Placebo-controlled trial of lamotrigine added to conventional and atypical antipsychotics in schizophrenia. Lamotrigine in treatment-resistant schizophrenia: a randomized placebo-controlled crossover trial. Neuropsychological assessment in lamotrigine treated epileptic patients. Lamotrigine versus placebo in the prophylaxis of migraine with and without aura. Adjunctive lamotrigine for partial seizures in patients aged 1 to 24 months. Lamotrigine (lamictal) in refractory trigeminal neuralgia: results from a double-blind placebo controlled crossover trial. Controlled trial of lamotrigine (Lamictal) for treatment-resistant partial seizures. Conjugated estrogens as adjuvant therapy in the treatment of acute schizophrenia: a double-blind study. Lamotrigine extended-release as adjunctive therapy for partial seizures.
Lamotrigine, a novel anticonvulsant drug having modulatory effects on glutamatergic neurotransmission, improves mood and cognition parameters in bipolar disorder. Recent studies suggest that when added to clozapine, lamotrigine treatment may result in significant positive symptoms reductions in schizophrenia. Similar effects were not observed in an open trial in which lamotrigine was used as adjuvant to nonclozapine antipsychotics.
                Thirty-eight treatment-resistant schizophrenia inpatients receiving conventional and atypical antipsychotics enrolled in a 10-week, double-blind, placebo-controlled study, in which they were randomized in a 2:1 ratio to receive adjuvant treatment with lamotrigine, gradually titrated to a 400 mg/day dose, or placebo. Of these, 31 completed the trial. Measures of clinical efficacy and side effects were determined every other week. Serum levels of amino acids were assessed at the beginning and end of the study.
                In primary last observation carried forward analysis, no statistically significant between-group differences were observed; however, the completers' analyses revealed that lamotrigine treatment resulted in significant (p < or = .05) reductions in positive and general psychopathology symptoms, as measured by the Positive and Negative Syndrome Scale. No significant differences in lamotrigine effects were noted between conventional versus atypical antipsychotics. Lamotrigine treatment was well tolerated, and glutamate serum levels remained stable throughout the study.
                These preliminary findings 1) support the hypothesis that lamotrigine adjuvant treatment may improve positive symptoms and general psychopathology in schizophrenia, 2) suggest that beneficial effects may be achieved when lamotrigine is added to both conventional and atypical antipsychotics, and 3) warrant additional, larger scale trials. There is no evidence from randomized, controlled trials that demonstrate effectiveness for any pharmacological treatment in clozapine-resistant schizophrenia. Since the introduction of chlorpromazine, all antipsychotics with proven efficacy on positive symptoms have been dopamine antagonists, but recent experimental data suggest that ketamine-induced positive schizophreniform symptoms in healthy subjects can be controlled by a glutamate antagonist lamotrigine. The hypothesis tested was that lamotrigine is more effective than placebo in the treatment of positive schizophrenic symptoms when combined with clozapine.
                Thirty-four hospitalized treatment-resistant patients having chronic schizophrenia participated in a double-blind, placebo-controlled, 14-week, crossover trial where 200 mg/day lamotrigine was gradually added to their ongoing clozapine treatment. Clinical assessments were made by the Positive and Negative Syndrome Scale at the beginning and end of each treatment period.
                In intention-to-treat analysis, lamotrigine treatment was more effective in reducing positive (effect size.7, p =.009) and general psychopathological (effect size.6, p =.030) symptoms, whereas no improvement was observed in negative symptoms.
