An update on sodium valproate

Zinc as a therapy in a rat model of autism prenatally induced by valproic acid

Autism is characterized by numerous behavioral impairments, such as in communication, socialization and cognition. Recent studies have suggested that valproic acid (VPA), an anti-epileptic drug with teratogenic activity, is related to autism. In rodents, VPA exposure during pregnancy induces autistic-like effects. Exposure to VPA may alter zinc metabolism resulting in a transient deficiency of zinc. Therefore, we selected zinc as a prenatal treatment to prevent VPA-induced impairments in a rat model of autism. Wistar female rats received either saline solution or VPA (400 mg/kg, i.p) on gestational day (GD) 12.5. To test the zinc supplementation effect, after 1 h of treatment with saline or VPA, a dose of zinc (2 mg/kg, s.c.) was injected. The offspring were tested for abnormal communication behaviors with an ultrasound vocalization task on postnatal day (PND) 11, repetitive behaviors and cognitive ability with a T-maze task on PND 29, and social interaction with a play behavior task on PND 30. Tyrosine hydroxylase protein (TH) expression was evaluated in the striatum. Prenatal VPA decreased ultrasonic vocalization, induced repetitive/restricted behaviors and cognitive inflexibility, impaired socialization, and reduced striatal TH levels compared with control group. Zinc treatment reduced VPA-induced autistic-like behaviors. However, we found no evidence of an effect of zinc on the VPA-induced reduction in TH expression. The persistence of low TH expression in the VPA-Zn group suggests that Zn-induced behavioral improvement in autistic rats may not depend on TH activity.

In vivo inhibition of acylpeptide hydrolase by carbapenem antibiotics causes the decrease of plasma concentration of valproic acid in dogs

1. Our previous in vitro studies suggest that inhibition of the acylpeptide hydrolase (APEH) activity as valproic acid glucuronide (VPA-G) hydrolase by carbapenems in human liver cytosol is a key process for clinical drug-drug interaction (DDI) of valproic acid (VPA) with carbapenems. Here, we investigated whether in vivo DDI of VPA with meropenem (MEPM) was caused via inhibition of APEH in dogs. 2. More rapid decrease of plasma VPA levels and increased urinary excretion of VPA-G were observed after co-administration with MEPM compared with those after without co-administration, whereas the plasma level and bile excretion of VPA-G showed no change. 3. Dog VPA-G hydrolase activity, inhibited by carbapenems, was mainly located in cytosol from both the liver and kidney. APEH-immunodepleted cytosols lacked VPA-G hydrolase activity. Hepatic and renal APEH activity was negligible even at 24 h after dosing of MEPM to a dog. 4. In conclusion, DDI of VPA with carbapenems in dogs is caused by long-lasting inhibition of APEH-mediated VPA-G hydrolysis by carbapenems, which could explain the delayed recovery of plasma VPA levels to the therapeutic window even after discontinuation of carbapenems in humans.

Animal models of autism: an epigenetic and environmental viewpoint

Autism is a neurodevelopmental disorder of social behavior, which is more common in males than in females. The causes of autism are unknown; there is evidence for a substantial genetic component, but it is likely that a combination of genetic, environmental and epigenetic factors contribute to its complex pathogenesis. Rodent models that mimic the behavioral deficits of autism can be useful tools for dissecting both the etiology and molecular mechanisms. This review discusses animal models of autism generated by prenatal or neonatal environmental challenges, including virus infection and exposure to valproic acid (VPA) or stress. Studies of viral infection models suggest that interleukin-6 can influence fetal development and programming. Prenatal exposure to the histone deacetylase inhibitor VPA has been linked to autism in children, and male VPA-exposed rats exhibit a spectrum of autistic-like behaviors. The experience of prenatal stress produces male-specific behavioral abnormalities in rats. These effects may be mediated by epigenetic modifications such as DNA methylation and histone acetylation resulting in alterations to the transcriptome.

[Therapeutic drug monitoring of valproate]

Valproic acid is an anticonvulsant drug available in France since 1967. It is a broad spectrum molecule indicated in various forms of epilepsy of the adult and the child, but it is also prescribed in the treatment of different other pathologies of nervous system. The divalproate sodium is indicated in the treatment of bipolar disorders. The valproic acid is marketed under various pharmaceutical forms, with different corresponding tmax values. But, whatever the administered preparation, the circulating active molecule is the ion valproate. Elimination half-life is from 11 to 20 h. Metabolization of valproate is important and represents its main route of elimination. Valpromide is comparable to a prodrug which metabolizes in valproate. The inter and intraindividual variability of the plasma concentrations are important. Several studies show a concentration-effect relationship, but two interventional trials ended in the lack of interest of the Therapeutic Drug Monitoring (TDM), although it is of current practice. However, numerous drug interactions may modify the plasma concentrations of valproate. The therapeutic range is from 50 to 100 mg/L (346-693 micromol/L). The level of proof of the interest of the TDM for this molecule was estimated in: recommended.

A randomized trial of propranolol versus sodium valproate for the prophylaxis of migraine in pediatric patients

BACKGROUND

Migraine is the most common of the paroxysmal disorders to affect the brain in the pediatric population. Both propranolol and sodium valproate (valproic acid) have been advocated as prophylactic agents for childhood migraine.

OBJECTIVE

To compare the efficacy and tolerability of propranolol and sodium valproate in the prevention of migraine in the pediatric population.

METHODS

Sixty-three children (aged 5-15 years) with migraine without aura, as defined by the 2004 International Headache Society (IHS) criteria, were included in this prospective, double-blind clinical trial and were randomly assigned to two groups. Group A (n = 32 patients) received propranolol 3 mg/kg/day and group B (n = 31 patients) received sodium valproate 30 mg/kg/day, with at least 6 months of follow up. The propranolol dosage was adjusted to 2 mg/kg/day and the sodium valproate dosage to 15 mg/kg/day, after the first follow-up visit. Participants were evaluated by using a detailed questionnaire that asked about the features of headaches and general health characteristics. The study endpoints were successful treatment for a 4- to 6-month period; 3 months of a persistent unsuccessful or incomplete response to treatment; intolerable side effects; and/or patient non-adherence. All data were analyzed longitudinally by comparing baseline data with data from each follow-up.

