The fair-haired giant. / Den blonde kjempe.

The much-loved fictional character of Jonas Fjeld is a heroic surgeon. But who was he modelled on? It may have been Dr. Tandberg at Lillehammer.

Efficacy, tolerability and pharmacokinetic variability of brivaracetam in adults with difficult-to-treat epilepsy.

PURPOSE: Brivaracetam (BRV) is one of our latest antiseizure medications (ASMs). It is an analogue of levetiracetam with limited real-life experience. The purpose of this study was to evaluate clinical experience with BRV with focus on efficacy, tolerability and pharmacokinetic variability among adult patients with difficult-to-treat epilepsy. METHODS: We retrospectively collected clinical and laboratory data from patients aged > 18 years who initiated treatment with BRV during 2016-2019 and were followed for > one year or cessation of BRV. RESULTS: The study cohort consisted of 120 adults with drug-resistant epilepsy. Serum concentrations of BRV were available in 72 patients. After one-year follow-up, the retention rate of BRV was 52%. Fifty-seven patients (48%) were responders (>50 reduction of seizure frequency), of whom six became seizure free. Adverse effects were reported in 78 patients (65%); 37 (31%) experienced psychiatric problems like increased irritability, anxiety and depressive symptoms. The mean daily BRV dose was 159 mg (SD 80 mg) and the mean serum concentration 5.4 µmol/L (SD 4.1 µmol/L). In 24 patients, BRV replaced levetiracetam. Pharmacokinetic variability between patients was considerable; 14-fold variation in concentration/dose (C/D)-ratios. Concomitant use of enzyme-inducing ASMs decreased the C/D-ratio by 48%. There were no significant differences in serum concentrations between responders vs. non-responders, or those who experienced adverse effects or not. CONCLUSION: After > 1 year of treatment with BRV, we found a responder rate of 48% in adult patients with difficult-to-treat epilepsy. The drug was largely well tolerated, but one third experienced psychiatric adverse effects. The combination of clinical and pharmacokinetic data provides insight into factors contributing to efficacy and tolerability of new ASMs.

Effect and tolerability of perampanel in patients with drug-resistant epilepsy.

OBJECTIVE: Perampanel is one of the most recently approved antiseizure medications. The aim of the present study was to assess clinical efficacy and tolerability, in combination with pharmacokinetic variability, of perampanel treatment in patients at a tertiary referral center for epilepsy. METHODS: We performed a retrospective observational study of patients given perampanel as adjunctive treatment in the period January 2013 - February 2019 at the National Center for Epilepsy at Oslo University Hospital, Norway. RESULTS: Clinical data were available for 175 mainly adult patients with drug-resistant epilepsy with mean treatment duration of 16.1 months. We found that 23% (40 patients) were responders (i.e., achieving more than 50% reduction in seizure frequency), four of whom became seizure free, 29% (51 patients) experienced a modest effect, whereas for 29% (50 patients) perampanel had no seizure-reducing effect. A paradoxical effect, with seizure aggravation, was reported in 9% (15 patients). The responder rate was significantly higher in those with slow vs. fast dosage titration. Logistic regression analysis showed better efficacy among those with generalized vs. those with focal epilepsy. Adverse effects were reported by 135 patients (77%), ranging from mild (34%), to moderate (41%) and severe (2%). In 55 patients (41%), these adverse effects resulted in discontinuation of treatment with perampanel. The most frequent adverse effects were psychiatric symptoms (34%), dizziness (31%), and sleepiness (26%). Of the 31 patients for whom serum concentration measurements were available, the mean daily perampanel dose was 6.3 mg (SD 3.0), with a mean serum concentration at steady state of 1.03 µmol/L (range: 0.15-3.59 µmol/L). There were pronounced differences between patients, as demonstrated by a 12-fold variability in the range of concentration/dose (C/D)-ratios (0.06 to 0.69 µmol/L/mg), where enzyme inducers contributed. CONCLUSION: Our results demonstrate that perampanel had a modest seizure-reducing effect in this very treatment-resistant patient group. Predictors of treatment success were generalized epilepsy and slow dosage titration. In patients without a history of psychiatric problems, clinicians could consider increasing dose of perampanel beyond 6 mg daily, taking co-medication and serum concentrations into account.

Clinical experience combined with therapeutic drug monitoring of lacosamide.

