Review of valproate monotherapy in the treatment of generalized tonic-clonic seizures

Long-term safety, tolerability, and efficacy of magnesium valproate versus sodium valproate in acute seizures

Objectives: To evaluate the safety, tolerability and efficacy of magnesium valproate and sodium valproate as monotherapies in patients with epilepsy in China.Methods: We recruited patients admitted with seizures over a two-year period. All patients underwent early neurological assessments, electroencephalogram testing, and neuroimaging. The treatments received at baseline and at one year of follow-up were compared.Results: In total, 175 patients were included. The retention rates of the magnesium valproate and sodium valproate treatments were 73.1% and 64.2%, respectively. The main cause of discontinuation was the development of intolerable adverse events. The retention rate and total effective rate in the magnesium valproate group were significantly higher than those in the sodium valproate group (73.1% and 70.2% versus 64.2% and 47.2%, respectively). The safety endpoints included 120 patients (magnesium valproate: n = 67; sodium valproate: n = 53). The incidence of adverse events in the magnesium valproate group was significantly lower than that in the sodium valproate group (30% versus 51%).Conclusions: Magnesium valproate treatment shows favorable safety and tolerability and is associated with markedly improved seizure control. Ideally, future large, prospective, randomized, and double-blind studies are needed to confirm these findings.

Valproic acid but not D-cycloserine facilitates sleep-dependent offline learning of extinction and habituation of conditioned fear in humans

The effectiveness of D-cycloserine (DCS), an N-methyl-D-aspartate glutamate receptor partial agonist, and valproic acid (VPA), a histone deacetylase inhibitor, in facilitating the extinction of fear-conditioned memory has been explored in humans and animals. Here, we confirmed whether DCS (100 mg) and VPA (400 mg) act in off-line learning processes during sleep or waking, for further clinical application to anxiety disorders and posttraumatic stress disorder (PTSD). We performed a randomized, blind, placebo-controlled clinical trial in 90 healthy adults. Visual cues and electric shocks were used as the conditioned stimulus (CS) and unconditioned stimulus (US), respectively. The extinction effect was observed not in simple recall after the extinction of coupled CS-US, but was observed in the post-re-exposure phase after unexpected re-exposure to reinstatement CS-US coupling. Newly acquired conditioned fear was also eliminated or habituated by DCS and VPA administration, in line with previous findings. Furthermore, VPA facilitated the off-line learning process of conditioned fear extinction and habituation during sleep, while DCS facilitated this process during waking. These novel findings suggest that DCS and VPA might enhance exposure-based cognitive therapy for anxiety disorders and PTSD by reducing the vulnerability to reinstatement and preventing relapses of fear-conditioned responses, and provide evidence for a peculiarity of the sleep-dependent off-line learning process for conditioned fear extinction. This article is part of a Special Issue entitled 'Cognitive Enhancers'.

Effect of D-cycloserine and valproic acid on the extinction of reinstated fear-conditioned responses and habituation of fear conditioning in healthy humans: a randomized controlled trial

RATIONALE

Although the effects of D: -cycloserine (DCS) and valproic acid (VPA) on the facilitation of the extinction of fear-conditioned memory have been elucidated in animals, these effects have not been clearly confirmed in humans.

OBJECTIVE

This study aimed to determine the effect of DCS (100 mg) and VPA (400 mg) on the facilitation of the extinction and acquisition of fear-conditioned memory in humans.

METHODS

We performed a randomized, blind, placebo-controlled, four-arm clinical trial in 60 healthy adults. Visual cues and electric shocks were used as the conditioned stimulus (CS) and unconditioned stimulus (US), respectively.

RESULTS

The extinction or acquisition effect was not observed in the simple recall after the extinction or acquisition of coupled CS-US; however, the extinction and habituation effects but not the acquisition effects were presented after the unexpected re-exposure of coupled CS-US (reinstatement stimuli). Extinction and habituation effects were facilitated by either a single dose of DCS or VPA or a combination of DCS and VPA. However, we did not observe the expected synergistic effect of the combined treatment on the extinction or habituation of fear conditioning.

CONCLUSION

A single dose of DCS or VPA might enhance exposure-based cognitive therapy of anxiety disorders by reducing the vulnerability to reinstatement and preventing relapses of fear-conditioned responses.