RESULTS

A total of 60 patients completed the full headache prophylaxis period. The baseline headache frequency was reduced by more than 50% in 83% of propranolol recipients and in 63% of sodium valproate recipients (statistically not significant); the overall reduction of baseline headache frequency per month was better in group A (p = 0.044). The mean headache frequency per month was reduced from 13.86 +/- 2.11 to 4.23 +/- 3.24 in group A, and from 13.23 +/- 2.43 to 5.83 +/- 4.04 in group B; the difference between the two groups was statistically significant (p < 0.01). The mean headache duration per week was decreased from 9.9 +/- 7.4 hours to 3.2 +/- 5.9 hours in group A, and from 9.1 +/- 6.9 hours to 3.7 +/- 5.0 hours in group B; although there was no statistically significant difference between propranolol and sodium valproate, headache duration was markedly improved with each drug (p < 0.002). Reduction of headache severity by at least one grade was seen in 64% of patients in group A and in 56% in group B, and complete cessation of headache attacks occurred in 14% of patients in group A and 10% in group B (not significant). Minor side effects appeared to be fairly well tolerated by patients in both groups, with no significant difference in side effects between the two groups.

CONCLUSION

This prospective study supports the efficacy of propranolol and sodium valproate as prophylaxis for pediatric migraine without aura, based on IHS criteria. There were no significant differences between these two drugs in all evaluated parameters except for the mean headache frequency per month, which was lower with propranolol than with sodium valproate.

Identification of valproic acid glucuronide hydrolase as a key enzyme for the interaction of valproic acid with carbapenem antibiotics

Plasma levels of valproic acid (VPA) are decreased by concomitant use with carbapenem antibiotics, such as panipenem (PAPM). One of the plausible mechanisms of this interaction is the inhibition of VPA glucuronide (VPA-G) hydrolysis by carbapenems in the liver. To elucidate this interaction mechanism, we purified VPA-G hydrolase from human liver cytosol, in which the hydrolytic activity was mainly located. After chromatographic purification, the VPA-G hydrolase was identified as acylpeptide hydrolase (APEH). APEH-depleted cytosol, prepared by an immunodepletion method, completely lacked the hydrolytic activity. These results demonstrate that APEH is a single enzyme involved in PAPM-sensitive VPA-G hydrolysis in cytosol. In addition, the hydrolytic activity of recombinant human APEH was inhibited by PAPM and the inhibition profile by typical esterase inhibitors (diisopropyl fluorophosphate, 5,5'-dithiobis(2-nitrobenzoic acid), p-chloromercuribenzoic acid, and d-saccharic acid 1,4-lactone) was similar to that of human liver cytosol. Cytosolic VPA-G hydrolase activity was slightly inhibited by cholinesterase and carboxylesterase inhibitors. beta-Glucuronidase activity remained in APEH-depleted cytosol, whereas VPA-G hydrolase activity was completely abolished. Thus, either cholinesterase, carboxylesterase, or beta-glucuronidase in cytosol would not be involved in VPA-G hydrolysis. Taken together, APEH plays a major role in the PAPM-sensitive VPA-G hydrolysis in the liver. These findings suggest that APEH could be a key enzyme for the drug interaction of VPA with carbapenems via VPA-G hydrolysis.

Effect of concomitant administration of meropenem and valproic acid in an elderly Chinese patient

BACKGROUND

Meropenem is a carbapenem with a broad spectrum of activity against beta-lactamase-producing organisms. Valproic acid is widely used in the treatment of generalized tonic-clonic and partial seizures. Concomitant administration of meropenem and valproic acid reportedly leads to a rapid decline in serum concentrations of valproic acid, which is sometimes associated with seizures.

CASE SUMMARY

This report describes an 85-year-old Chinese male inpatient who twice received concomitant administration of meropenem and valproic acid for the treatment of pneumonia and poststroke epilepsy, respectively. Rapid declines in valproic acid concentrations were observed both times after meropenem administration. No seizures occurred in the first treatment period; however, when the patient suffered pneumonia again 3 months later, the same concomitant therapy was prescribed, and seizures occurred. It is difficult to identify a single etiology of the seizures. Based on a score of 7 on the Naranjo adverse drug reaction probability scale, the seizures were considered to be probably related to the concomitant administration of meropenem and valproic acid.

CONCLUSIONS

Various factors make the effect of concomitant administration of meropenem and valproic acid unpredictable, even in the same patient. Caution should be used when administering meropenem and valproic acid concomitantly, especially in elderly patients with central nervous system disorders, even if the patient has had a successful prior experience with these 2 drugs. If concomitant administration is essential, very close serum concentration monitoring and clinical observation are necessary.

New developments for the pharmacological treatment of alcohol withdrawal syndrome. A focus on non-benzodiazepine GABAergic medications

Alcohol withdrawal syndrome (AWS) can be a life-threatening condition affecting some alcohol-dependent patients who abruptly discontinue or decrease their alcohol consumption. The main objectives of the clinical management of AWS include: to decrease the severity of symptoms, prevent more severe withdrawal clinical manifestations and facilitate entry of the patient into a treatment program in order to attempt to achieve and maintain long-term abstinence from alcohol. At present, benzodiazepines represent the drugs of choice in the treatment of AWS. However, in line with the possible side effects and addictive properties related to benzodiazepine use, there is growing evidence to suggest that non-benzodiazepine GABAergic compounds represent promising medications in the treatment of alcohol-dependent patients. This review focuses on research into non-benzodiazepine GABAergic medications for the treatment of AWS. Among them, carbamazepine, gabapentin and valproic acid are the most studied. The studies on carbamazepine seem to be the most compelling. Preliminary data have also suggested the possible utility of baclofen and topiramate, although further evidence is needed. The promising results in terms of both safety and efficacy are reported. However, we also note the need of more methodologically controlled studies on a greater number of patients, involving more complicated forms of AWS.

