Validating the effect of Ondansetron and Mirtazapine In Treating hyperemesis gravidarum (VOMIT): protocol for a randomised placebo-controlled trial

Anti-emetic effects of thalidomide: Evidence, mechanism of action, and future directions

The rationale for using thalidomide (THD) as a treatment for nausea and vomiting during pregnancy in the late 1950s appears to have been based on its sedative or hypnotic properties. In contrast to contemporaneous studies on the anti-emetic activity of phenothiazines, we were unable to identify publications reporting preclinical or clinical evaluation of THD as an anti-emetic. Our survey of the literature revealed a clinical study in 1965 showing THD reduced vomiting in cancer chemotherapy which was substantiated by similar studies from 2000, particularly showing efficacy in the delayed phase of chemotherapy-induced nausea and vomiting. To identify the mechanism(s) potentially involved in thalidomide's anti-emetic activity we reviewed its pharmacology in the light of nausea and vomiting mechanisms and their pharmacology with a particular emphasis on chemotherapy and pregnancy. The process identified the following potential mechanisms: reduced secretion of Growth Differentiation Factor 15, suppression of inflammation/prostaglandin production, downregulation of cytotoxic drug induced upregulation of iNOS, and modulation of BK (KCa1.1) channels and GABAA/glutamate transmission at critical points in the emetic pathways (nucleus tractus solitarius, area postrema). We propose ways to investigate these hypothesized mechanisms and discuss the associated challenges (e.g., objective quantification of nausea) in addition to some of the more general aspects of developing novel drugs to treat nausea and vomiting.

Systematic evidence map of evidence addressing the top 10 priority research questions for hyperemesis gravidarum

OBJECTIVE

Knowledge gaps regarding hyperemesis gravidarum (HG) are substantial. We aimed to systematically identify and map recent evidence addressing the top 10 priority questions for HG, as published in 2021 in a James Lind Alliance Priority Setting Partnership.

DESIGN

Systematic evidence map.

METHODS

We searched MEDLINE and EMBASE on 12 January 2021 and CINAHL on 22 February 2021 with search terms hyperemesis gravidarum, pernicious vomiting in pregnancy and their synonyms. Results were limited to 2009 onwards. Two reviewers independently screened titles and abstracts to assess whether the studies addressed a top 10 priority questions for HG. Differences were discussed until consensus was reached. Publications were allocated to one or more top 10 research questions. Study design was noted, as was patient or public involvement. Two reviewers extracted data synchronously and both cross-checked 10%. Extracted data were imported into EPPI-Reviewer software to create an evidence map.

OUTCOME MEASURES

The number and design of studies in the search yield, displayed per the published 10 priority questions.

RESULTS

Searches returned 4338 results for screening; 406 publications were included in the evidence map. 136 publications addressed multiple questions. Numerous studies address the immediate and long-term outcomes or possible markers for HG (question 8 and 9, respectively 164 and 82 studies). Very few studies seek a possible cure for HG (question 1, 8 studies), preventative treatment (question 4, 2 studies) or how to achieve nutritional requirements of pregnancy (question 10, 17 studies). Case reports/series were most numerous with 125 (30.7%) included. Few qualitative studies (9, 2.2%) were identified. 25 (6.1%) systematic reviews addressed eight questions, or aspects of them. 31 (7.6%) studies included patient involvement.

CONCLUSIONS

There are significant gaps and overlap in the current HG literature addressing priority questions. Researchers and funders should direct their efforts at addressing the gaps in the top 10 questions.

Mirtazapine exposure in pregnancy and fetal safety: A nationwide cohort study

OBJECTIVE

To investigate the association between mirtazapine exposure in pregnancy and risk of specific adverse pregnancy outcomes.

METHODS

A register-based nationwide cohort study was conducted including all registered pregnancies in Denmark from 1997 to 2016. Mirtazapine-exposed pregnancies were compared with mirtazapine unexposed pregnancies in a 1:4 ratio matched according to propensity scores. Outcomes were major congenital malformations analyzed using log binomial models, and spontaneous abortion, stillbirth and neonatal death analyzed using Cox proportional hazard regression.

RESULTS

From a source population of 1,650,649 pregnancies, the propensity score-matched cohort included 4475 pregnancies (895 mirtazapine exposed) in the analysis of major congenital malformations. The analyses of spontaneous abortion included 9 500 pregnancies (1900 mirtazapine exposed), and for the analyses of stillbirths and neonatal deaths 9725 (1 945 mirtazapine-exposed) and 4485 pregnancies (897 mirtazapine-exposed) were included, respectively. Thirty-one (3.5%) children were diagnosed with major congenital malformation among the mirtazapine exposed compared with 152 (4.3%) among the unexposed pregnancies (OR=0.81, 95% CI 0.55-1.20). Spontaneous abortion occurred in 237 (12.5%) of the mirtazapine exposed compared with 931 (12.3%) of the unexposed pregnancies (HR = 1.04%, 95% CI 0.91-1.20). The analyses revealed no increased risk of stillbirth (HR = 0.88%, 95% CI 0.34-2.29) or neonatal death (HR = 0.60%, 95% CI 0.18-2.02).

CONCLUSIONS

In this nationwide Danish register study, mirtazapine exposure in pregnancy was not associated with major congenital malformations, spontaneous abortion, stillbirth, or neonatal death. Clinicians and patients can be reassured that mirtazapine is safe in pregnancy.