Modern methods for analysis of antiepileptic drugs in the biological fluids for pharmacokinetics, bioequivalence and therapeutic drug monitoring

Epilepsy is a chronic disease occurring in approximately 1.0% of the world's population. About 30% of the epileptic patients treated with availably antiepileptic drugs (AEDs) continue to have seizures and are considered therapy-resistant or refractory patients. The ultimate goal for the use of AEDs is complete cessation of seizures without side effects. Because of a narrow therapeutic index of AEDs, a complete understanding of its clinical pharmacokinetics is essential for understanding of the pharmacodynamics of these drugs. These drug concentrations in biological fluids serve as surrogate markers and can be used to guide or target drug dosing. Because early studies demonstrated clinical and/or electroencephalographic correlations with serum concentrations of several AEDs, It has been almost 50 years since clinicians started using plasma concentrations of AEDs to optimize pharmacotherapy in patients with epilepsy. Therefore, validated analytical method for concentrations of AEDs in biological fluids is a necessity in order to explore pharmacokinetics, bioequivalence and TDM in various clinical situations. There are hundreds of published articles on the analysis of specific AEDs by a wide variety of analytical methods in biological samples have appears over the past decade. This review intends to provide an updated, concise overview on the modern method development for monitoring AEDs for pharmacokinetic studies, bioequivalence and therapeutic drug monitoring.

D-cycloserine facilitates procedural learning but not declarative learning in healthy humans: a randomized controlled trial of the effect of D-cycloserine and valproic acid on overnight properties in the performance of non-emotional memory tasks

Although D-cycloserine (DCS), a partial agonist of the N-methyl-d-aspartate (NMDA) receptor, and valproic acid (VPA), a histone deacetylase inhibitor, have been investigated for their roles in the facilitation of emotional learning, the effects on non-emotional declarative and procedural learning have not been clarified. We performed a randomized, blind, placebo-controlled, 4-arm clinical trial to determine the effects of DCS and VPA on the overnight properties of declarative and procedural learning in 60 healthy adults. Subjects were orally administrated a placebo, 100 mg DCS, 400 mg VPA, or a combination of 100 mg DCS and 400 mg VPA before they performed declarative and procedural learning tasks. Subjects then had their performance retested the following day. We observed that DCS facilitated procedural but not declarative learning and that VPA did not contribute to learning. Surprisingly, however, VPA attenuated the enhancement effect of DCS when coadministered with it. These results suggest that DCS acts as an enhancer of hippocampus-independent learning and that VPA may have an extinguishing pharmacological effect on excitatory post-synaptic action potentials that NMDA receptors regulate within procedural learning.

Solid-state forms of sodium valproate, active component of the anticonvulsant drug epilim

The results of the first detailed and systematic investigation of the solid-state forms of sodium valproate, one of the most potent and widely used anticonvulsant medicines, are presented. By using wet and dry methods, eight solid forms of varying stability in air were obtained and characterized. Three extremely hygroscopic polycrystalline hydrates, Na(C8H15O2) X H2O (form A), Na(C8H15O2) X xH2O (form B), and Na(C8H15O2) X yH2O (form D), three acid-stabilized stoichiometric solvates, Na3(C8H15O2)3(C8H16O2)H2O (form C), Na(C8H15O2)(C8H16O2) (form E), and Na3(C8H15O2)3(C8H16O2) X 2H2O (form F), the pure anhydrous salt Na(C8H15O2) (form H), and an additional unstable thermal intermediate Na3(C8H15O2)3(C8H16O2)0.5 (form G) were prepared. Under ambient conditions, forms A and B as well as the commercially available compound appear as very hygroscopic white powders. Form C is less hygroscopic, while forms E and F are stable and are not hygroscopic. Partial stabilization of forms A and B can be achieved by evacuation and pressing, which results in a lower hydrate D, or after a heating-cooling cycle, resulting in crystallization of the anhydrous salt H. Addition of one molecule of valproic acid and saturation with one molecule of water of forms A and B results in the less hygroscopic form C. Addition to form C of a second water molecule affords form F, which is not hygroscopic and is indefinitely stable. The symmetric structure and medium alkyl chain length of the valproate ion are some of the probable reasons for the presence of a number of solid solvates: in its most stable conformation, the valproate ion cannot simultaneously pack efficiently and interact strongly through the negatively charged carboxylate group without leaving voids in the crystalline lattice. The conformational flexibility of the aliphatic chains probably aids the penetration of water molecules, which results in a strong affinity for the absorption of water.

Valproic acid-associated weight gain in older children and teens with epilepsy

This research was undertaken to determine the incidence and predictors of weight gain in older children and teens treated with valproate for epilepsy. Subjects who were 10 to 17 years of age, who began valproate treatment between January 1, 1996, and December 31, 2000, and who had documented weight and height measurements at medication initiation and at least one follow-up visit were retrospectively identified. Exclusion criteria were follow-up <2 months, discontinuation of valproate within 2 months, concurrent therapy with medication known to affect weight, or gastrostomy feeding. Body mass index was calculated at initiation and either discontinuation of valproate or last follow-up and stratified into four categories: underweight, (<fifth percentile), appropriate (fifth to eighty-fifth percentile), potentially overweight (>/=eighty-fifth to ninety-fifth percentile) and overweight (ninety-fifth percentile or higher). Potential predictors of change in body mass index were examined. Mild-to-moderate weight gain was observed in 58% of the 43 subjects treated with valproate (median increase, 2; twenty-fifth to seventy-fifth percentile, 1-6.4). Seventy-nine percent remained in the same body mass index category, and 14% moved up to a potentially overweight or overweight category. The only predictor of an overweight category at follow-up was a potentially overweight or overweight category at initiation (P <0.0002). Two factors tended to predict an increase in body mass index: normal neurocognitive status (P = 0.06) and primary generalized seizure type (P = 0.07).

