Lack of an effect of valproate concentration on lamotrigine pharmacokinetics in developmentally disabled patients with epilepsy

PURPOSE: to describe the population pharmacokinetics of lamotrigine (LTG) in developmentally disabled (DD) patients with epilepsy and (2) to determine if there is an effect of valproate (VPA) concentration on the extent of the pharmacokinetic interaction between VPA and LTG. METHOD: a NONMEM population analysis of steady-state LTG serum concentrations was conducted in patients receiving LTG either as mono or polytherapy with either an enzyme inducer (IND)-carbamazepine (CBZ), phenytoin (PHT), phenobarbital (PB) or an inhibitor (VPA). RESULTS: sixty-two patients (33.6+/-11.3 years, 47+/-9.9 kg) receiving LTG monotherapy (n=19) or polytherapy with VPA (n=15), inducer(s) (n=32) or both (n=5) were evaluated. LTG dose of 369+/-236 mg per day (8.1+/-5.9 mg/kg per day) achieved LTG plasma concentrations of 6.8+/-3.3 microg/ml. The observed LTG monotherapy, LTG+IND, and LTG+VPA oral clearance (Cl/F) were 0. 69+/-0.2, 1.60+/-0.65 and 0.2+/-0.05 ml/kg per min, respectively. The final LTG Cl/F model was dependent on body weight, concomitant VPA, and either single or multiple inducers. Including the serum concentrations of CBZ, PHT, or VPA in the model, did not significantly improve estimates of Cl/F. CONCLUSION: LTG Cl/F in DD patients is similar to literature values for ambulatory adult patients; however, low weight adult patients have higher elimination rates, as well as an increased response to enzyme induction. VPA inhibition of LTG Cl/F is maximal within the usually accepted therapeutic range for VPA.     

Adding valproate to lamotrigine: a study of their pharmacokinetic interaction

The addition of valproic acid (VPA) to a lamotrigine monotherapy regimen (LTG) results in a decrement of LTG clearance. Whether this effect is related to the dose or concentration at steady state (Css) of VPA is yet to be established. This study was conducted to determine whether the dose or Css of VPA were inversely related to LTG clearance in 28 patients with intractable epilepsy who were treated with a combination of LTG and VPA. Correlations between LTG clearance and the dose and Css of VPA and comparisons of LTG clearance during low and high doses of VPA demonstrated that the degree of inhibition of LTG clearance is independent of the dose and Css of VPA.     

Time course of lamotrigine de-induction: impact of step-wise withdrawal of carbamazepine or phenytoin

OBJECTIVE: The objective of the present analysis is to examine lamotrigine (LTG) pharmacokinetics both during polytherapy with enzyme inducing antiepileptic drugs and to evaluate the time course of de-induction following the step-wise withdrawal of enzyme inducers. BACKGROUND: LTG pharmacokinetics can be significantly influenced by concomitant AEDs, and the addition of enzyme inducers can markedly increase LTG clearance, thereby reducing serum concentrations. A clinically relevant question is how will LTG clearance and resulting plasma concentrations be altered during concomitant enzyme inducer withdrawal/conversion process. DESIGN/METHOD: As part of a previously published, active-control, LTG monotherapy trial, dose and plasma concentration data for LTG, carbamazepine (CBZ) or phenytoin (PHT) were obtained. Following the attainment of a LTG target dose of 500 mg/day, CZB or PHT were withdrawn in weekly 20% decrements. Following inducer withdrawal, LTG was then continued as monotherapy for an additional 12 weeks. Plasma concentrations and daily doses of LTG, CBZ, or PHT were obtained at regularly scheduled study visits during inducer withdrawal and during LTG monotherapy. Pharmacokinetic analysis of the plasma concentration data was done to determine the time-course and effect of inducer plasma concentration on LTG oral clearance (Cl(o)), where LTG Cl(o) was estimated as the dose/concentration ratio. RESULTS: Of the 156 patients enrolled in this trial, 76 were assigned to LTG arm, 43 completed the withdrawal to monotherapy phase with 28 successfully completing the study. In a subset analysis of completers, LTG Cl(o) determined prior to withdrawal of the inducers was significantly greater in patients (n=28) on LTG+PHT (160% increase) than in those (n=48) receiving LTG+CBZ (62% increase): 1.77+/-0.77 vs. 1.06+/-0.41 ml/min/kg, respectively, p=0.017. The significant reduction in LTG Cl(o) occurred only when CBZ plasma concentrations reached approximately 2 microg/ml or PHT plasma concentrations reached zero. CONCLUSIONS: Mean LTG plasma concentrations will approximately double following the withdrawal PHT; however increases of only 60% may occur following the withdrawal of CBZ. Importantly, these data suggest that LTG concentrations would not be expected to increase until the concomitant inducer is almost completely removed.     