Meropenem –valproic acid interaction in patients with cefepime-associated status epilepticus

PURPOSE

Two case reports of rapid decreases in valproic acid levels after initiation of meropenem in patients who developed new-onset seizure activity during treatment with cefepime are presented.

SUMMARY

A 60-year-old Caucasian woman with myelodysplasia was transferred to the medical intensive care unit (MICU) on day 11 of her hospitalization. Cefepime was given as empiric therapy for febrile neutropenia. Pulmonary invasive aspergillosis was diagnosed. On day 16 of hospitalization, epileptic activity was confirmed. Valproic acid was initiated. Cefepime was discontinued and meropenem was initiated for treatment of cefepime-resistant pneumonia. Serum valproic acid levels decreased to subtherapeutic levels within 24 hours. Meropenem was discontinued and ceftazidime was started on day 22; serum valproic acid levels gradually increased but never reached therapeutic levels again. The patient died of intractable invasive aspergillosis on day 33. A 54-year-old Caucasian man with myelodysplasia was admitted to the MICU for nonconvulsive status epilepticus. Ten days before admission, cefepime had been started empirically for the treatment of neutropenic fever. One day before MICU admission, valproic acid was initiated as treatment for status epilepticus. The next day, serum valproic acid levels were therapeutic; cefepime was switched to meropenem. Serum valproic acid levels decreased within 24 hours and phenytoin was added. On day 4, the patient's serum valproic acid levels decreased further and meropenem was discontinued. Although the valproic acid dosage was increased, valproic acid levels did not return to the therapeutic range. The patient died on day 11.

CONCLUSION

Following cefepime therapy, a clinically important interaction between meropenem and valproic acid occurred in two critically ill patients with new-onset status epilepticus.

Preventive treatment of migraine

Migraine is a common episodic pain disorder, the treatment of which can be acute to stop an attack or preventive to reduce the frequency, duration or severity of attacks. Preventive treatment is used when attacks are frequent or disabling. Many different medication groups are used for preventive treatment, including beta-blockers, antidepressants and antiepileptic drugs. Their mechanisms of action include raising the threshold to migraine activation, enhancing antinociception, inhibiting cortical spreading depression, inhibiting peripheral and central sensitization, blocking neurogenic inflammation and modulating sympathetic, parasympathetic or 5-HT tone. In this article, I review evidence of the effectiveness of migraine preventive drugs. I also discuss the setting of treatment priorities.

Safety and tolerability of mood-stabilising anticonvulsants in the elderly

The authors review current research on the safety and tolerability of anticonvulsant medications used for individuals over the age of 60 years with affective disorders, agitation and other psychiatric disorders. Three anticonvulsants currently approved in the US for treatment of bipolar affective disorder are reviewed: valproate, lamotrigine and extended-release carbamazepine. The authors discuss the pharmacokinetics, pharmacodynamics, drug-drug interactions and the impact of ageing for each drug. There are few studies of anticonvulsant medications in elderly patients with bipolar disorder or other psychiatric conditions. Therefore, the authors summarise adverse events of greatest prevalence and/or greatest severity based on data derived predominately from studies of geriatric patients with epilepsy and/or other non-psychiatric indications. Guidelines are offered for the safe use of these medications in the elderly, based on research literature.

Bipolar affective disorder: advances in genetics and mood-stabilising medication

The lifetime prevalence of bipolar affective disorder is between 1 % and 2%. This educational review paper focuses on two areas of interest and relevance to trainees preparing for the membership examination of the Royal College of Psychiatrists: (a) advances in the genetics of bipolar affective disorder; and (b) mood-stabilising medication in bipolar affective disorder.

The teratology of autism

Autism spectrum disorders affect behaviors that emerge at ages when typically developing children become increasingly social and communicative, but many lines of evidence suggest that the underlying alterations in the brain occur long before the period when symptoms become obvious. Studies of the behavior of children in the first year of life demonstrate that symptoms are often detectable in the first 6 months. The environmental factors known to increase the risk of autism have critical periods of action during embryogenesis. Minor malformations that occur frequently in people with autism are known to arise in the same stages of development. Anomalies reported from histological studies of the brain are consistent with an early alteration of development. Congenital syndromes with high rates of autism include somatic that originate early in the first trimester. In addition, it is possible to duplicate a number of anatomic and behavioral features characteristic of human cases by exposing rat embryos to a teratogenic dose of valproic acid at the time of neural tube closure.

Detection of Purkinje cell loss following drug exposures to developing rat pups using reverse transcriptase-polymerase chain reaction (RT-PCR) analysis for calbindin-D28k mRNA expression

A technique is described that allows for the identification and quantification of Purkinje cell loss in cerebellum subsequent to developmental toxic exposures. This technique relies upon the extensively validated findings that the Purkinje cell is the only site of expression in the cerebellum of the calcium binding protein calbindin-D28k. Thus, analysis of mRNA expression specific to this protein by comparison to matched controls provides a reliable means of determining whether cell loss has occurred. Purkinje cell loss was induced in rat pups by ethanol exposure on postnatal day (PN) 4 or valproic acid administration to pregnant dams on gestational day 13. Analysis was conducted on PN5 or PN10 and the results compared to parallel groups of pups where the Purkinje cells were counted by traditional means. When compared to matched control rat pups the decrease in calbindin-D28k mRNA expression indicates Purkinje cell loss regardless of whether the cell loss was induced by prenatal valproic acid or postnatal ethanol exposure. The availability of a biochemical alternative to histological cell counting allows for more detailed analyses of the mechanisms of Purkinje cell death induced by these two toxicants, including analyses of the early alterations in signal transduction proteins.

