8-Way Randomized Controlled Trial of Doxylamine, Pyridoxine and Dicyclomine for Nausea and Vomiting during Pregnancy: Restoration of Unpublished Information

The effects of pyridoxine (vitamin B6) supplementation in nausea and vomiting during pregnancy: a systematic review and meta-analysis

PURPOSE

Nausea and vomiting during pregnancy (NVP) are common symptoms in pregnancy. Although no definitive treatment option for NVP, pyridoxine (Vitamin B6) supplementation has been used widely. The present study aims to systematically evaluate the current evidence regarding pyridoxine for the treatment of NVP.

METHODS

Data were obtained using a stepwise search process using keywords in the following online medical databases; PubMed®, Web of Science®, and Scopus® for studies published before 1st May 2021. Studies reporting intervention with pyridoxine supplementation alone and/or with other active substances were included. A meta-analysis was performed on the PUQE score and Rhode's score for nausea and vomiting.

FINDINGS

Initial database searching indicated 548 potentially eligible articles, of which 18 studies satisfying the inclusion criteria were selected. Eight studies showed beneficial effects with pyridoxine alone as the supplementation, while six others found that the supplementation of pyridoxine in combination with another active substance had favourable effects. Supplementation of pyridoxine alone as well as combined treatment of pyridoxine with an active ingredient as the intervention significantly improved the symptoms of nausea according to Rhode's score [0.78 [95% CI: 0.26, 1.31; p = 0.003; I2 = 57%, p = 0.10)] and PUQE score [0.75 (95% CI: 0.28, 1.22; p = 0.002; I2 = 0%, p = 0.51)], respectively.

CONCLUSION

Supplementation of pyridoxine alone as well as with an active ingredient demonstrated beneficial effects for women suffering from NVP.

Bioavailability of Cariban® Capsules: A Modified-Release Fixed-Dose Combination of Doxylamine and Pyridoxine to Relieve Nausea and Vomiting During Pregnancy

BACKGROUND

Nausea and vomiting is a very prevalent condition during pregnancy. Combination of doxylamine and pyridoxine is placed as first-line pharmacological option for its treatment in most clinical guidelines. Among different release forms available, Cariban^® is a fixed-dose combination of doxylamine/pyridoxine 10/10 mg, formulated as modified-release capsules.

OBJECTIVES

In the present study, we aimed to characterize the bioavailability performance of Cariban^® in vitro and in vivo.

METHODS

An in vitro dissolution test was performed to evaluate the release profile of Cariban^®, together with immediate- and delayed-release formulations available on the market. A single-center, single-dose, open-label bioavailability study following Cariban^® administration in 12 healthy adult female patients was carried out to explore the drug behavior in vivo (protocol NBR-002-13; EUDRA-CT 2013-005422-35). These data were additionally used to perform a computational pharmacokinetic simulation of the posology approved for this drug.

RESULTS

Cariban^® capsules demonstrate a prolonged-release performance, with an early, gradual, and progressive release of both actives until reaching a complete dissolution after 4-5 h in solution. The pharmacokinetic features of these capsules show that doxylamine and pyridoxine metabolites are early absorbed, being all detectable in plasma within 1 h following oral administration. Computational pharmacokinetic simulation predicts that different posology provides distinct profiles of metabolites in plasma, with 1-1-2 (morning-midafternoon-night) being the one that concentrates higher plasma levels but lower dose dumping for 24 h.

CONCLUSION

Cariban^® behaves as a prolonged-release formulation, which correlates with rapid absorption and arising of the actives in the plasma, but also long-lasting and sustained bioavailability, especially when administered following the complete posology. These results would underlie its demonstrated efficacy to relieve nausea and vomiting of pregnancy (NVP) under clinical settings.

Irritable Bowel Syndrome in Pregnancy

Irritable bowel syndrome (IBS) affects a significant percentage of the general population and is more common in women. A large proportion of women affected with IBS are of childbearing age; however, there is a paucity of studies and guidelines to specifically address the epidemiology, course, maternal/fetal prognosis, or management of IBS in pregnancy. This scarcity of literature on IBS and pregnancy poses significant challenges to healthcare providers in counseling and managing patients. In this comprehensive review, we summarize the current literature and knowledge gaps regarding the effects of pregnancy on IBS and vice versa, along with the efficacy and safety profiles of commonly used IBS diets and medications in pregnancy. The management of pregnant women with IBS should be multidisciplinary, with emphasis on education and judicious use of dietary modifications and pharmacologic options that are deemed relatively safe during pregnancy.