An interaction study between the new antiepileptic and CNS drug carisbamate (RWJ-333369) and lamotrigine and valproic acid

PURPOSE: To characterize possible pharmacokinetic interactions between the new antiepileptic drug carisbamate (RWJ-333369) and valproic acid (VPA) or lamotrigine (LTG) following multiple dosing in healthy subjects. METHODS: Two open-label, sequential-design studies were conducted in 24 healthy adults. In Study 1, subjects received carisbamate alone (5 days 250 mg q12h; 5 days 500 mg q12h), then VPA alone (7 days 300 mg q12h; 7 days 500 mg q12h), and then a combination of VPA (500 mg q12h) and carisbamate (5 days 250 mg q12h; 5 days 500 mg q12h). In Study 2, subjects received carisbamate alone as in Study 1, then LTG alone (14 days 25 mg q12h; 14 days 50 mg q12h), and then combination of LTG (50 mg q12h) and carisbamate (3 days 250 mg q12h; 14 days 500 mg q12h). RESULTS: Coadministration of VPA or LTG had minimal effect on carisbamate mean C(max) and AUC(ss) values. Mean VPA-C(max) and AUC(ss) values were approximately 15% lower when given concomitantly with carisbamate. However, the 90% confidence intervals (CIs) for the C(max) and AUC(ss) ratio with/without carisbamate were within the 80-125% equivalence range, C(max) 82-89%; AUC(ss) 81-88%. Mean LTG C(max) and AUC(ss) values were approximately 20% lower when given concomitantly with carisbamate. The 90% CIs with and without carisbamate for LTG C(max) and AUC(ss) were 79-86% and 75-81%, respectively. This modest change is not considered clinically significant. CONCLUSIONS: There were no clinically significant interactions between carisbamate and VPA or LTG. Concomitant administration of carisbamate with VPA or LTG was generally safe and well tolerated.     

Topiramate and lamotrigine pharmacokinetics during repetitive monotherapy and combination therapy in epilepsy patients

PURPOSE: To determine at steady state (in the same group of patients): (a) the pharmacokinetics (PK) of lamotrigine (LTG) with LTG monotherapy, (b) the PK of LTG concomitantly administered with topiramate (TPM) at three escalating TPM doses (100, 200, and 400 mg/day), (c) the PK of TPM at three escalating TPM doses while receiving fixed-dose LTG therapy, and (d) the PK of TPM with TPM monotherapy. METHODS: This was an open-label, sequential, single-group, dose-escalating PK study in which 13 patients with epilepsy not optimally controlled with LTG received stable-dose LTG monotherapy for 2 weeks, followed by stable-dose LTG therapy combined with escalating doses of TPM for 相似文献   

Pregabalin drug interaction studies: lack of effect on the pharmacokinetics of carbamazepine, phenytoin, lamotrigine, and valproate in patients with partial epilepsy

PURPOSE: Pregabalin (PGB) is an alpha2-delta ligand with demonstrated efficacy in epilepsy, neuropathic pain, and anxiety disorders. PGB is highly efficacious as adjunctive therapy in patients with refractory partial seizures. METHODS: Given its efficacy as adjunctive therapy, the potential for interaction of PGB with other antiepileptic drugs (AEDs) was assessed in patients with partial epilepsy in open-label, multiple-dose studies. Patients received PGB, 600 mg/day (200 mg q8h) for 7 days, in combination with their individualized maintenance monotherapy with valproate (VPA), phenytoin (PHT), lamotrigine (LTG), or carbamazepine (CBZ). RESULTS: Trough steady-state concentrations of CBZ (and its epoxide metabolite), PHT, LTG, and VPA were unaffected by concomitant PGB administration. Likewise, PGB steady-state pharmacokinetic parameter values were similar among patients receiving CBZ, PHT, LTG, or VPA and, in general, were similar to those observed historically in healthy subjects receiving PGB alone. The PGB-AED combinations were generally well tolerated. PGB may be added to VPA, LTG, PHT, or CBZ therapy without concern for pharmacokinetic drug-drug interactions.     