Sodium Valproate versus Propranolol in paediatric migraine prophylaxis

In a randomized clinical trial the effect of Sodium Valproate in pediatric migraine prophylaxis was compared with that of Propranolol. One hundred and twenty patients with common migraine (migraine without aura) aged from 3 to 15 years who met the defined criteria enrolled into the study. Randomly the patients were divided in two groups of A and B, treating with sodium Valproate and Propranolol, respectively. Three phases of baseline period (phase I), titration and adjustment period (phases II) and fixed -dose treatment period (phase III) have been designed. A total of 57 patients in group A, and 58 patients in group B completed all phases of the trial. Seventy two percent of patients in group A and 69% of patients in group B have responded to Sodium Valproate and Propranolol, respectively, as a reduction of more than 50% in headache frequency per month. Further more both drugs have shown efficacy in reducing the severity and duration of headache and also better response to rescue medications (p value <0.01). There was no significant difference in all previously mentioned therapeutic effects between two groups (p value <0.05).

Migraine: preventive treatment

Migraine is a common episodic headache disorder. A comprehensive headache treatment plan includes acute attack treatment to relieve pain and impairment and long-term preventive therapy to reduce attack frequency, severity, and duration. Circumstances that might warrant preventive treatment include: (i) migraine that significantly interferes with the patient's daily routine despite acute treatment; (ii) failure, contraindication to, or troublesome side-effects from acute medications; (iii) overuse of acute medications; (iv) special circumstances, such as hemiplegic migraine; (v) very frequent headaches (more than two a week); or (vi) patient preference. Start the drug at a low dose. Give each treatment an adequate trial. Avoid interfering, overused, and contraindicated drugs. Re-evaluate therapy. Be sure that a woman of childbearing potential is aware of any potential risks. Involve patients in their care to maximize compliance. Consider co-morbidity. Choose a drug based on its proven efficacy, the patient's preferences and headache profile, the drug's side-effects, and the presence or absence of coexisting or co-morbid disease. Drugs that have documented high efficacy and mild to moderate adverse events (AEs) include beta-blockers, amitriptyline, and divalproex. Drugs that have lower documented efficacy and mild to moderate AEs include selective serotonin reuptake inhibitors (SSRIs), calcium channel antagonists, gabapentin, topiramate, riboflavin, and non-steroidal anti-inflammatory drugs.

Inhibition by carbapenem antibiotic imipenem of intestinal absorption of valproic acid in rats

The concomitant use of carbapenem antibiotics with valproic acid has been prohibited because panipenem induced a decrease in plasma concentration of valproic acid in epileptic patients during valproic acid therapy. To clarify the possible mechanism of the carbapenem-valproic acid interaction, we investigated the effect of imipenem on the pharmacokinetic behaviour of valproic acid in rats. Co-administration of imipenem (30 mg kg(-1), i.v.) induced a decrease in the peak plasma concentration of valproic acid after oral administration. However, the imipenem-induced decrease in plasma concentrations of valproic acid was not observed within 60 min after intravenous injection of valproic acid. By utilizing in-situ vascular and luminal perfused small intestine, it was confirmed that absorption of valproic acid from the luminal to the vascular perfusate was decreased in the presence of imipenem (0.5 mM) in the vascular perfusate. The everted gut sac method was used to determine the effect of imipenem on active transport of valproic acid. The accumulation of valproic acid on the serosal side of the intestinal sac against the concentration gradient was reduced by lactic acid that inhibits the carrier-mediated transport of valproic acid across the intestinal brush-border membrane. However, imipenem did not affect the active transport of valproic acid. Therefore, the inhibition by imipenem of valproic acid absorption may be caused by a mechanism different from that of lactic acid. In conclusion, imipenem inhibits the intestinal absorption of valproic acid, which contributes to the decrease in plasma concentration of valproic acid after oral administration.

Efficacy of divalproex therapy for schizoaffective disorder

Schizoaffective disorder is a common, severe, and lifelong illness; however, little is known about the pharmacologic treatment of this mental disorder. Divalproex has proven efficacy in the treatment of bipolar disorder. Therefore, to determine whether divalproex is also effective as adjunctive therapy for schizoaffective disorder, the authors performed a retrospective study of 20 patients in the public mental health system with schizoaffective disorder, bipolar type, who initiated divalproex therapy. The mean maximum dose of divalproex (+/-1 SD) was 1,150 mg (+/-400 mg; range, 500-2,000). The mean peak serum valproic acid level was 61 microg/mL (+/-25 microg/mL; range, 20-92). The overall improvement in Clinical Global Impression Scale scores was observed in 75% (15/20) of the patients (p = 0.0001). None in the sample worsened, and none discontinued divalproex because of side effects. These data suggest that divalproex is well-tolerated and effective as treatment of persistent schizoaffective disorder, bipolar type. Thus, divalproex may be an effective agent in the treatment of schizoaffective disorder as well as bipolar disorder. Controlled prospective trials in patients with schizoaffective disorder are needed to verify these findings.

Divalproex in the treatment of alcohol withdrawal

The present study represents an open-label clinical trial comparing treatment with a benzodiazepine (lorazepam) to divalproex in 11 inpatients with uncomplicated alcohol withdrawal syndrome. The trial used the Clinical Institute Withdrawal Assessment for Alcohol-Revised (CIWA-Ar) scale. There were no significant differences in demographics or substance use parameters between the divalproex group (n = 6) or the lorazepam group (n = 5). A significant Group x CIWA-Ar score interaction [F(8,72) = 2.57, p < or = .01] was confirmed and further substantiated by a quadratic trend component for the interaction [F(1,9) = 24.9, p < or = .001]. This preliminary study supports further investigation of divalproex in the treatment of alcohol withdrawal.