Biochemical basis of sodium valproate hepatotoxicity and renal tubular disorder: time dependence of peroxidative injury

Mice fed with sodium valproate for 7, 14 and 21 days were evaluated for hepatotoxicity and renal tubular disorder. The drug was administered as an aqueous solution with an increasing concentration up to five days gradually reaching up to 0.71% w/v, which persisted throughout the study period. Mice fed with sodium valproate for 7, 14 and 21 days showed, marked hepatic injury and renal tubular disorder, evidenced by increased levels of malondialdehyde as a measure of lipid peroxidation. Administration of sodium valproate affected the glutathione contents both in liver and kidney tissue at all the three time points. However, this reduction in glutathione concentration was more pronounced in kidney when compared to control group. These results support the hypothesis that lipid peroxidation mediates the effect of sodium valproate on liver and kidney. Furthermore, the valproate induced toxicity is time related and the increase in lipid peroxide levels and depletion of glutathione occur time dependent even if the dose is clinically appropriate.

Evaluation of the antiinflammatory activity of sodium valproate in rats and mice

1. Treatment of rats with sodium valproate (100, 200 and 400 mg/kg i.p.) reduced the paw oedema induced by carrageenan by 36, 15 and 48%, respectively, within 3 h . 2. The effect produced by the higher dose (400 mg/kg) was equivalent to that produced by indomethacin (100 mg/kg). At 100 and 400 mg/kg, sodium valproate decreased the granuloma formation by a significant level. Similar doses of sodium valproate did not affect the rectal temperature in yeast-fevered mice, except with a dose of 200 mg/kg, which showed a significant decrease at 180 and 240 min posttreatment. 3. In comparison, sodium salicylate reduced the hyperthermia very significantly throughout the study period. 4. In normothermic mice, the rectal temperature changed only with a 400 mg/kg dose, but did not respond to lower SV doses. 5. The results indicate that sodium valproate, useful clinically as an epileptic drug, may have a potential therapeutic use as a mild antiinflammatory agent.

Spinal cord infarction: etiology and outcome

We reviewed 44 cases of ischemia and infarction of the spinal cord at two university hospitals. Three patients experienced transient ischemic attacks. Etiologies of completed strokes were diverse and included rupture and surgical repair of aortic aneurysms, aortic dissection, aortic rupture and thrombosis, global ischemia, anterior spinal artery embolism, repair and thrombosis of spinal arteriovenous malformations, hematomyelia, epidural hematoma, cervical osteophytosis, celiac plexus block, systemic lupus erythematosus, coagulopathy, and decompression sickness. Motor function improved in 12 patients, was substantial in only one, and occurred largely within the first 2 to 4 weeks. Favorable ambulatory outcome correlated with improving neurologic examinations and relatively preserved strength in hip abductors and knee extensors. More extensive deficits without initial improvement portended a more severe prognosis. Autonomic dysfunction, pain, paresthesia, and depression were common and impeded recovery in some patients. The mean level of deficit was at T-8 and in cases of global ischemia was at T-9, which leads us to dispute the classical view of a midthoracic watershed zone of ischemic vulnerability near T-4.

The rapid change to monotherapy with valproic acid in children

A review of hospitalized epilepsy patients at Texas Tech University identified 20 children during a 4-year period who had undergone a rapid change from other anticonvulsants to valproate monotherapy. All patients had difficult-to-treat or intractable epilepsy syndromes. In each case, sodium valproate was introduced over a 2- to 4-day period as all other anticonvulsants were withdrawn quickly and sequentially. No acute side effects were seen during hospitalizations, and only one patient reported gastrointestinal complaints. At time of discharge, 12 of the 20 patients were seizure free. Fifteen of the 20 patients were maintained on monotherapy following discharge. By the end of the study period, 12 of the 20 patients showed improvement with valproate, with nine patients experiencing complete seizure control. A rapid switch to valproate monotherapy can be done safely in an inpatient setting.

Efficacy and adverse effects of antiepileptic drugs

One must balance carefully the need for seizure control and the resulting toxicity of the antiepileptic agent. The perfect antiepileptic drug is as yet unavailable; until it is, physicians must be aware of individual variations with regard to drug response and efficacy.