Concomitant use of divalproex sodium and lamotrigine in developmentally disabled patients with epilepsy: a retrospective evaluation of efficacy and tolerability

Objective. Epilepsy in institutionalized severe developmentally disabled patients poses a therapeutic challenge. Frequently these patients have multiple seizure (sz) types that are often intractable. Both divalproex sodium (VPA) and lamotrigine (LTG) have demonstrated efficacy. We sought to examine the efficacy of this specific combination in a group of institutionalized, developmentally disabled patients with epilepsy.Methods. Medical and pharmacy records of all patients with developmental disabilities and intractable seizures were reviewed to identify those who had received VPA and LTG. This retrospective evaluation was structured with respect to time frame and outcome measure. Phase 1 consisted of baseline monotherapy with VPA. Phase 2 consisted of titration/dose escalation. Phase 3 was treatment observation period with the combination of both. Seizure frequency and adverse effect data were obtained from nursing or residential staff records. Primary outcome measures were change in seizure frequency between Phases 1 and 3. Additional measures were percentage of patients seizure-free and those with >75% reduction in seizures. A Wilcoxan signed rank test was used for statistical analysis.Results. Of 293 patients, 25 (12M/13F, 31.7+/-10.2 years) had VPA monotherapy following which LTG was added. Mean doses of VPA and LTG were 1474+/-728 and 165+/-111mg/day, respectively. Baseline seizure frequency ranged from 1 to 25 per month. Mean seizure frequency significantly decreased (6.5+/-vs2.0+/-4.0seizures/month, P<0.001). Sixty-four percent of these patients had >/=75% reduction in seizures 28% became seizure-free.Conclusions. The combination of VPA and LTG appears efficacious in this group of developmentally disabled patients with intractable seizures. Rash, which has been associated with this combination, was notably absent and this may reflect the slower titration schedule used.     

Blood homocysteine, folate and vitamin B-12 concentrations in patients with epilepsy receiving lamotrigine or sodium valproate for initial monotherapy

To evaluate whether the administration of lamotrigine (LTG) or valproate (VPA) changes concentrations of plasma total homocysteine (tHcy), plasma and red-cell folate and plasma Vitamin B-12, we measured these indices in a total of 20 patients with epilepsy before and after a 32-week period of monotherapy of LTG or VPA. We found that the 32-week administration of a mean daily dose of 250mg LTG had no significant effect on any of the blood indices. On the other hand, the administration of a mean daily dose of 2070mg of VPA resulted in a 57% increase in plasma Vitamin B-12 concentrations over the baseline value and a 27% decline in plasma tHcy concentrations, although the mechanisms of such changes are unknown. Our data indicate that hyperhomocysteinemia may not be a serious clinical problem among patients with epilepsy, who receive either LTG or VPA.     

How to replace lamotrigine with valproate

If lamotrigine (LTG) has to be replaced with valproate (VPA), this exchange may be complicated by adverse events that result from the complex interaction of both drugs. We report on two cases in which such problems occurred in spite of a cautious switch considering the VPA induced LTG serum increase. The satisfying outcome after a sudden and complete withdrawal of LTG in both cases encouraged us to perform the switch from LTG to VPA systematically by discontinuing LTG abruptly and building up the VPA maintenance dosage very rapidly in the following five consecutive patients who required this exchange. We recommend our abrupt dosage change-over strategy as an easy, safe and cost-effective option.     

Epilepsy and pregnancy: lamotrigine as main drug used

OBJECTIVES: To study the risk of teratogenicity in infants of women with epilepsy. MATERIAL AND METHODS: Prospective data from 1996 to 2000 comprised 147 pregnancies. The most frequent antiepileptic drugs (AEDs) used were lamotrigine (LTG) 35% (n = 51), oxcarbazepine (OXC) 25% (n = 37) and valproate (VPA) 20% (n = 30). Seventy-four per cent (n = 109) received monotherapy. Folic acid supplementation was taken during first trimester by 118 patients (80%). RESULTS: The overall risk of malformations among newborns in the AED-exposed group was 3.1% (n = 4). Two children were born with multiple malformations (VPA monotherapy), two children had ventricular septal defects (one OXC monotherapy, and one OXC and LTG). The risk of malformations was 2.0% in women treated with LTG and 6.7% in women treated with VPA (NS). CONCLUSION: Despite the small number of cases in the study these data indicate that treatment with LTG during pregnancy might be relatively safe. Larger prospective studies are needed to obtain adequate power for statistical analysis.     

