The analgesic effect and adverse events of the weak opioid codeine is assumed to be mediated by its metabolite morphine. The cytochrome P-450 enzyme CYP2D6 catalysing the formation of morphine exhibits a genetic polymorphism. Two distinct phenotypes, the extensive (EMs) and poor metabolisers (PMs), are present in the population. The prevalence of PMs in the Caucasian population is 7% to 10%. Since PMs do not express functional CYP2D6, they have a severely impaired capacity to metabolise drugs which are substrates of this enzyme. Provided the analgesic effect and the adverse events of codeine are mediated by its metabolite morphine, large phenotype-related differences are to be expected and PMs, as they form only trace amounts of morphine, can serve as a model to test the hypothesis whether the analgesia and adverse events of codeine are mediated by the parent drug or its metabolite morphine. Therefore we have studied in a randomised placebo-controlled double-blind trial the analgesic effect of 170 mg codeine (p.o.) compared to 20 mg morphine (p.o.) and placebo in 9 EMs and 9 PMs using the cold pressor test. The duration and intensity of the side effects were assessed using visual analogue scales (VAS). Codeine and morphine concentrations were measured in serum and urine. Compared to placebo, 20 mg morphine caused a significant increase in pain tolerance in both phenotypes, EMs and PMs (16.2+/-27.4 vs. -0.66+/-27.4 s x h, n=18). However, following administration of codeine, analgesia was only observed in EMs but not in PMs (EMs: 54.9+/-42.2 vs. 1.7+/-4.2 s x h, P < 0.01; PMs: 9.6+/-10.9 vs. 3.3+/-23.7 s x h, not significant). Adverse events were significantly more pronounced after morphine and codeine compared to placebo in both EMs and PMs. In contrast to the phenotype-related differences in the analgesic effect of codeine, however, no difference in adverse events between the phenotypes could be observed. In the pharmacokinetic studies, significant differences between the two phenotypes in the formation of morphine after codeine administration could be observed. Whereas morphine plasma concentrations were similar in PMs (Cmax: 44+/-13 nmol/l: AUC: 199+/-45 nmol x h/l) and EMs (Cmax: 48+/-17 nmol/l); AUC: 210+/-65 nmol x h/l) after morphine administration, following 170 mg codeine, morphine plasma concentrations comparable to those after morphine application were only observed in EMs (Cmax: 38+/-16 nmol/l; AUC: 173+/-90 nmol x h/l). In PMs only traces of morphine could be detected in plasma (Cmax: 2+/-1 nmol/l; AUC: 10+/-7 nmol x h/l). The percentage of the codeine dose converted to morphine and its metabolites was 3.9% in EMs and 0.17% in PMs. The interindividual variability in analgesia of codeine which is related to genetically determined differences in the formation of morphine clearly indicate that this metabolite is responsible for the analgesic effect of codeine. In contrast to the analgesic effect, frequency and intensity of the adverse events did not present significant differences between the two phenoty...
Objective:To assess the efficacy, safety, and tolerability of adjunctive brivaracetam (BRV), a selective, high-affinity ligand for SV2A, for treatment of partial-onset (focal) seizures (POS) in adults.Methods:Data were pooled from patients (aged 16–80 years) with POS uncontrolled by 1 to 2 antiepileptic drugs receiving BRV 50, 100, or 200 mg/d or placebo, without titration, in 3 phase III studies of BRV (NCT00490035, NCT00464269, and NCT01261325, ClinicalTrials.gov, funded by UCB Pharma). The studies had an 8-week baseline and a 12-week treatment period. Patients receiving concomitant levetiracetam were excluded from the efficacy pool.Results:In the efficacy population (n = 1,160), reduction over placebo (95% confidence interval) in baseline-adjusted POS frequency/28 days was 19.5% (8.0%–29.6%) for 50 mg/d (p = 0.0015), 24.4% (16.8%–31.2%) for 100 mg/d (p < 0.00001), and 24.0% (15.3%–31.8%) for 200 mg/d (p < 0.00001). The ≥50% responder rate was 34.2% (50 mg/d, p = 0.0015), 39.5% (100 mg/d, p < 0.00001), and 37.8% (200 mg/d, p = 0.00003) vs 20.3% for placebo (p < 0.01). Across the safety population groups (n = 1,262), 90.0% to 93.9% completed the studies. Treatment-emergent adverse events (TEAEs) were reported by 68.0% BRV overall (n = 803) and 62.1% placebo (n = 459). Serious TEAEs were reported by 3.0% (BRV) and 2.8% (placebo); 3 patients receiving BRV and one patient receiving placebo died. TEAEs in ≥5% patients taking BRV (vs placebo) were somnolence (15.2% vs 8.5%), dizziness (11.2% vs 7.2%), headache (9.6% vs 10.2%), and fatigue (8.7% vs 3.7%).Conclusions:Adjunctive BRV was effective and generally well tolerated in adults with POS.Classification of evidence:This analysis provides Class I evidence that adjunctive BRV is effective in reducing POS frequency in adults with epilepsy and uncontrolled seizures.