Adjuvant-containing control arms in pivotal quadrivalent human papillomavirus vaccine trials: restoration of previously unpublished methodology

PURPOSE

Trustworthy reporting of quadrivalent human papillomavirus (HPV) vaccine trials is the foundation for assessing the vaccine's risks and benefits. However, several pivotal trial publications incompletely reported important methodological details and inaccurately described the formulation that the control arms received. Under the Restoring Invisible and Abandoned Trials initiative (RIAT), we aim to restore the public record regarding the content and rationale of the controls used in the trials.

METHODS

We assembled a cohort (five randomised controlled trials) described as placebo-controlled using clinical study reports (CSRs) obtained from the European Medicines Agency. We extracted the content and rationale for the choice of control used in each trial across six data sources: trial publications, register records, CSR synopses, CSR main bodies, protocols and informed consent forms.

RESULTS

Across data sources, the control was inconsistently reported as 'placebo'-containing aluminium adjuvant (sometimes with dose information). Amorphous aluminium hydroxyphosphate sulfate (AAHS) was not mentioned in any trial registry entry, but was mentioned in all publications and CSRs. In three of five trials, consent forms described the control as an 'inactive' substance. No rationale for the selection of the control was reported in any trial publication, register, consent form, CSR synopsis or protocol. Three trials reported the rationale for choice of control in CSRs: to preserve blinding and assess the safety of HPV virus-like particles as the 'safety profile of (AAHS) is well characterised'.

CONCLUSIONS

The stated rationale of using AAHS control-to characterise the safety of the HPV virus-like particles-lacks clinical relevance. A non-placebo control may have obscured an accurate assessment of safety and the participant consent process of some trials raises ethical concerns.

TRIAL REGISTRATION NUMBERS

NCT00092482, NCT00092521, NCT00092534, NCT00090220, NCT00090285.

New evidence for concern over the risk of birth defects from medications for nausea and vomitting of pregnancy

OBJECTIVES

The aim of the study was to quantify the risk of major congenital malformations (MCM) associated with first-trimester exposure to antiemetics.

STUDY DESIGN AND SETTING

Using the Quebec Pregnancy Cohort (1998-2015), first-trimester doxylamine-pyridoxine, metoclopramide, and ondansetron exposures were assessed for their association with MCM. Generalized estimating equations were used to estimate odds ratios (OR), adjusting for potential confounders (aOR).

RESULTS

Within 17 years of follow-up, the prevalence of antiemetic use during pregnancy increased by 76%. Within our cohort, 45,623 pregnancies were exposed to doxylamine-pyridoxine, 958 to metoclopramide, and 31 to ondansetron. Doxylamine-pyridoxine and metoclopramide use were associated with an increased risk of overall MCM (aOR 1.07, 95% confidence interval [CI]: 1.03-1.11; 3,945 exposed cases) and (aOR 1.27, 95% CI: 1.03-1.57; 105 exposed cases), respectively. Doxylamine-pyridoxine exposure was associated with increased risks of spina bifida (aOR 1.87, 95% CI: 1.11-3.14; 23 exposed cases), nervous system (aOR 1.25, 95% CI: 1.06-1.47; 225 exposed cases), and musculoskeletal system defects (aOR 1.08, 95% CI: 1.02-1.14; 1,735 exposed cases). Metoclopramide exposure was associated with an increased risk of genital organ defects (aOR 2.26, 95% CI: 1.14-4.48; 10 exposed cases). No statistically significant association was found between ondansetron exposure and the risk of overall MCM.

CONCLUSION

First-trimester doxylamine-pyridoxine and metoclopramide exposure was associated with a significantly increased risk of overall and specific MCM.

Research integrity and the law that never was

Evidence-based medicine is arguably among the most important innovations of the modern era, but publication bias and inadequate research transparency are serious issues affecting the very foundation of evidence-based practice. Despite this truth, these crucial issues have gone largely unaddressed or inadequately addressed for a distressingly long period of time. Regulatory efforts have thus far proven insufficient in eliminating these issues. Fortunately, the last 5 years in particular have seen developments that one hopes will contribute to the eradication of these issues and a future where we can look back on these issues as a sordid story of our past. However, much like the purported fixes of the past, time will be the final arbiter of the efficacy of remedial measures currently underway. This article chronicles the history of these issues, failed attempts to fix these issues, and what can be and is being done with the hope of bringing about true resolution.