Pharmacological outcomes in newly diagnosed epilepsy

The response to antiepileptic drugs (AEDs) has been examined in 780 adult and adolescent patients with newly diagnosed epilepsy presenting with a range of seizure types and epilepsy syndromes over a 20-year period. Carbamazepine (CBZ, n=312), sodium valproate (VPA, n=315), and lamotrigine (LTG, n=249) were the most common AEDs prescribed as monotherapy. More patients with localization-related epilepsies became seizure free with LTG (63%) than with CBZ (45%, P=0.006) or VPA (42%, P=0.006). For idiopathic generalized epilepsies a greater proportion of patients achieved control with VPA (68%) than with CBZ (31%) or LTG (45%). In particular, more patients with juvenile myoclonic epilepsy responded to VPA (75%) compared with LTG (39%, P=0.014). Seizure freedom was achieved with modest or moderate daily doses (median CBZ 400mg, VPA 1000 mg, (LTG) 150 mg) of all three AEDs in the majority of patients achieving remission. Time to first seizure did not differ among these three drugs when given as first treatment. Adverse effects leading to withdrawal were more frequent with CBZ (16%) than with VPA (7%, P=0.03) or LTG (7%, P=0.018). In patients failing initial monotherapy, response to a combination of two AEDs (27%) was not different from that with alternative monotherapy (32%). The majority of patients with newly diagnosed epilepsy responding to treatment did so rapidly and completely with moderate doses of AEDs, with no differences in time to first seizure.     

Tolerability and pharmacokinetics of oral loading with lamotrigine in epilepsy monitoring units

PURPOSE: To investigate the tolerability and pharmacokinetics of oral loading with lamotrigine (LTG) among epilepsy patients after temporary drug discontinuation in an epilepsy monitoring unit. METHODS: We conducted a pilot study among epilepsy patients (18 years or older) receiving maintenance doses of LTG. LTG was discontinued on admission and restarted at the end of epilepsy monitoring. LTG was given as a single oral dose calculated based on the population expected volume of distribution (Vd, 1.0 L/kg) and target blood level on admission. Baseline and serial blood levels of LTG were determined hourly for 10 to 12 h after the loading dose. Outcome measures: (a) frequency of patients with side effects; (b) time to maximum concentration (Tmax), maximum concentration (Cmax), actual volume of distribution, and half-life. RESULTS: Twenty-four patients received a single oral load of LTG (mean, 6.5 +/- 2.7 mg/kg). Overall, LTG loading was well tolerated with no serious adverse events or skin rash observed. Two patients had transient and mild nausea 1 to 2 h after the oral load. The mean estimated pharmacokinetic parameters are as follows: Tmax, 3.1 +/- 2.1 h; Cmax, 8.2 +/- 6.5 mg/L; Vd, 1.1 +/- 1.0 L/kg; clearance, 0.08 +/- 0.08 mg/L/h; half-life, 22 +/- 30 h. All patients reached their target blood levels. CONCLUSIONS: Epilepsy patients temporarily discontinued from LTG can be restarted with a single oral loading dose. This was well tolerated, and therapeutic levels can be achieved within 1 to 3 h.     

