Pediatric patients with undetectable anticonvulsant blood levels: comparison with compliant patients.

Undetectable anticonvulsant blood levels indicate sustained noncompliance (several consecutive doses missed). We compared 91 consecutive outpatients with epilepsy and undetectable anticonvulsant blood levels to 100 patients seen during the same time period, verified as compliant by acceptable serum levels. We hypothesized that pay status, application for Supplemental Security Income, patient age, history of missed appointments, and functional status would differ between compliant and noncompliant patients. We were surprised to find large differences between clinic and insurance patients and between Caucasian and non-Caucasian patients. The 100 compliant patients included 44 Caucasian and 56 non-Caucasian patients, whereas only 9 of 91 noncompliant patients were Caucasian, and only 9 had insurance, compared to 32 compliant patients. Applications for Supplemental Security Income and history of missed appointments were significantly associated with noncompliance, but patient age, seizure type, and seizure control were not. Uninsured Caucasians were more often compliant than non-Caucasians were. Many noncompliant patients had mild epilepsy, which was reportedly doing well. Race and pay status were closely correlated. Several noncompliant females became pregnant, whereas no compliant patients did. Compliant patients were much more likely to be accompanied by a parent or caretaker on clinic visits than noncompliant patients. Noncompliant patients had at least one acceptable subsequent serum level, although 2 patients with intractable epilepsy had undetectable serum levels on three or more occasions. Noncompliance may respond to discussion and advice. We reviewed 124 episodes of undetectable drug levels in the 91 noncompliant patients. Eighteen of these resulted in hospitalization, but in 25 cases, we were told that there had been no seizures since the preceding visit. Many noncompliant patients have infrequent seizures, even if they take little or no medication. Socioeconomic status influences health, life expectancy, and educational success, but it has been claimed to be irrelevant to compliance and adherence issues in epilepsy. Our data and the experience of other centers with childhood diabetes suggest that socioeconomic, racial, and family factors influence compliance or adherence to treatment for many chronic conditions. Educational efforts and support for parents at the start of anticonvulsant treatment may improve compliance. Uninsured patients missed more appointments and were much more likely to be noncompliant than insured patients. Attention to the special problems of Medicaid and minority children is needed.

Anticonvulsant blood levels: historical review with a pediatric focus.

Epilepsy is heterogeneous and its treatment is often complicated by variable drug responses. Buchtal et al reported a close correlation between serum phenytoin levels, electroencephalographic findings, and clinical status in 1960. They suggested that physicians adjust dosage to attain a "therapeutic level." The concept was enthusiastically received. "Therapeutic serum levels" were proposed for most anticonvulsant drugs, and by 1975, most authorities believed that pharmacokinetic factors explained individual differences in drug response. However, Froscher found that measuring levels did not improve patient outcome. More recently, Schumacher's double-blind study found no correlation between phenytoin levels and seizure control or adverse effects. Pharmacodynamic variables (differences in drug responsiveness) are more important than pharmacokinetic factors for many drugs, especially receptor-active drugs. Pharmacokinetic variables were studied first, and led to a simplistic model. They are less significant than pharmacodynamic factors in the case of warfarin anticoagulation. Anticonvulsant levels can reveal noncompliance and pharmacokinetic differences. They say nothing about pharmacodynamics. Reports of "subtherapeutic levels" imply a need to increase dosage, but this is not supported by outcome data. We still lack evidence that specific drug levels are a valid intermediate target 40 years after Buchtal's paper. Responses to some anticonvulsants could depend primarily on pharmacokinetic factors, while pharmacodynamic factors could be supreme for others.

Quality of life assessment by community pharmacists: an exploratory study.