We evaluated nonpsychotic behavioral adverse events (BAEs) in patients receiving levetiracetam (LEV) who switched to brivaracetam (BRV). Patients ≥16 years of age, receiving 2-3 antiepileptic drugs (AEDs), including LEV 1-3g/day, and experiencing BAEs within 16 weeks of LEV treatment initiation, enrolled in an open-label Phase 3b study (NCT01653262) comprising a ≤1-week screening period, an immediate switch from LEV to BRV 200mg/day (without titration), and a 12-week treatment period. The percentages of patients with investigator-assessed clinically meaningful reduction in BAEs, shift in maximum BAE intensity, and change in health-related quality of life (HRQoL) (Patient-Weighted Quality of Life in Epilepsy Inventory-Form 31 [QOLIE-31-P]) were assessed. Of 29 patients enrolled, 26 (89.7%) completed the study. At the end of the treatment period, 27/29 (93.1%) patients switched to BRV had clinically meaningful reductions in BAEs. Physicians reported a reduction in the maximum intensity of primary BAEs in 27/29 (93.1%) patients. Mean change from baseline to Week 12 in QOLIE-31-P total score was 12.1, indicating improved HRQoL. During the treatment period, 23/29 (79.3%) patients reported treatment-emergent adverse events (TEAEs). One patient reported a serious TEAE (suicidal ideation and suicide attempt). Two patients discontinued BRV because of TEAEs. Findings from this small study suggest that patients experiencing BAEs associated with LEV may benefit from switching to BRV.
SUMMARYObjectives: To report pooled safety/tolerability and seizure outcome data from adults with uncontrolled partial-onset (focal) seizures (POS) receiving adjunctive brivaracetam (BRV) during phase IIb/III and long-term follow-up (LTFU) studies. Methods: Seizure outcome data were pooled from phase IIb (NCT00175929 and NCT00175825), III/IIIb (NCT00490035, NCT00464269, NCT00504881, and NCT01261325) and associated LTFU studies (NCT00175916, NCT00150800, and NCT01339559). Safety/tolerability data were pooled from these studies plus NCT01405508, NCT01653262, and NCT01728077 (LTFU). Patients received placebo (during core studies) or BRV 5-200 mg/day. Safety/tolerability and seizure outcomes (BRV modal doses 50-200 mg/day) were assessed until January 17, 2014. Results: Of 2,186 patients (97.3% with POS and 2.7% with other seizure types) who received BRV 50-200 mg/day, 2,051 (93.8%) completed core studies and continued in LTFU studies. Total BRV exposure: 5,339.4 patient-years (≥8.0 years in 41 patients); 6-, 12-, 24-, and 60-month retention: 91.0%, 79.8%, 68.1%, and 54.4%, respectively. Safety/tolerability data pooled from 2,186 patients: ≥1 treatmentemergent adverse event (TEAE) reported by 1,848 (84.5%) patients; 1,184 (54.2%) reported ≥1 TEAE considered treatment-related. Most frequent TEAEs (≥10%): headache (20.9%), dizziness (17.5%), somnolence (15.2%), nasopharyngitis (13.2%), fatigue (11.3%), and convulsion (10.6%). Serious TEAEs (SAEs) and treatmentrelated SAEs: 401 (18.3%) and 95 (4.3%) patients, respectively. Of 28 (1.3%) deaths, four (14.3%) were considered possibly treatment related by the investigator. Pooled seizure outcome data (1,836 patients): median POS frequency/28 days at baseline was 8.9; on treatment, median percentage reduction from baseline in POS/28 days was 48.8%, and ≥50% responder rate was 48.7%. Complete seizure freedom: 4.9%, 4.2%, 3.0%, and 3.3% for ≥6, 12, 24, and 60 months, respectively. Improvements were seen in health-related quality of life (HRQoL) from baseline, assessed by Quality of Life in Epilepsy Inventory-31. Significance: Adjunctive BRV treatment in adults with POS was effective and generally well tolerated when administered long-term (≥8.0 years). Retention was high and HRQoL improvements were observed.
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