Comprehensive review of the psychiatric uses of valproate

The therapeutic effects of valproate in psychiatric conditions are most substantially recognized in bipolar disorder. However, this well-tolerated medication may be beneficial in the treatment of other mental illnesses. In this article, the authors comprehensively review studies of valproate as treatment for psychiatric conditions, including bipolar, depressive, anxiety, and psychotic disorders; alcohol withdrawal and dependence; tardive dyskinesia; agitation associated with dementia; and borderline personality disorder. Valproate shows the most promising efficacy in treating mood and anxiety disorders, with possible efficacy in the treatment of agitation and impulsive aggression, and less convincing therapeutic response in treating psychosis and alcohol withdrawal or dependence. The authors conclude with a brief summary of its mechanism of action and therapeutic spectrum.

Contributions of dam and conceptus to differences in sensitivity to valproic acid among C57 black and SWV mice

To ascertain the relative contributions of genotypes of conceptus and dam to developmental toxicity occasioned by valproic acid (VPA), crosses were established between resistant C57BL/6JBk (C, C57) and susceptible SWV/Bk (S, SWV) strains of mice. These included matings of pure lines, reciprocal outcrosses, and reciprocal backcrosses with F1 hybrids. At 8 d:12 h +/- 5 h, for each mating, 0, 500, or 600 mg/kg aqueous VPA was injected ip. Fetuses were examined on gestation day (gd) 18 for exencephaly (the paradigmatic anomaly), other abnormalities, mortality, litter size, and fetal weight. At 600 mg/kg, sensitivity to exencephaly induction in all cases was that of the dam, regardless of sire. Thus exencephaly here seems to be largely a function of the uterine environment produced by the maternal genotype. This inference is confirmed in backcrosses where F1-dams x S-sires and F1-dams x C-sires produced-identical outcomes, and S-dams x F1-sires produced much higher frequencies of exencephaly than C-dams x F1-sires. For prenatal mortality, the genotypes of both dam and conceptus appear to be important determinants. Fetal contribution is inferred from the observations that S-dam x S-sire matings produced a much higher frequency of mortality than S-dams x C-sires, and C-dams x C-sires produced higher mortality than C-dams x S-sires. Therefore, heterozygosity of the conceptus was protective. Among backcrosses, fetal determination of sensitivity to mortality is also seen by the observation that F1-dams x C-sires produces the same fetal mortality as C-dams x F1-sires. The contribution of uterine environment is seen in the observation that matings of S-dams x C-sires resulted in higher fetal mortality than did those with C-dams x S-sires. Therefore, identical conceptuses in different dams showed different levels of fetal loss. Thus exencephaly response appears to be largely controlled by genes active in the dam, and mortality as a result of a multigenic outcome with contributing genes active in both conceptus and dam. The data also suggest that SWV pure-line dams make a contribution to prenatal mortality not seen in C57 or F1 dams. Mean litter size among VPA-exposed litters showed high variability in pure lines and outcrosses. In backcrosses, F1 dams produced larger litters than pure line dams, arguing for heterosis as a contributor to this parameter. Reduction in litter size occasioned by VPA exposure was great in pure line dams and nonexistent in F1 dams. The SWV dams crossed with F1 sires were the only group among the backcrosses to show reduction of litter size, providing further confirmation of the increased sensitivity of pure-line (i.e., homozygous) SWV dams to VPA exposure. Fetal weight seems to be a function of uterine environment because female SWV produced conceptuses with lower fetal weight in all crosses, and produced a greater reduction in fetal weight attributable to VPA exposure than C57 or F1 dams. Fetal weight did not correlate closely with litter size, suggesting that a lower fetal weight may be a strain characteristic, as are exencephaly induction and prenatal mortality in response to VPA. Differences in sensitivity to VPA insult are seen for all parameters investigated with SWV dams being the most sensitive, but mechanisms seem to differ for a number of the endpoints.

Mood stabilizers and anticonvulsants

This article provides pediatricians and other clinicians who treat children and adolescents with a working knowledge of mood stabilizers and their potential uses in children and adolescents with mood and behavior disorders. Mood stabilizers are ubiquitous agents that are often effective in the treatment of children and adolescents with bipolar disorders or conduct disorders and mentally retarded patients with aggressive behavior. The authors' also discuss mechanisms of action, pharmacokinetics, dosing, drug interactions, and potential uses. Following these medication details, specific information concerning the diagnosis and treatment of several child and adolescent mood and behavior disorders, and in which treatment with mood stabilizers may be helpful, is presented.

Assessment and treatment of bipolar disorder in the elderly

The aetiology of late-onset bipolar disorder is heterogeneous because the disease is more likely to have a secondary (i.e. a medical disorder or medication-induced) cause in older than in younger patients. Elderly patients with bipolar disorder typically require lithium dosages that are 25 to 50% lower than those used in younger individuals. Information on the use of valproic acid (sodium valproate) in elderly patients with bipolar disorder is limited but encouraging. In contrast, there is virtually no information regarding the use of carbamazepine or other drugs in this patient group. Electroconvulsive therapy is well tolerated by older people and can be useful for these patients.

Naturalistic experience with the use of divalproex sodium on an in-patient unit for adolescent psychiatric patients

This paper focuses on the importance of data collected not only from controlled clinical trials, but also from naturalistic treatment experience. In particular we examine the use of divalproex sodium either as monotherapy or as part of combined therapy on an in-patient ward for adolescents aged 13-18 years. All admissions in which divalproex sodium use was attempted (n=36) were analysed over a 1-year period. The most common use was in patients with a mixed-presentation bipolar disorder (n=16), followed by patients with major depression (n=7), mania (n=4) or psychoses not otherwise specified (n=4). Divalproex sodium use was evaluated in the control of mania, psychosis, agitation, mood swings, aggression and/or anxiety. Overall, the use of divalproex sodium was associated with a marked improvement along all psychopathological variables in the vast majority of patients. Few side-effects or medical complications were noted. We believe that divalproex sodium is a potentially useful drug in adolescent patients with varying forms of psychopathology.

