic abnormalities were noted in enzyme levels (1%-3% of youths receiving maintenance treatment), during rechallenges (6 of 6), and in biopsies (2 of 2). (2) Between 1975 and 1989, 12 cases of jaundice and 6 deaths in youths ascribed to pemoline hepatotoxicity were reported to the FDA. (3) The first medical literature report of a serious ADR ascribed to pemoline was in a 1989 letter to the editor. (4) Physicians generally only became aware of serious pemoline hepatotoxicity in December 1996. (5) Pemoline use increased until 1997.

CONCLUSION

Limitations in postmarketing surveillance and public reporting in the United States, particularly in the 1980s, largely accounted for delays in an appropriate response to pemoline hepatotoxicity.

Drug-induced liver disease

The incidence of drug-induced liver disease appears to be increasing, reflecting the increasing number of new agents that have been introduced into clinical use over the past several decades. Among the topics covered, the author discusses incidence, diagnosis, risk factors, clinical presentations, hepatitis, and vascular injury. The author also reviews the hepatic injury seen with commonly prescribed drugs, emphasizing newer developments in the field and recent publications and reports.

National Institutes of Health Consensus Development Conference Statement: diagnosis and treatment of attention-deficit/hyperactivity disorder (ADHD)

Attention-deficit/hyperactivity disorder (ADHD) is a commonly diagnosed behavioral disorder of childhood that represents a costly major public health problem. Despite progress, ADHD and its treatment have remained controversial, especially the use of psychostimulants for both short- and long-term treatment. Although an independent diagnostic test for ADHD does not exist, there is evidence supporting the validity of the disorder. Studies (primarily short-term, approximately 3 months), including randomized clinical trials, have established the efficacy of stimulants and psychosocial treatments for alleviating the symptoms of ADHD and associated aggressiveness and have indicated that stimulants are more effective than psychosocial therapies in treating these symptoms. Because of the lack of consistent improvement beyond the core symptoms and the paucity of long-term studies (beyond 14 months), there is a need for longer-term studies with drugs and behavioral modalities and their combination. Although trials are under way, conclusive recommendations concerning treatment for the long term cannot be made at present. There are wide variations in the use of psychostimulants across communities and physicians, suggesting no consensus regarding which ADHD patients should be treated with psychostimulants, and thus the need for improved assessment, treatment, and follow-up. Furthermore, the lack of insurance coverage, preventing the appropriate diagnosis and treatment of ADHD, and the lack of integration with educational services are substantial barriers and represent considerable long-term costs for society. Finally, after years of clinical research and experience with ADHD, knowledge about the cause or causes of ADHD remain largely speculative. Consequently, there are no documented strategies for the prevention of ADHD.

Attention-deficit hyperactivity disorder on the frontlines: management in the primary care office

Attention-deficit hyperactivity disorder (ADHD) is a common, disabling pediatric psychiatric disorder. Diagnosis of this disorder requires systematic data collection from multiple sources. The preferred therapy for ADHD is a combination of behavioral modification, educational assistance, and stimulant medications.

Drug-induced liver disease

The past year has seen several additions to the list of drugs that cause hepatic injury. Many of these agents produce fulminant hepatic necrosis and, in some cases, were withdrawn from the market (eg, bromfenac). Other drugs had warnings placed in their labeling along with stringent monitoring guidelines to alert physicians and patients alike to the potential for severe hepatic injury (eg, troglitazone, tolcapone). New reports of hepatoxicity continued to appear for many older agents, in some cases expanding the hepatotoxic spectrum for the drugs. Vanishing bile duct syndrome has drawn increasing attention and is now associated with more than 30 drugs. Ibuprofen is among those drugs newly described as causing this syndrome. Hepatitis C virus infection was reported as a possible risk factor for ibuprofen hepatotoxicity, raising the issue of safe use of nonprescription as well as prescription drugs in patients with underlying liver disease. Reports have appeared about acetaminophen-induced hepatotoxicity in several dozen children from unintentional overdoses, in addition to cases of therapeutic misadventure in adults.