Preliminary results on pregnancy outcomes in women using lamotrigine

PURPOSE: In 1992, the International Lamotrigine Pregnancy Registry was initiated to enroll prospectively and to monitor pregnancies exposed to lamotrigine (LTG) for the occurrence of major birth defects. This study presents results as of September 2001 on 168 outcomes exposed to LTG monotherapy and 166 outcomes after pregnancies exposed to LTG polytherapy during the first trimester. METHODS: LTG pregnancy exposures are voluntarily reported to the registry by health care providers before they are aware of each pregnancy outcome. Pregnancy-outcome ascertainment is obtained through subsequent follow-up with the reporting health care provider, and each reported birth defect is reviewed by an expert pediatrician. The percentage with major birth defects in pregnancies with known birth defect status was calculated for LTG monotherapy and for polytherapy stratified by trimester of exposure. RESULTS: The registry identified 334 first-trimester LTG pregnancy outcomes exposed to LTG monotherapy or polytherapy during the first trimester and involving either a live birth with or without a major birth defect or an abortion with a major birth defect. After exposure to LTG monotherapy, the percentage with major birth defects exposed to LTG monotherapy was three (1.8%) of 168 [95% confidence interval (CI), 0.5-5.5%]. There were five (10%) major birth defects observed in 50 outcomes after LTG polytherapy involving valproic acid (VPA; 95% CI, 3.7-22.6%) during the first trimester. The observed proportion of major defects after LTG polytherapy without VPA during the first trimester was five (4.3%) of 116 (95% CI, 1.6-10.3%). No specific patterns of major birth defects in any subgroup or within the registry as a whole were observed. CONCLUSIONS: The sample sizes for individual regimens are too small to rule out small increases in frequency of all major birth defects or even large increases in frequency of rare major birth defects. However, the percentage of outcomes with major birth defects after LTG monotherapy in this study and in another similar pregnancy registry in the United Kingdom did not differ from that reported in the recent literature for women with epilepsy receiving antiepileptic drug monotherapy (4%). The frequency of major malformations after exposures of LTG-VPA is higher than that after the LTG monotherapy or LTG polytherapy regimens without VPA. Although there are published data on frequency of major malformations after VPA exposures in pregnancy, between-study differences in methods and source populations and the wide confidence intervals around the estimate for LTG and VPA limit the utility of comparison with such data, and no conclusions are made at this time about this combination. The continued registration of exposed pregnancies to an exposure registry as early as possible in the pregnancy before any knowledge of the outcome, and before any prenatal testing, will enhance the power of such data.     

Lupus anticoagulant induced by the combination of valproate and lamotrigine

A 5-year-old boy with generalized absence seizures was treated with valproate (VPA), 30 mg/kg/day. One month after VPA introduction, routine examination showed moderate reduction in fibrinogen and prolonged partial thromboplastin time (PTT). The search for lupus anticoagulant (LAC) was negative. After 10 months of VPA treatment, seizures persisted, and lamotrigine (LTG), 2 mg/kg/day, was progressively given with VPA. Seizures disappeared, but PTT was more prolonged than before LTG introduction. The search for LAC was positive, and enzyme-linked immunosorbent assays (ELISAs) for immunoglobulin G (IgG) anticardiolipid antibodies were positive. Serum autoantibody screen and rheumatoid factor were negative; serum complement was normal. LAC eventually disappeared with VPA discontinuation. We believe that LTG may have exacerbated an initially mild immune response induced by VPA without clinical evidence of systemic disease. We therefore suggest that careful surveillance for LAC and systemic disease should be instituted when VPA is used with LTG.     

Comparison of the Steady-State Pharmacokinetics of Topiramate and Valproate in Patients with Epilepsy During Monotherapy and Concomitant Therapy

Summary: Purpose: The steady-state pharmacokinetics of valproate (VPA) and topiramate (TPM) were compared during VPA monotherapy, concomitant VPA and TPM therapy, and TPM monotherapy to evaluate pharmacokinetic interactions. Methods: After a 3-week baseline period, 12 patients receiving VPA monotherapy (500 to 2,250 mg every 12 h) received TPM at three escalating doses (from 100 to 200 to 400 mg every 12 h), each for 2 weeks. Thereafter, the VPA dose was tapered by 25% weekly. Blood and urine samples were collected over 12-h intervals during VPA monotherapy and at the end of each stage of TPM dose escalation and TPM monotherapy. Results: All patients reached TPM monotherapy, and nine achieved satisfactory seizure control for 2 weeks without VPA. TPM plasma peak concentration (C_max) and area under the concentration-versus-time curve during a 12–h dosing interval (AUC_0–12) were slightly higher (17%; n = 8) during TPM monotherapy than during concomitant VPA therapy. TPM oral and renal clearances (n = 8) were 25.9 ± 4.6 and 11.6 ± 3.2 ml/min during TPM monotherapy and were 29.8 ± 4.2 and 12.4 ± 2.7 ml/min during VPA concomitant therapy. VPA AUC_(0–12) decreased (11.3%; n = 10) with the addition of TPM 400 mg every 12 h. VPA oral clearance was 12.8 ± 4.1 ml/min during monotherapy and was 13.8 ± 4.0,14.1 ± 3.9, and 14.5 ± 5.2 ml/min during coadministration of TPM 100, 200, and 400 mg every 12 h, respectively. Cognitive dysfunction, observed in some patients receiving high doses of VPA with TPM, reversed or improved with VPA dose reduction and discontinuation. The lower-than-normal prestudy platelet count measured in one patient increased to normal levels when VPA was discontinued. Conclusions: Because changes in TPM and VPA pharmacokinetics were small, it is unlikely that their concomitant use will have a significant impact on the clinical condition of the patient.     