Implicit in the evolving role of pharmacy is that its practitioners embrace the concept of quality of life (QoL). In recent years there has been an increased interest in incorporating health-related quality of life (HRQoL) measures into clinical practice, primarily focusing on the physician as the user of this information. Pharmacists may be able to use these instruments in their practices to provide better pharmaceutical care. To explore the feasibility of such an undertaking, questionnaires were mailed to a national sample of community pharmacies. In addition to the questionnaire, the respondents were provided with examples of two instruments: the Duke Health Profile and the QOLIE-10. A definition of HRQoL was provided to the respondents. After two mailings and a reminder postcard, a usable response rate of 27.2% was achieved. The results revealed that over 80% of the respondents currently discuss HRQoL issues with their patients. In addition, 66% reported that they attempt to assess the HRQoL of their patients, albeit usually on a subjective, informal basis. After viewing examples of HRQoL instruments, over three-quarters of the respondents reported a willingness to use HRQoL assessment tools in their practices. However, only 53.7% of the respondents were familiar with the concept of HRQoL. Less than 5% reported familiarity with formal instruments. The self-reported knowledge of pharmacists concerning HRQoL was low and the respondents recognized a significant gap between their current knowledge and the level of knowledge needed to assess the HRQoL of their patients formally. The results suggest a possible role for the pharmacist in HRQoL assessment. However, the use of HRQoL instruments in community pharmacies will require further training and education on the part of pharmacists concerning the concept of HRQoL, the issues involved in its measurement and how they can use HRQoL information in their practices. In addition, a number of unanswered questions must be addressed through the research process in order for HRQoL questionnaires to become clinical tools in the practice of pharmacy.

Muscle rigidity due to fentanyl infusion in the pediatric patient.

Two cases of fentanyl-induced muscle rigidity are presented. Significant features of these cases include the unusual pattern of rigidity and the use of fentanyl doses lower than those usually associated with muscle rigidity.

The safety, tolerability, and pharmacokinetics of fosphenytoin after intramuscular and intravenous administration in neurosurgery patients.

STUDY OBJECTIVE: To evaluate the safety, tolerability, and pharmacokinetic profile of fosphenytoin, a water-soluble phenytoin prodrug, after intramuscular and intravenous administration. DESIGN: Open-label study of intramuscular administration, and double-blind, randomized study of intravenous administration. SETTING: Six and ten hospitals throughout the United States for the intramuscular and intravenous multicenter studies, respectively. PATIENTS: Neurosurgical patients who required anticonvulsant prophylaxis or treatment. INTERVENTIONS: In the intramuscular study, 118 patients received loading doses ranging from 480-1500 mg phenytoin equivalents (PE) and daily maintenance doses ranging from 130-1250 mg PE for 3-14 days. In the intravenous study, 88 patients received fosphenytoin and 28 received phenytoin sodium for 3-14 days. Mean +/- SD loading doses and maintenance doses of intravenous fosphenytoin and phenytoin were 1082 +/- 299 mg PE and 411 +/- 221 mg PE, and 1082 +/- 299 mg and 422 +/- 197 mg, respectively. Trough phenytoin concentrations were measured daily in all patients. MEASUREMENTS AND MAIN RESULTS: Intramuscular fosphenytoin was safe and well tolerated, with no irritation found for 99% of all injection site evaluations. Adverse events associated with the drug occurred in 9% of patients, commonly those typical of the parent drug. For intravenous treatment, the frequency of mild irritation at the infusion site was significantly lower in the fosphenytoin group (6%) than in the phenytoin group (25%, p < 0.05). Reductions in infusion rates were required in 17% and 36% of fosphenytoin and phenytoin recipients, respectively. No significant difference was observed relative to adverse events or seizure frequency between the groups. Trough plasma phenytoin concentrations were approximately 10 micrograms/ml or greater in patients receiving at least 3 days of intramuscular and intravenous fosphenytoin. Trough phenytoin concentrations were similar between patients receiving intravenous phenytoin and fosphenytoin on all study days. CONCLUSION: Fosphenytoin can be administered intramuscularly and intravenously in neurosurgical patients to achieve and maintain therapeutic phenytoin concentrations for up to 14 days. Both routes are safe and well tolerated. Intravenous fosphenytoin is significantly better tolerated than intravenous phenytoin sodium in this patient subset.

Drug therapy for epilepsy.

Epilepsy, a chronic brain disorder characterized by recurrent seizures, affects 1 to 3 percent of the U.S. population. In addition to six drugs classically used either alone or in combination to control epilepsy, three new agents have recently become available. The choice of therapy for each patient must be individualized, based on an accurate determination of the type of epilepsy, an understanding of drug pharmacokinetics, interactions and side-effect profiles, and issues related to patient acceptability and compliance. Approximately 70 percent of patients currently achieve good control of epilepsy, and it is hoped that new agents and improved therapeutic management can substantially increase this percentage.

