Pharmacogenetic aspects of the use of oral contraceptives and the risk of thrombosis

Stroke in SARS-CoV-2 Infection: A Pictorial Overview of the Pathoetiology

Since the early days of the pandemic, there have been several reports of cerebrovascular complications during the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Numerous studies proposed a role for SARS-CoV-2 in igniting stroke. In this review, we focused on the pathoetiology of stroke among the infected patients. We pictured the results of the SARS-CoV-2 invasion to the central nervous system (CNS) via neuronal and hematogenous routes, in addition to viral infection in peripheral tissues with extensive crosstalk with the CNS. SARS-CoV-2 infection results in pro-inflammatory cytokine and chemokine release and activation of the immune system, COVID-19-associated coagulopathy, endotheliitis and vasculitis, hypoxia, imbalance in the renin-angiotensin system, and cardiovascular complications that all may lead to the incidence of stroke. Critically ill patients, those with pre-existing comorbidities and patients taking certain medications, such as drugs with elevated risk for arrhythmia or thrombophilia, are more susceptible to a stroke after SARS-CoV-2 infection. By providing a pictorial narrative review, we illustrated these associations in detail to broaden the scope of our understanding of stroke in SARS-CoV-2-infected patients. We also discussed the role of antiplatelets and anticoagulants for stroke prevention and the need for a personalized approach among patients with SARS-CoV-2 infection.

Drug-Induced Thrombosis—Experimental, Clinical, and Mechanistic Considerations

Awareness of the dangers of drug-induced thrombosis has recently been heightened and led to demand for improved testing methodology. For example, reports indicating that some selective inhibitors of cyclooxygenase-2 (COX-2) increase the risk of myocardial infarction and atherothrombotic events caused the withdrawal of rofecoxib from global markets and the issuance of warnings concerning the usage of other COX-2 inhibitors. Drugs may exert a prothrombotic state by a variety of mechanisms–those affecting the vessel wall, the blood flow, and/or different blood constituents. Our review serves as an update to that of Gerhard Zbinden published in 1976 by presenting recently acquired data that more fully elucidate the different mechanisms by which drugs are believed to induce thrombogenic effects and discussing new methods used to detect these without losing sight of the classical pathology of thrombosis. We offer correlations between experimental findings and clinical data and conclude that, because drugs may induce a prothrombotic state by a variety of mechanisms, they should be tested for these using appropriate experimental methods and animal models.

Combined oral contraceptives: venous thrombosis

BACKGROUND

Combined oral contraceptive (COC) use has been associated with venous thrombosis (VT) (i.e., deep venous thrombosis and pulmonary embolism). The VT risk has been evaluated for many estrogen doses and progestagen types contained in COC but no comprehensive comparison involving commonly used COC is available.

OBJECTIVES

To provide a comprehensive overview of the risk of venous thrombosis in women using different combined oral contraceptives.

SEARCH METHODS

Electronic databases (Pubmed, Embase, Web of Science, Cochrane, CINAHL, Academic Search Premier and ScienceDirect) were searched in 22 April 2013 for eligible studies, without language restrictions.

SELECTION CRITERIA

We selected studies including healthy women taking COC with VT as outcome.

DATA COLLECTION AND ANALYSIS

The primary outcome of interest was a fatal or non-fatal first event of venous thrombosis with the main focus on deep venous thrombosis or pulmonary embolism. Publications with at least 10 events in total were eligible. The network meta-analysis was performed using an extension of frequentist random effects models for mixed multiple treatment comparisons. Unadjusted relative risks with 95% confidence intervals were reported.Two independent reviewers extracted data from selected studies.

MAIN RESULTS

3110 publications were retrieved through a search strategy; 25 publications reporting on 26 studies were included. Incidence of venous thrombosis in non-users from two included cohorts was 0.19 and 0.37 per 1 000 person years, in line with previously reported incidences of 0,16 per 1 000 person years. Use of combined oral contraceptives increased the risk of venous thrombosis compared with non-use (relative risk 3.5, 95% confidence interval 2.9 to 4.3). The relative risk of venous thrombosis for combined oral contraceptives with 30-35 μg ethinylestradiol and gestodene, desogestrel, cyproterone acetate, or drospirenone were similar and about 50-80% higher than for combined oral contraceptives with levonorgestrel. A dose related effect of ethinylestradiol was observed for gestodene, desogestrel, and levonorgestrel, with higher doses being associated with higher thrombosis risk.

AUTHORS' CONCLUSIONS

All combined oral contraceptives investigated in this analysis were associated with an increased risk of venous thrombosis. The effect size depended both on the progestogen used and the dose of ethinylestradiol. Risk of venous thrombosis for combined oral contraceptives with 30-35 μg ethinylestradiol and gestodene, desogestrel, cyproterone acetate and drospirenone were similar, and about 50-80% higher than with levonorgestrel. The combined oral contraceptive with the lowest possible dose of ethinylestradiol and good compliance should be prescribed-that is, 30 μg ethinylestradiol with levonorgestrel.

Estrogen abolishes latent inhibition in ovariectomized female rats

Estrogen is frequently prescribed as a method of birth control and as hormone replacement therapy for post-menopausal women with varied effects on cognition. Here the effects of estrogen on attention were examined using the latent inhibition (LI) behavioral paradigm. Ovariectomized (OVX) female rats were given either estrogen benzoate (EB, 10 or 100 microg/ml/kg; SC) or sesame oil vehicle. Males and OVX females receiving vehicle displayed normal LI. In contrast, LI was abolished in OVX females receiving EB. The lack of LI in OVX females receiving EB was a result of low suppression ratios, reflecting strong conditioning between the tone and the shock in these subjects even if they were pre-exposed to the tone. Thus, estrogen impaired the ability of OVX females to ignore irrelevant stimuli. Since different cognitive tasks vary in their required ability to ignore irrelevant stimuli, these results may account for some of the variations in the current literature on estrogen and cognition.

Pharmacogenetic testing, informed consent and the problem of secondary information

Numerous benefits for patients have been predicted if prescribing decisions were routinely accompanied by pharmacogenetic testing. So far, little attention has been paid to the possibility that the routine application of this new technology could result in considerable harm to patients. This article emphasises that pharmacogenetic testing shares both the opportunities and the pitfalls with 'conventional' disease-genetic testing. It demonstrates that performing pharmacogenetic tests as well as interpreting the results are extraordinarily complex issues requiring a high level of expertise. It further argues that pharmacogenetic testing can have a huge impact on clinical decisions and may influence the therapeutic strategy as well as the clinical monitoring of a patient. This view challenges the predominant paradigm that pharmacogenetic testing will predict patients' responses to medicines, but that it will not provide any other significant disease-specific predictive information about the patient or family members. The article also questions published proposals to reduce the consent procedure for pharmacogenetic testing to a simple statement that the physician wishes to test a sample of the patient's DNA to see if a drug will be safe or whether it will work, and presents an alternative model that is better suited to protect patient's interests and to obtain meaningful informed consent. The paper concludes by outlining conditions for the application of pharmacogenetic testing in clinical practice in a way that can make full use of its potential benefits while minimising possible harm to patients and their families.