Sodium valproate versus lamotrigine: a randomised comparison of efficacy, tolerability and effects on circulating androgenic hormones in newly diagnosed epilepsy

We have performed a randomised, prospective study to compare the efficacy and tolerability of sodium valproate (VPA) and lamotrigine (LTG) monotherapy, and their effects on circulating androgenic hormones, in newly diagnosed epilepsy. A total of 225 patients (116 male; median age 35 years, range 13-80 years) were followed-up at 6-weekly intervals until they reached an end-point (12 months' seizure freedom; withdrawal due to intolerable side-effects; lack of efficacy despite adequate dosing). Twelve month seizure-free rates were identical (47%) in the VPA (n=111) and LTG (n=114) treatment arms. More patients taking VPA withdrew from the study due to adverse events (26 VPA versus 15 LTG; p=0.046). Eight patients, all taking VPA, dropped out during the first 6 months due to weight gain. There were no changes in mean serum concentrations of testosterone, sex-hormone binding globulin and androstenedione or in the free androgen index after 6 or 12 months' treatment with either drug in 112 patients who fulfilled the criteria for hormone analysis. No difference in efficacy was found between VPA and LTG in our patients with newly diagnosed epilepsy. LTG appeared to be better tolerated. Neither drug appeared to alter the circulating levels of androgenic hormones.     

Lamotrigine High-Dose Tolerability and Safety in Patients with Epilepsy: A Double-Blind, Placebo-Controlled, Eleven-Week Study

Summary: Purpose: This study was undertaken to evaluate the dose tolerability and safety of a chronic ascending twice-daily (b.i.d.) dosage regimen of 700 mg/day larnotrigine (LTG) and to include determination of the LTG pharmacokinetic profile at doses 500 mg/day in patients receiving concomitant enzyme-inducing antiepileptic drugs (AEDs). Methods: Twelve adult male epileptic patients treated with enzyme-inducing AEDs received 700 mg/day (b.i.d.) oral LTG (n = 8) or placebo (controls, n = 4). For 3 weeks, as outpatients they had their LTG dosage increased from 100 to 400 mg/day. Then, in a clinical research study unit, patients received regimens of 500, 600, and 700 mg/day for 1 week each. Controls received matching placebo in the same sequence. At study end, dosages were tapered in 2 weeks. Follow-up evaluations were made 7 days later. Results: Five LTG patients tolerated 700 mg/day for 1 week. LTG was reduced to 600 mg/day in a patient with mild diplopia and to 500 mg/day in a patient with mild oscillopsia and diplopia. One patient discontinued 300-mg/day therapy with a moderately intense diffuse papular skin rash, attributed to LTG. Headache, drowsiness, faintness, and diplopia, the common adverse events (AEs), were mild to moderate in intensity and occurred in 50–75% of patients in both groups (except for diplopia, occurring only with LTG). Concomitant AED plasma concentrations were not markedly changed by LTG. LTG pharmacokinetics were linear over the range of 500–700 mg/day. Conclusions: LTG doses 700 mg/day can be tolerated in patients receiving concomitant enzyme-inducing AEDs.     

Adverse effects of carbamazepine,phenytoin, valproate and lamotrigine monotherapy in epileptic adult Chinese patients

Objective

Antiepileptic drugs (AEDs) have been widely used in patients with epilepsy but the adverse effects in adult Chinese patients have not been investigated. This study evaluated the adverse effects of four commonly prescribed AED monotherapies with carbamazepine (CBZ), phenytoin (PHT), valproate (VPA), and lamotrigine (LTG) in adult Chinese patients with epilepsy.

Methods

The prospective open-label clinical trial was conducted at the Chongqing Epilepsy Center. The study enrolled 505 adults with newly diagnosed epilepsy, including generalized tonic–clonic (n = 110), partial and partial secondarily generalized (n = 395) seizures. Patients were evaluated by two clinicians at the Center and were prescribed one type of AED monotherapy with CBZ, PHT, VPA or LTG for a 24-month period. An adverse effect profile, as well as efficacy of monotherapy, was obtained through a face-to-face interview with the patient at each visit. A physical examination and routine laboratory tests were performed during a clinical screening.