An open trial of valproate for agitation in geriatric neuropsychiatric disorders

The authors assessed the efficacy, tolerability and safety of open valproate administration in a group of elderly patients with agitation and neuropsychiatric disorders (N = 13), most of whom had dementia (n = 12). Dosing was individualized according to the response of target symptoms and side effects. Clinical Global Impression of Change (vs. baseline) measured efficacy. This open treatment suggested that valproate reduced agitated behaviors in some patients, and is well tolerated; thus, results warrant a larger, randomized, placebo-controlled study.

A comparison of patient-rated burden and incidence of side-effects: lithium versus valproate

The purpose of the study was to determine if patients receiving valproate perceived a lesser burden than patients receiving lithium, and to determine the incidence of side-effects. Psychiatric inpatients with an affective component to their illness, receiving either lithium or valproate, were asked to complete several questionnaires, one of which was a newly developed visual-analogue scale to assess patient-rated level of burden. The scores were analyzed by Student's t-test, and were also used to determine if any correlations existed. Twenty-nine patients were analyzed, and the patient-rated level of burden was found to be 1.4± 1.3 for lithium and 1.2± 1.6 for valproate; (P=0.1, not significant). The mean numbers of side-effects reported were 12.3 ± 6.7 for lithium and 18.7 ± 13.4 for valproate; (P=0.1). No correlation relationships were detected. We concluded that there was no difference in level of burden, and that burden scores could not be correlated with any variables. Similar studies should be conducted to assess patient preferences, with the hopes of increasing compliance and minimizing rehospitalizations.

A double Weibull input function describes the complex absorption of sustained-release oral sodium valproate

The pharmacokinetics of valproic acid after oral administration of sustained-release formulations were studied in 12 healthy volunteers. The objective of the present study was to find an appropriate mathematical model to describe the complex drug intake process. The concentration of valproic acid in plasma was measured by HPLC. For each subject, during the input process a double peak phenomenon was observed, the plasma concentrations were fitted according to a single or a double Weibull input function, and then a first-order elimination rate was used to describe the observed data. The Weibull model was considered as an approximation of the overall process. The mean peak plasma concentration, 34.6 +/- 8.9 mg/L, was reached after 8.6 +/- 2.7 h. A single Weibull function adequately described the observed data for three subjects; the mean Weibull parameters were td (the time necessary to transfer 63% of the administered drug into the systemic circulation) of 7.87 +/- 3.53 h and gamma (shape) of 1.16 +/- 0.66. A double Weibull input function was used for nine subjects; the mean Weibull parameters were td1 = 2.35 +/- 1.18 h and td2 = 9.36 +/- 4.47 h and gamma 1 = 1.77 +/- 2.27 and gamma 2 = 3.68 +/- 3.26. The mean half-life value of the elimination phase was 14.4 +/- 4.6 h.

Influence of food intake on the pharmacokinetics of a sustained release formulation of sodium valproate

The effect of food intake on the pharmacokinetics of DEPAKINE CHRONO 500 mg (Sanofi, France), a sustained release formulation containing 333 mg sodium valproate and 145 mg valproic acid, was studied in 12 young healthy female volunteers. Relative to fasting conditions (F), when the tablet was given at the midpoint of the breakfast (NF), the maximum concentration (F: 34.6 +/- 8.9 micrograms ml-1 and NF: 40.9 +/- 7.3 micrograms ml-1; p = 0.014) and the mean cumulative amount absorbed up to time 6 h (F: 76.3 +/- 11.8% and NF: 90 +/- 10.4%; p = 0.0099) were significantly increased. Nevertheless, the extent of absorption (F: 46.7 +/- 9.9 mg l-1; NF: 48.7 +/- 7 mg l-1) was not significantly affected. There was no change in the area under the curve (1129 micrograms.h ml-1), in the mean residence time (28 h), or in the elimination half-life (16 h). On the basis of this study, the question as to whether DEPAKINE CHRONO should be administered to subjects in the fasting or non-fasting state would not appear to be a major consideration when deciding on the regimen.

Magnesium valproate attenuates hyperactivity induced by dexamphetamine-chlordiazepoxide mixture in rodents

A mixture of dexamphetamine and chlordiazepoxide induces hyperactivity in both mice and rats. This type of hyperactivity has been proposed as an animal model of mania. Magnesium valproate itself had little influence on the activity of normal mice and rats. Acute pretreatment of mice with magnesium valproate (75-300 mg/kg p.o., 37.5-150 mg/kg i.v.) attenuated the mixture-induced hyperactivity. Pretreatment of rats with a single dose of magnesium valproate (75-300 mg/kg, p.o. or i.p.) also counteracted the locomotor hyperactivity caused by the mixture. The effects of magnesium valproate in the mixture-treated mice and rats could be abolished by bicuculline and picrotoxin, but not isoniazid. These findings suggest that the antimanic effect of valproate may be related to its ability to enhance the postsynaptic effects of gamma-aminobutyric acid (GABA).

Plasma protein binding kinetics of valproic acid over a broad dosage range: therapeutic implications

The aim of the study was to characterize, from the relationship between total and free serum levels of valproic acid obtained over a broad dosage range (10-50 mg/kg), the parameters defining the in-vivo kinetic behaviour of the binding of valproic acid to plasma proteins, their pharmacokinetic and clinical repercussions, and their application to therapeutic drug monitoring (TDM). The study was performed in nine healthy adults (20-35 years) who were given doses of 1000 (group A), 2000 (group B) and 3000 mg (group C) of sodium valproate according to a compensated cross-over design, simultaneously determining the total and free serum levels of valproic acid over a 24-h period. The mean free fraction increases with dose, although this increase is only significant (P < 0.05) for the highest dose (3000 mg). The variation in the free fraction of valproic acid begins to become significant (P < 0.05) at a total drug concentration above 100 mg/l. The mean values of the dissociation constant (K) and binding sites (n) were 460 mumol/l and 1.79, respectively, showing a variability of 86.6 and 38.7%, respectively, and a residual variability of 13.0%. Significant differences (P < 0.05) were found for the total plasma clearance (Cl) but not for the intrinsic plasma clearance (Clu) values, despite their tendency to decrease with the dose. If TDM is to be used for valproic acid, it is the free serum levels that should be determined, especially if high doses are administered, because the total serum levels are not a true reflection of the free ones, as is the case of other anti-epileptic drugs.