OBJECTIVE: Lacosamide (LCM) is an antiepileptic drug (AED) with insufficient clinical experience in patients with intellectual disability (ID). They often have more severe epilepsy with comorbidities. The objective was to evaluate the efficacy and tolerability of lacosamide (LCM) in patients with refractory epilepsy with and without ID in a real-life setting, taking drug monitoring (TDM) data into account therapeutic. METHODS: Retrospectively, we identified 344 patients using LCM from the TDM service covering the majority of the country, at the National Center for Epilepsy in Norway (2013-2018). Clinical and TDM data were available for 132 patients. RESULTS: Forty-four of the 132 patients (33%) had ID. The retention rate was significantly higher in the ID vs the non-ID group after 1 year (84% vs 68%, P < .05). By combining clinical and TDM data, we demonstrated that 37/38 responding patients had serum concentrations above the lower limit of the reference range (>10 µmol/L), and 16/17 with lower concentrations were non-responders. Mean serum concentration/dose ratios were similar in both groups, 0.06 and 0.07 µmol/L/mg. There were no significant differences regarding efficacy and tolerability. The risk of LCM withdrawal was significantly higher when LCM was added to sodium channel blockers, even if the latter was discontinued. SIGNIFICANCE: Lacosamide was generally well tolerated in patients with drug-resistant epilepsy, where one third had ID, and in these patients the retention rate was higher. The combination of clinical and TDM data could possibly facilitate LCM therapy in these vulnerable patients.

Sexual function in people with epilepsy: Similarities and differences with the general population.

OBJECTIVE: The potential impact of epilepsy on sexual function is important for patient welfare, but often neglected. This study explored the occurrences of different sexual problems in patients with both well-controlled and mostly refractory epilepsy, and compared these with equivalent information from the general population. METHODS: Between 2015 and 2017, a total of 221 adult inpatients and outpatients, mostly with intractable epilepsy, at the National Centre for Epilepsy in Norway, and 78 outpatients with well-controlled epilepsy at Lillehammer hospital participated in a questionnaire survey on sexual function. Information on the individual patient's epilepsy was collected. The results were compared with equivalent data on sexual function from 1671 adult Norwegians in the general population. RESULTS: Patients with epilepsy reported a significantly higher frequency of problems with orgasm, dyspareunia, erectile dysfunction, and feelings of sexual deviance. However, reduced sexual desire, premature ejaculation/climax, and vaginal dryness occurred at similar frequencies in the general population. After controlling for gender, we found no significant association between sexual problems and seizure control or use of enzyme-inducing antiepileptic drugs. In both genders, feelings of sexual deviance were associated with lower quality of life. Fewer patients with epilepsy were satisfied with their sex lives. The perception of sex as an important part of daily life was similar among women with epilepsy and women from the general population, whereas significantly fewer men with epilepsy than men in the general population reported that sex was an important part of their daily lives. Women with mostly refractory epilepsy reported asking for help with their sexual problems significantly more often than women in the other groups. SIGNIFICANCE: Some sexual problems occur significantly more often in patients with epilepsy than in the general population and feelings of sexual deviancy occur more frequently. No epilepsy-related factors could be identified as specific predictors.

Therapeutic Drug Monitoring of Lacosamide in Norway: Focus on Pharmacokinetic Variability, Efficacy and Tolerability.

Lacosamide (LCM) is a new antiepileptic drug (AED). Experience from therapeutic drug monitoring (TDM) in clinical practice is limited. The purpose of this study is to evaluate the pharmacokinetic variability of LCM in relation to efficacy and tolerability in patients with refractory epilepsy in a real-life setting. Variables included age, gender, daily doses and serum concentrations of LCM and other AEDs from the TDM-database at the National Center for Epilepsy in Norway. Clinical data regarding efficacy and tolerability were collected from medical records. The Norwegian Prescription Database (NorPD) was used to include population-based numbers of users. TDM-data from 344 patients were included. The median dose, serum concentration, and concentration/dose (C/D)-ratio of LCM was 350 (range 25-700) mg/day, 19.7 (range 8.1-56.2) µmol/L, and 0.06 (0.02-0.82) µmol/L/mg, respectively. Serum concentrations were reduced by 28% by concomitant use of enzyme inducers and increased by 30% in patients aged >65 years. Efficacy and tolerability were assessed in 227 patients: 29% had >50% seizure reduction (eight seizure free), 30% had no effect, and 44% reported adverse effects. In Norway, there were on average 500 patients per year using LCM in this period based on NorPD. The study demonstrated pharmacokinetic variability and use of TDM of LCM in Norway. Data were collected from multiple sources for improved pharmacovigilance. Serum concentrations were influenced by enzyme inducers and ageing, indicating the usefulness of TDM. Effect and tolerability were favorable within a suggested reference range of 10-40 µmol/L given drug-fasting conditions.

Pharmacokinetic variability, efficacy and tolerability of eslicarbazepine acetate-A national approach to the evaluation of therapeutic drug monitoring data and clinical outcome.