                These results provide the first evidence from a randomized controlled trial of an effective pharmacological treatment with an anticonvulsant agent in treatment-resistant schizophrenia and indicate that both positive and general psychopathological symptoms in patients with schizophrenia can be controlled by a drug that is not a dopamine antagonist. The results are in line with previous experimental data suggesting that excessive glutamate neurotransmission contributes to the positive symptoms of schizophrenia. A double-blind, placebo controlled cross over study assessed the efficacy of lamotrigine as adjunct therapy for patients with refractory partial seizures. In addition to the main study, a neuropsychological component evaluated three main areas of cognitive function. These included: i) Concentration and attention; ii) General Cerebral Efficiency, and iii) Mnestic functions--immediate, short term and new learning ability. Ten subjects (4 males, 6 females, age range 22 to 53, mean age 31.3 years) were involved in the study, each assessed 3 times--baseline, end of phase I and end of phase II. Whilst statistical analysis proved impracticable due to differing scores across cells, between the results of lamotrigine and placebo, clinically, there appeared to be a marginal reduction in General Cerebral Efficiency during the lamotrigine phase. In the light of these tests, the conclusion is advanced that lamotrigine does not specifically impair cognitive function, and that it does not impair mnestic function. An alternate hypothesis of interaction effects is posited for the slight reduction in speed of information processing. Lamotrigine blocks voltage-sensitive sodium channels, leading to inhibition of neuronal release of glutamate. Release of glutamate may be essential in the propagation of spreading cortical depression, which some believe is central to the genesis of migraine attacks. This study compared safety and efficacy of lamotrigine and placebo in migraine prophylaxis in a double-blind randomized parallel-groups trial. A total of 110 patients entered; after a 1-month placebo run-in period, placebo-responders and non-compliers were excluded, leaving 77 to be treated with lamotrigine (n = 37) or placebo (n = 40) for up to 3 months. Initially, lamotrigine therapy was commenced at the full dose of 200 mg/day, but, following a high incidence of skin rashes, a slow dose-escalation was introduced: 25 mg/day for 2 weeks, 50 mg/day for 2 weeks, then 200 mg/day. Attack rates were reduced from baseline means of 3.6 per month on lamotrigine and 4.4 on placebo to 3.2 and 3.0 respectively during the last month of treatment. Improvements were greater on placebo and these changes, not statistically significant, indicate that lamotrigine is ineffective for migraine prophylaxis. There were more adverse events on lamotrigine than on placebo, most commonly rash. With slow dose-escalation their frequency was reduced and the rate of withdrawal for adverse events was similar in both treatment groups. This randomized, double-blind, placebo-controlled trial was conducted to assess the efficacy and tolerability of adjunctive lamotrigine for the treatment of partial seizures in infants aged 1 to 24 months.
                The study used a responder-enriched design in which all patients received adjunctive lamotrigine during an open-label phase (n = 177; maximum maintenance dose 5.1 mg/kg/day for those on non-enzyme-inducing antiepileptic drugs [AEDs] or valproate and 15.6 mg/kg/day for those on enzyme-inducing AEDs). Patients meeting response criteria were randomly assigned to double-blind treatment for up to 8 weeks with continued lamotrigine (n = 19) or to withdrawal from lamotrigine (placebo; n = 19) while background AEDs were maintained.
                The proportion of treatment failures (patients who met escape criteria or withdrew before completing the double-blind phase) was lower with lamotrigine (58%) than with placebo (84%). This finding was not significant in the primary analysis (two-sided chi(2) test [primary endpoint]). A post hoc sensitivity analysis of the primary endpoint was also performed (p = 0.045 by one-sided, mid-p corrected Fisher exact test). The median time to meet escape criteria was longer with lamotrigine (42 days) than with placebo (22 days) (p = 0.059). During the last 28 days of the open-label phase, 53% of the patients had a >or=50% reduction in frequency of partial seizures with lamotrigine. Additional reduction in partial seizure frequency was observed during the double-blind phase compared with the last 4 weeks of the open-label phase among those randomly assigned to lamotrigine (32% with a >or=25% reduction) but not those randomly assigned to placebo (5% with a >or=25% reduction). Lamotrigine was well tolerated, with an adverse event profile comparable to that observed in older pediatric patients.