Results

A total of 62.6% (316/505) patients successfully completed the AED monotherapy study: 64.3% of those receiving CBZ, 55.9%—PHT, 61.5%—VPA, and 66.2%—LTG. However, 34.7% of the patients discontinued the AED monotherapy because of unsatisfactory seizure control. Overall, 18% of patients experienced adverse effects: for CBZ (25/168; 14.9%), PHT (18/59; 30.5%), VPA (32/192; 16.7%) and LTG (16/86; 18.6%). The most common drug-related adverse events included gastrointestinal disturbances, loss of appetite and nausea, weight gain and fatigue/tiredness. Tremor and nystagmus occurred in some patients receiving PHT and VPA. Two CBZ, one PHT and four LTG patients (n = 7) discontinued the study due to rash.

Conclusion

Adult Chinese patients with epilepsy accepted and tolerated monotherapy with CBZ, PHT, VPA, and LTG. No fatal adverse events occurred. Unsatisfactory seizure control was a primary reason for withdrawal from the AED monotherapy study.     

An international multicenter randomized double-blind controlled trial of lamotrigine and sustained-release carbamazepine in the treatment of newly diagnosed epilepsy in the elderly

PURPOSE: To assess the comparative effectiveness, efficacy, and tolerability of lamotrigine (LTG) and sustained-release carbamazepine (CBZ) in the treatment of newly diagnosed epilepsy in the elderly. METHODS: Patients aged 65 years or older, who had experienced at least two unprovoked partial and/or generalized tonic-clonic seizures, were randomized to receive LTG (n=93) or CBZ (n=92) according to a multicenter double-blind, parallel-group design. Trial duration was 40 weeks and included a 4-week dose escalation followed by a maintenance phase during which dosages could be adjusted according to response. Initial, maintenance and maximum dosages were 25 mg, 100 mg, and 500 mg per day for LTG, and 100 mg, 400 mg, and 2,000 mg per day for CBZ, respectively. The primary end point was retention in the trial. RESULTS: In the LTG group, 68 patients (73%) completed the 40-week study period compared with 61 (67%) in the CBZ group, a nonsignificant difference. Time to withdrawal from any cause did not differ between groups (p=0.34). The number of subjects who completed the 40-week period and were seizure free in the last 20 weeks was 48 (52%) in the LTG group and 52 (57%) in the CBZ group. Adverse events leading to withdrawal occurred in 13 (14%) subjects in the LTG group and 23 (25%) subjects in the CBZ group. CONCLUSION: LTG and CBZ showed comparable effectiveness, with a trend for higher seizure-free rates for CBZ and better tolerability for LTG. Differences in outcome compared with previous trials may be related to different dosing rates and use of a sustained-release formulation for CBZ.     

Long-term efficacy of valproate versus lamotrigine in treatment of idiopathic generalized epilepsies in children and adolescents

PurposeIn order to estimate and compare the long-term effectiveness of lamotrigine (LTG) versus valproate (VPA) monotherapy in treatment of newly diagnosed idiopathic generalized epilepsies (IGE) the following study was performed.MethodsMedical records of 214 children and adolescents suffering from IGE were analyzed. 132 of them were on VPA monotherapy, 82 on LTG. The majority of patients had juvenile myoclonic epilepsy – 98, the rest: juvenile absence epilepsy – 32, childhood absence epilepsy – 53 and epilepsy with a tonic–clonic seizures on awakening – 12, others – 19. Mean age of the patients was 8.9 years (range 4–16 years). The mean time of treatment was 28 months, time of observation 40 months. In order to estimate retention rates and factors predicting successful treatment with LTG and VPA we used Kapplan–Meyer analysis and Gehan tests.ResultsData analysis showed significantly longer retention rates with VPA versus LTG treatment in overall rates as well in all syndromes subgroups. After 12 months of therapy 69% stayed on LTG therapy versus 89% on VPA, after 24 months 57% versus 83% respectively. VPA showed comparable efficacy in all IGE syndromes where LTG showed better efficacy in childhood and juvenile absence epilepsy than in juvenile myoclonic epilepsy. The shorter duration of treatment with LTG was due to lack of efficacy.ConclusionsOur results show the superiority of VPA versus LTG treatment in idiopathic generalized epilepsy syndromes.