Valproate treatment of panic disorder and lactate-induced panic attacks

Several lines of evidence suggest that the anticonvulsant drug valproate may have antipanic properties: (1) It enhances gamma-aminobutyric acid activity in the brain; (2) it has anxiolytic effects in animal models of anxiety; and (3) it has been reported to be effective in panic disorder in several preliminary studies; however, valproate has not been studied in the prevention of lactate-induced panic attacks. Sixteen patients with panic disorder underwent a lactate infusion followed by a 28-day treatment period with valproate and subsequent rechallenge with lactate. Response was measured by change in panic attack frequency and Hamilton Anxiety Scale (HAS) scores and by the ability of valproate to block lactate-induced panic on rechallenge. Of the 14 patients completing the 28-day trial, 10 (71%) experienced a greater than 50% reduction in the weekly frequency of panic attacks. Six (43%) had complete remission. HAS scores dropped significantly from a baseline mean of 30.8 +/- 9.4 (SD) to 12.6 +/- 7 after 4 weeks of treatment. Valproate blocked reinduction of panic symptoms on lactate rechallenge in 10 (83%) of 12 patients who had initially experienced panic symptoms on initial infusion. The significant reduction in spontaneous panic attacks and the blockade of lactate-induced panic symptoms by valproate support earlier studies suggesting that the drug may be an effective treatment for panic disorder.

Valproic acid-induced spina bifida: a mouse model

Prenatal exposure to the antiepileptic drug valproic acid (VPA) has been associated with the formation of spina bifida aperta, meningocele, and meningomyelocele in the human. Until now, a direct relationship between VPA application and spina bifida has not been experimentally demonstrated. VPA was known only to induce exencephaly in mice, a defect of the anterior neural tube. Maximal sensitivity toward production of this defect was on day 8 of gestation (plug day = day 0). The closure of the posterior neuropore occurs later in the development of mice than the closure of the anterior neuropore. To investigate whether there is a direct relationship between VPA application during pregnancy and induction of spina bifida in mice, we administered various doses of the drug on day 9 of gestation, at three time intervals (at 0, 6, and 12 hr). This administration of VPA produced spina bifida aperta and spina bifida occulta in mice. High doses of VPA (3 x 450 and 3 x 500 mg/kg) induced a low rate of spina bifida aperta in the lumbosacral region. High incidences of spina bifida occulta, a less serious form of spina bifida, were induced with lower doses. This malformation was demonstrated in double-stained fetal skeletons by measurements of the distance between the cartilaginous ends of each vertebral arch. The occurrence of this defect and its localization was dose-dependent. The lumbar region was affected by all doses investigated (3 x 300, 3 x 350, 3 x 400, 3 x 450, and 3 x 500 mg/kg). The sacral/coccygeal region was affected additionally, but with higher doses (3 x 400, 3 x 450, and 3 x 500 mg/kg). A comparison of the results obtained with day 16 and 17 control fetuses showed that the pattern of gaps present in the lumbar and sacral region of the spinal cord in treated groups was drug-specific and not related to a developmental delay. Our results indicate that multiple administrations of VPA on day 9 of gestation in mice result in a low incidence of spina bifida aperta and a high incidence of spina bifida occulta, and provides a relevant model for the study of human spina bifida defects.

Probable interaction of sodium divalproex with benzodiazepines

1. After drug discontinuation and 1 week placebo washout, 12 patients with panic disorders received, for 6 weeks, either placebo or sodium divalproex. During 6 consecutive weeks, alternate medication was given. 2. Severity of panic and anxiety attacks was improved only in patients receiving sodium divalproex as a first medication. 3. Protracted benzodiazepine effects may occur in the dichotomous antipanic activity of sodium divalproex.

Excipients in valproic acid syrup may cause diarrhea: a case report

A 5-year-old child receiving valproic acid syrup for seizure control developed diarrhea probably from the excipient ingredients. Each 5 mL of valproic acid syrup contains sucrose 3 g, glycerin 0.75 g, and sorbitol 0.75 g, providing daily amounts of 36, 9, and 9 g of sucrose, glycerin, and sorbitol, respectively. The diarrhea resolved when the child was switched to another valproic acid product. Clinicians should be aware of potential problems that may occur from excipient ingredients in pharmaceutical products when evaluating adverse effects of medications.

Fatal hepatocerebral syndrome in siblings discordant for exposure to valproate

Occurrence of a progressive encephalopathy with seizures in siblings was associated with hepatic pathology. One of these patients was exposed to valproate (VPA) and developed hepatic necrosis, confirmed at autopsy. The other had not been exposed to VPA, and her hepatic lesions at autopsy were less severe. The liver pathology in both was within the range described in previous cases of liver disease attributed to VPA. These facts and the otherwise similar course of their disease suggests that in these patients, and probably in other cases of fatal liver failure attributed to VPA, the drug actually either had no effect or acted only to increase the severity of the preexisting hepatic component of the hepatocerebral disorder.

