Detecting the toxic effects of chemicals on reproduction and development without using mammalian animal models is crucial in the exploitation of pharmaceuticals for human use. Zebrafish are a promising animal model for investigating pharmacological effects and toxicity during vertebrate development. Several studies have suggested the use of zebrafish embryos for the assessment of malformations or embryo-fetal lethality (MEFL). However, a reproducible protocol as a standard for the zebrafish MEFL test method that fulfills global requests has not been established based on the International Council of Harmonisation (ICH) S5 (R3) guidelines. To establish such a toxicity test method, we developed a new and easy protocol to detect MEFL caused by chemicals, especially those with teratogenic potential, using fertilized zebrafish eggs (embryos) within 5 days of development. Our toxicity test trials using the same protocol in two to four different laboratories corroborated the high inter-laboratory reproducibility. Our test method enabled the detection of 18 out of 22 test compounds that induced rat MEFL. Thus, the prediction rate of our zebrafish test method for MEFL was almost 82% compared with that of rat MEFL. Collectively, our study proposes the establishment of an easy and reproducible protocol for the zebrafish MEFL test method for reproductive and developmental toxicity that meets ICH guideline S5 (R3), which can be further considered in combination with information from other sources for regulatory use.

Valproate (VPA) is an effective treatment for epilepsy and also used in bipolar disorder. However, VPA is associated with a significant risk of birth defects and developmental disorders if used during pregnancy. This has led to the introduction of measures to reduce the use of valproate in women of childbearing potential such as the \'Prevent\' pregnancy prevention program (PPP) and the completion of an annual risk acknowledgement form (ARAF). The aim of the current audit was to assess compliance with the guidance. An audit tool was made available to neurologists registered with the Association of British Neurologists (ABN) and to epilepsy nurse specialists via the Epilepsy Nurses Association (ESNA) in the UK. Data were collected between November 2020 and March 2021. The main indication for valproate was generalised epilepsy (55.8%), followed by focal (22.5%). For most, there was documentation that the woman had been informed about the risks associated with taking valproate during pregnancy (93.1%) and the need to be on highly effective contraception or that this was not deemed appropriate (92.2%). A signed ARAF was available in the notes for 81.2% although only 66% were <12 months old. Although information had been made available for most women, there were still individuals where this was not documented. Further work is needed to facilitate identification of women taking valproate and implementation of a digital ARAF. For clinicians, the audit highlights a need to carefully counsel women about the teratogenic risks of continuing to take valproate versus the risk of deteriorating seizure control if the drug is withdrawn. This is particularly true of women with focal epilepsy, where there may be safer, equally effective, alternative anti-seizure medication (ASM). The aim should be to create a partnership of trust between the patient and clinician in order to arrive at the best clinical decision for that individual.

The zebrafish as an alternative animal model for developmental toxicity testing has been extensively investigated, but its assay protocol was not harmonized yet. This study has validated and optimized the zebrafish developmental toxicity assay previously reported by multiple inter-laboratory studies in the United States and Europe. In this study, using this classical protocol, of 31 ICH-positive compounds, 23 compounds (74.2%) were teratogenic in zebrafish, five had false-negative results, and three were neither teratogenic nor non-teratogenic according to the protocol standard; of 14 ICH-negative compounds, 12 compounds (85.7%) were non-teratogenic in zebrafish and two had false-positive results. After we added an additional TI value in the zebrafish treated with testing compounds at 2 dpf along with the original 5 dpf, proposed a new category as the uncategorized compounds for those TI values smaller than the cutoff both at 2 dpf and 5 dpf but inducing toxic phenotypes, refined the testing concentration ranges, and optimized the TI cut-off value from ≥ 10 to ≥ 3 for compounds with refined testing concentrations, this optimized zebrafish developmental assay reached 90.3% sensitivity (28/31 positive compounds were teratogenic in zebrafish) and 88.9% (40/45) overall predictability. Our results from this study strongly support the use of zebrafish as an alternative in vivo method for screening and assessing the teratogenicity of candidate drugs for regulatory acceptance.

Decisions about the use of psychotropic medication in pregnancy are an ongoing challenge for clinicians and women with mental health problems, owing to the uncertainties around risks of the illness itself to mother and fetus/infant, effectiveness of medications in pregnancy and risks to the fetus/infant from in utero exposure or via breast milk. These consensus guidelines aim to provide pragmatic advice regarding these issues. They are divided into sections on risks of untreated illness in pregnancy; general principles of using drugs in the perinatal period; benefits and harms associated with individual drugs; and recommendations for the management of specific disorders.

SWOT analysis was used to gain insights and perspectives into the revision of the ICH S5(R2) guideline on detection of toxicity to reproduction for medicinal products. The current ICH guideline was rapidly adopted worldwide and has an excellent safety record for more than 20 years. The revised guideline should aim to further improve reproductive and developmental (DART) safety testing for new drugs. Alternative methods to animal experiments should be used whenever possible. Modern technology should be used to obtain high quality data from fewer animals. Additions to the guideline should include considerations on the following: limit dose setting, maternal toxicity, biopharmaceuticals, vaccines, testing strategies by indication, developmental immunotoxicity, and male-mediated developmental toxicity. Emerging issues, such as epigenetics and the microbiome, will most likely pose challenges to DART testing in the future. It is hoped that the new guideline will be adopted even outside the ICH regions.

In the last couple of years, the interest in the zebrafish embryotoxicity test (ZET) for use in developmental toxicity assessment has been growing exponentially. This is also evident from the recent proposal for updating the ICHS5 guideline. The methodology of the ZET used by the different groups varies greatly. To further evaluate its successfulness and to take the ZET to the next level, harmonization of procedures is crucial. In the present study, based on literature and empirical data, the most optimal study design regarding temperature, test chamber, exposure period, presence of chorion, solvent use, exposure method, choice of concentrations, and teratogenic classification is proposed. Furthermore, our morphology scoring system is reported in detail as protocol to further enhance study design harmonization.

BACKGROUND: The characteristics of some population groups (patients with comorbidities, women of childbearing age, the elderly) may limit epilepsy management. Antiepileptic treatment in these patients may require adjustments.
METHODS: We searched articles in Pubmed, clinical practice guidelines for epilepsy, and recommendations by the most relevant medical societies regarding epilepsy in special situations (patients with comorbidities, women of childbearing age, the elderly). Evidence and recommendations are classified according to the prognostic criteria of Oxford Centre of Evidence-Based Medicine (2001) and the European Federation of Neurological Societies (2004) for therapeutic interventions.
CONCLUSIONS: Epilepsy treatment in special cases of comorbidities must be selected properly to improve efficacy with the fewest side effects. Adjusting antiepileptic medication and/or hormone therapy is necessary for proper seizure management in catamenial epilepsy. Exposure to antiepileptic drugs (AED) during pregnancy increases the risk of birth defects and may affect fetal growth and/or cognitive development. Postpartum breastfeeding is recommended, with monitoring for adverse effects if sedative AEDs are used. Finally, the elderly are prone to epilepsy, and diagnostic and treatment characteristics in this group differ from those of other age groups. Although therapeutic limitations may be more frequent in older patients due to comorbidities, they usually respond better to lower doses of AEDs than do other age groups.