BACKGROUND: Eslicarbazepine acetate (ESL) is a new antiepileptic drug (AED), still insufficiently studied regarding pharmacokinetic variability, efficacy and tolerability. The purpose of this study was to evaluate therapeutic drug monitoring (TDM) data in Norway and relate pharmacokinetic variability to clinical efficacy and tolerability in a long-term clinical setting in patients with refractory epilepsy. METHODS: This retrospective observational study included TDM-data from the main laboratories and population data from the Norwegian Prescription Database in Norway, in addition to clinical data from medical records of adult patients using ESL for up to three years, whenever possible. RESULTS: TDM-data from 168 patients were utilized for assessment of pharmacokinetic variability, consisting of 71% of the total number of patients in Norway using ESL, 2011-14. Median daily dose of ESL was 800mg (range 400-1600mg), and median serum concentration of ESL was 53µmol/L (range 13-132µmol/L). Inter-patient variability of ESL was extensive, with 25-fold variability in concentration/dose ratios. Additional clinical data were available from 104 adult patients out of the 168, all with drug resistant focal epilepsy. After 1, 2 and 3 years follow-up, the retention rate of ESL was 83%, 72% and 64%, respectively. ESL was generally well tolerated as add-on treatment, but sedation, cognitive impairment and hyponatremia were reported. Hyponatremia (sodium <137mmol/L) was present in 36% of the patients, and lead to discontinuation in three. CONCLUSION: Pharmacokinetic variability of ESL was extensive and the demonstration of usefulness of TDM requires further studies. In patients with drug resistant focal Epilepsy, the high retention rate indicated good efficacy and tolerability. Hyponatremia was observed in one third of the patients. The present results point to a need for individualization of treatment and TDM may be useful.

The Impact of Pharmacokinetic Interactions With Eslicarbazepine Acetate Versus Oxcarbazepine and Carbamazepine in Clinical Practice.

BACKGROUND: Eslicarbazepine acetate (ESL) is a new anti-epileptic drug (AED) chemically related to oxcarbazepine (OXC) and carbamazepine (CBZ) and is increasingly used in clinical practice. The purpose of the study was to investigate 2-way pharmacokinetic interactions between ESL and other AEDs as compared to OXC and CBZ. METHODS: Anonymous data regarding age, gender, use of AEDs, daily doses and serum concentration measurements of ESL, OXC, CBZ and lamotrigine (LTG) and other AEDs were retrieved from 2 therapeutic drug monitoring (TDM) databases in Norway. Drugs were categorized according to their known potential for interactions. Concentration/dose (C/D) ratios were calculated. RESULTS: Data from 1100 patients were available. The C/D ratios of ESL and OXC were unchanged in combination with enzyme-inducing AEDs or valproate (VPA). The C/D ratio of CBZ decreased by 40% and 22% in combination with other enzyme-inducing AEDs or VPA, respectively, pointing to an increased clearance. ESL demonstrated no significant enzyme-inducing effect on LTG metabolism although there was a 20% and 34% decrease in the C/D ratio of LTG in combination with OXC and CBZ, respectively. CONCLUSIONS: Possible pharmacokinetic interactions have been studied for ESL as compared to OXC and CBZ. The pharmacokinetics of ESL is not affected by enzyme-inducing AEDs or VPA and does not affect the metabolism of LTG in contrast to OXC and CBZ. The study demonstrates the value of using TDM databases to explore the potential for pharmacokinetic interactions of new AEDs.

[Long-term adverse effects of anti-epileptic drugs]. / Langtidsbivirkninger av antiepileptika.

Around 120,000 patients in Norway use anti-epileptic drugs daily. Their use has increased in recent years, partly because these drugs are also used for psychiatric disorders, migraine and neuropathic pain. Treatment usually lasts for many years. It is important for doctors to familiarise themselves with the adverse effect profile of these drugs, especially because the long-term adverse effects are generally insidious and are easy for both doctor and patient to overlook.

[Antiepileptic drugs and congenital malformations]. / Antiepileptika og medfødte misdannelser.

BACKGROUND: In pregnant women with epilepsy the use of antiepileptic drugs may increase the risk of harming the foetus. For the treating neurologist it may be challenging to find a balance between optimal seizure control and the lowest possible drug dosage. The aim of this study was to assess the prevalence and type of congenital malformations in children exposed to antiepileptic drugs during pregnancy. MATERIAL AND METHOD: In Norway we have prospectively followed 813 pregnancies in women with epilepsy as part of an international cohort study. The women had three check-ups during the pregnancy, and the children were followed up twice during their first year of life. RESULTS: We found a total of 34 congenital malformations in the children, of which 12 were heart defects, yielding a malformation rate of 4.5%. Six of the malformations (18%) were detected prenatally, 20 (59%) were reported immediately after birth, and eight (24%) were discovered during the child's first year of life. INTERPRETATION: Our study shows that 95.5%.of the women included who used antiepileptic drugs during pregnancy gave birth to a healthy child. This Norwegian cohort is too small to evaluate the teratogenic risk associated with the individual drugs.