[Epilepsy at a psychiatric hospital]

Epilepsy was surveyed in the largest psychiatric hospital in the Santa Catarina State, southern Brazil. This establishment was designed for one thousand long-term beds but at the time of the survey there were 1126 inpatients. Diagnosis ranged from anxiety neurosis to schizophrenia although patients with epilepsy, with or without psychiatric symptoms were also admitted. The following aspects were analyzed: prevalence of epilepsy, seizure types, antiepileptic drug treatment and psychiatric diagnosis. 171 patients with epilepsy were identified (prevalence 152/1000), generalized tonic clonic attacks were the commonest seizure type and polytherapy was the standard treatment. In at least 85 of the epileptic patients there was no reason for prolonged institutionalization in a psychiatric environment. Moreover, most of the sample were prescribed large amounts of sedative drugs. A multidisciplinary approach and outpatients services are urgently required to improve the prognosis and well-being of patients with epilepsy who are referred to psychiatric care.

Psychiatric Uses of Anticonvulsants

Anticonvulsants are being used for psychiatric indications with increasing frequency. The potential indications for carbamazepine (CBZ), valproic acid (VPA), clonazepam, and phenytoin are reviewed, with emphasis on double-blind controlled studies where available. Dosage guidelines, adverse effects, and monitoring parameters are reviewed for each of these drugs. The pathophysiological basis for anticonvulsant effectiveness is presented for mood disorders and aggression. CBZ and VPA represent second and third line agents after traditional lithium therapy in bipolar disorder. Clonazepam may be effective in the acute treatment of manic agitation. These alternative agents, when used for appropriate indications, may help the clinician manage the treatment-resistant manic patient. CBZ is also effective for the treatment of aggression and potentially effective for alcohol withdrawal.

The effect of carbamazepine on valproic acid disposition in adult volunteers

1. Pharmacokinetic parameters for valproic acid (VPA) were determined before and following 2 weeks of carbamazepine (CBZ) administration in five healthy male volunteers. Mean VPA dosage was 16.4 mg kg-1 day-1. CBZ dosage was started at 100 mg twice daily and increased after 1 week to a total daily dose of 300 mg. 2. After CBZ administration, mean VPA plasma clearance increased from 0.90 +/- 0.18 s.d. to 1.26 +/- 0.24 l h-1 (P less than 0.05) as did clearance of free VPA (20.8 +/- 7.6 to 37.0 +/- 13.6 l h-1). Mean VPA elimination rate constant increased from 0.051 +/- 0.011 to 0.067 +/- 0.011 h-1 (P less than 0.05) after CBZ administration. 3. Mean area under the serum concentration vs time curve decreased from 675.0 +/- 130.5 to 475.7 +/- 75.7 mg l-1 h (P less than 0.05) after CBZ administration. Mean serum VPA half-life decreased from 14.0 +/- 2.4 to 10.6 +/- 1.4 h (P less than 0.05). Mean serum VPA trough concentrations decreased from 44.0 +/- 16.7 to 27.0 +/- 10.4 micrograms ml-1 (P less than 0.05). 4. A significant change was not observed in the mean VPA volume of distribution after CBZ coadministration suggesting that enzyme induction rather than a competition for plasma protein binding sites was involved in this interaction. 5. Despite the increased clearance of VPA, the urinary recovery of VPA or conjugate did not increase after CBZ administration.

Effect of valproate on renal metabolism in the intact dog

Valproate is an antiepileptic drug known to induce hyperammonemia in humans. This hyperammonemia might result from a reduced detoxification of ammonium in the liver and/or from an accelerated renal ammoniagenesis. Six dogs with normal acid-base equilibrium and eight dogs with chronic metabolic acidosis were infused with valproate directly into their left renal artery in order to obtain arterial concentrations around 3 to 4 mM. The arterial ammonium concentration rose only in chronically acidotic dogs, whereas the lactate concentration and the lactate/pyruvate ratio increased in both groups. The urinary excretion of lactate and pyruvate increased markedly but the urinary excretion of other relevant metabolites remained minimal. Renal glutamine utilization and ammonium production were not changed by valproate administration in normal dogs but increased modestly in acidotic dogs. However, renal lactate utilization was drastically reduced and in fact, changed into a net production of lactate. Valproate strikingly reduced the renal cortical concentrations of glutamine, glutamate, alphaketoglutarate and citrate, and more modestly those of malate, oxaloacetate, aspartate, alanine and ATP. By contrast, the tissue lactate concentration and the lactate/pyruvate ratio were markedly increased. In experiments with brush border membrane vesicles, valproate inhibited the lactate transporter. These results suggest that high concentrations of valproate drastically inhibited the proximal reabsorption and the proximal and distal oxidation of lactate and pyruvate. Valproate probably became itself a significant energetic substrate for the kidney.

The combined use of sodium valproate and metyrapone in the treatment of Cushing's syndrome

We have investigated the combined use of metyrapone and sodium valproate in the treatment of five cases of dexamethasone-suppressible Cushing's disease and one case with dexamethasone non-suppressible disease. Metyrapone alone reduced 24 h urinary free cortisol (UFC) and plasma cortisol concentrations. Addition of sodium valproate to metyrapone produced a further reduction in these values in five of six patients with a reduction in plasma ACTH in three of five patients who had dexamethasone-suppressible disease. Plasma 11-deoxycortisol increased markedly on metyrapone. However, addition of valproate produced a further rise in 11-deoxycortisol values in four of five patients including the patient with dexamethasone non-suppressible disease. The results suggest that valproate may be a useful addition to metyrapone in the medical treatment of some patients with Cushing's syndrome and that it may have an action both at the hypothalamus and peripherally.

Treatment of childhood epilepsy with rectal valproate: case reports and pharmacokinetic study

Two children with status epilepticus were treated successfully by the rectal administration of valproate (VPA), and complete seizure control was obtained in one patient without severe side effects. In addition, there was no essential difference in pharmacokinetics between rectal and oral administration of VPA as determined by computerized simulation of plasma concentration data of VPA after rectal administration in two healthy adults or an epileptic child. Although these findings suggest that the early absorption of VPA within 30 minutes of rectal administration is slightly more rapid than that of oral administration, rectal VPA seems to be unsuitable for the first choice in the treatment of status epilepticus, since it has not so immediate effects as intravenous administration of DZP.