Intraosseous administration of antibiotics: same-dose comparison with intravenous administration in the weanling pig.

STUDY OBJECTIVES: To assess the reliability of the intraosseous route of administration for delivery of a loading dose of broad-spectrum antibiotics in a pediatric animal model. DESIGN: Serum levels achieved within 90 minutes of equivalent intraosseous (IO) and IV bolus dosing of ceftriaxone, cefotaxime, and a combination of ampicillin and gentamicin were compared in the weanling pig. SUBJECTS: Twelve female weanling pigs were studied in the Animal Facilities Laboratory at the University of Mississippi Medical Center. INTERVENTIONS: Through a proximal tibial IO catheter, each anesthetized animal received one of the following: 50 mg/kg ceftriaxone, 50 mg/kg cefotaxime, or 300 mg/kg ampicillin followed immediately by 2.5 mg/kg gentamicin. Venous blood was obtained for antibiotic assay at 15, 30, 45, 60, and 90 minutes after IO injection. The animals were allowed to recover, and, after a one-week washout period, each received the same antibiotic and dose as before through a peripheral IV. Levels were assayed at the same intervals and IO versus IV were compared. MEASUREMENTS AND MAIN RESULTS: Comparable serum levels of all four antibiotics were achieved by the two routes. Gentamicin levels were statistically indistinguishable IO versus IV at all assay intervals. Ampicillin and cefotaxime levels achieved by the two routes were equivalent within one hour of dosing. Serum levels of ceftriaxone after IO administration paralleled those after IV dosing but remained significantly lower at all time intervals. CONCLUSIONS: In the weanling pig model, the IO route was used to deliver serum levels of broad-spectrum antibiotics comparable to those attained after IV administration. The data support the use of standard parenteral doses for IO administration. To overcome potential avid protein binding of ceftriaxone in the bone marrow, we recommend using ceftriaxone at its highest recommended IO loading dose. Consistent with many other medications that have been similarly tested, these data indicate that initial or empiric antibiotic coverage in hypodynamic and shock states in infants and young children need not await the establishment of traditional IV access.

Toxicity with dextromethorphan-containing preparations: a literature review and report of two additional cases.

Dextromethorphan-containing cold/cough preparations are frequently prescribed and bought over the counter for use in children. Although generally considered safe, dextromethorphan has been shown to cause CNS side effects, including hyperexcitability, increased muscle tone, and ataxia. Two deaths have been reported with intentional dextromethorphan overdose. A literature review, brief review of pharmacology, and report of two cases of adverse reactions to dextromethorphan-containing preparations are presented.

Metabolism and disposition of indomethacin in preterm infants.

38 preterm infants with symptomatic patent ductus arteriosus received indomethacin intravenously. Plasma samples were collected at 2, 4, 6 or 8 and 12 h after each of 3 doses. Indomethacin, demethylindomethacin and p-chlorobenzoic acid were determined in plasma and urine along with acid-labile metabolites using HPLC. Fifty-eight percent of the infants demethylated indomethacin; half of the unchanged and demethylated drug was found as conjugates in urine; 14% deacylated the drug. Shorter elimination half-life, smaller area under the plasma concentration-time curves and increased plasma clearance were associated with demethylation. Postnatal age greater than 2 weeks correlated with both demethylation and failure of indomethacin to effect ductal closure.

Elevated serum iron levels following administration of cisplatinum.

An increase in serum iron levels and a decrease in serum unsaturated iron binding capacity (uIBC) were noted following the administration of cisplatinum to 9 children with malignancies. The mean serum iron concentration increased from a pretreatment level of 75.7 +/- 30.5 micrograms/ml to a posttreatment level of 162.1 +/- 65.3 micrograms/ml with the first cisplatinum treatment course (p less than 0.004). The uIBC concomitantly decreased from 181.9 +/- 33.7 micrograms/ml to 86.4 +/- 44.6 micrograms/ml (p less than 0.0005). A cumulative effect was noted following subsequent courses. The levels returned to baseline values within 2-4 months following cessation of therapy in 6 children in whom follow-up data were available. It is possible that this reversal of the iron/uIBC ratio is the result of cisplatinum competition for iron binding sites to proteins.