                Lamotrigine was well tolerated, and the data indicate that it may be efficacious in the treatment of partial seizures in infants aged 1 to 24 months. Lamotrigine is a chemically novel antiepileptic drug which has not been adequately assessed for its antineuralgic properties. It was used in a double-blind placebo controlled crossover trial in 14 patients with refractory trigeminal neuralgia. Patients continued to take a steady dose of carbamazepine or phenytoin throughout the trial over a 31-day period. Each arm of the trial lasted 2 weeks with an intervening 3-day washout period. The maintenance dose of lamotrigine was 400 mg. Lamotrigine was superior to placebo (P = 0.011) based on analysis of a composite efficacy index which compared the numbers of patients assigned greater efficacy on lamotrigine with those assigned greater efficacy on placebo. Efficacy for one treatment over another was determined according to a hierarchy of: (i) use of escape medication; (ii) total pain scores; or (iii) global evaluations. Eleven of the 13 patients eligible for inclusion in the composite efficacy index showed better efficacy on lamotrigine compared with placebo. Global evaluations further suggested that patients did better on lamotrigine than placebo (P = 0.025). The adverse reactions with both lamotrigine and placebo were predominantly dose-dependent effects on the central nervous system. A 14th patient withdrew from the study due to severe pain during the placebo arm of the trial. It would appear that lamotrigine has antineuralgic properties. The antiepileptic effect of lamotrigine (Lamictal) was assessed in a double-blind, placebo-controlled, crossover trial in 56 adult patients with refractory partial seizures. Lamotrigine or placebo was added to the patients' existing antiepileptic drugs (AEDs). The dose of lamotrigine varied from 75 to 400 mg daily. Thirty-eight patients completed the trial and 7 withdrew because of adverse experiences. There was a statistically significant reduction in seizure counts on lamotrigine compared with placebo for total seizures (30.3% reduction, 95% CI 8.4%, 47.0%), complex partial seizures (29.2% reduction, 95% CI 3.8%, 47.9%) and secondary generalised seizures (37.9%, CI 18.9%, 52.4%). The analysis of total seizure days showed a similar significant reduction during lamotrigine treatment for the same seizure categories. There was no statistically significant difference in reporting of adverse events between lamotrigine and placebo except for dizziness which was reported more frequently on lamotrigine than on placebo. There were no differences in abnormal haematological or biochemical findings between lamotrigine and placebo, and lamotrigine had no effect on plasma concentrations of concomitant AEDs. In a double-blind, placebo controlled study, conjugated estrogens (CE) (0.625 mg/day) were added to a fixed dosage of haloperidol (5 mg daily). Forty-four female inpatients with acute schizophrenia were included in the study and randomized to one of the groups; 40 patients completed the trial. They were followed for 28 days and evaluated periodically with the BPRS, Negative Symptoms Rating Scale, Simpson Angus Extrapyramidal Rating Scale and UKU rating scale. Hormonal concentrations (estradiol, estrone, progesterone, FSH, LH and prolactine) were measured at baseline and weekly throughout the trial. Both groups showed similar clinical improvement during the evaluation, although there was a trend for the CE group to show a better improvement than the placebo group (p < 0.10). Side effects and the use of anticholinergics were similar in both groups. Conjugated estrogens caused elevation only of estrone levels in the CE group; estradiol and prolactin showed a similar profile for both groups. Our negative findings regarding the antipsychotic effect of conjugated estrogens does not preclude, however, a possible efficacy of other estrogens, such as 17-beta-estradiol, in schizophrenia. To evaluate the efficacy and tolerability of once-daily adjunctive lamotrigine extended-release (XR) for partial seizures in epilepsy.
                Patients more than 12 years old diagnosed with epilepsy with partial seizures and taking one to two baseline antiepileptic drugs were randomized to adjunctive once-daily lamotrigine XR or placebo in a double-blind, parallel-group trial. The study comprised a baseline phase, a 7-week double-blind escalation phase, and a 12-week double-blind maintenance phase during which doses of study medication and concomitant antiepileptic drugs were maintained.
                Of the 243 randomized patients, 239 (118 lamotrigine XR, 121 placebo) entered the escalation phase and received study medication. Lamotrigine XR was more effective than placebo with respect to median percent reduction from baseline in weekly partial seizure frequency (primary endpoint-entire 19-week treatment phase: 46.6% vs 24.5%, p = 0.0001 [corrected] via Wilcoxon test; escalation phase: 29.8% vs 15.6%, p = 0.027; maintenance phase: 58.4% vs 26.8%, p [corrected] < 0.0001). The percentage of patients with >or=50% reduction in partial seizure frequency (44.0% vs 20.8%, p = 0.0002) [corrected] and time to >or=50% reduction in partial seizure frequency (p = 0.0001) [corrected] also favored lamotrigine XR over placebo. A similar pattern of results was observed for secondarily generalized seizures. The most common adverse events were headache (lamotrigine XR 16%, placebo 18%) [corrected] and dizziness (lamotrigine XR 19%, [corrected] placebo 5%). Differences between lamotrigine XR and placebo on health outcomes measures were not significant.
                Once-daily adjunctive lamotrigine extended-release compared with placebo effectively reduced partial seizure frequency and was well tolerated in this double-blind study. Results support the clinical utility of this new once-daily formulation.
Evidence for use of lamotrigine as an adjuvant for people with schizophrenia is not robust and large well-designed, conducted and reported real-world randomised trials are needed to determine its place in everyday clinical practice.