Pharmacokinetics of contraceptive steroids in patients with cystic fibrosis

Optimizing sexual and reproductive health across the lifespan in people with cystic fibrosis

With improved therapies, people with cystic fibrosis are living longer and healthier lives and increasingly have questions surrounding their sexual and reproductive health. This article will summarize the important issues of which providers should be aware during the lifespan of people with cystic fibrosis, including puberty, adulthood, and menopause. A wide range of sexual and reproductive health topics are addressed such as puberty, transgender and gender nonbinary identities, contraception, sexually transmitted infections, hypogonadism, sexual functioning, cyclical hemoptysis, and urinary incontinence. We discuss gaps in knowledge and current evidence as well as management strategies to optimize care. Our goal is to support providers to enable them to give comprehensive care throughout the lifespan of people with cystic fibrosis.

Female reproductive health in cystic fibrosis

Women with cystic fibrosis (CF) are living longer and healthier lives, and opportunities for childbearing are increasingly promising. However, this population can also face sexual and reproductive health concerns, including menstrual irregularities, unplanned pregnancies, infertility and pregnancy complications. Additionally, more women are entering menopause and are at risk for the consequences of estrogen deficiency. The exact mechanisms involved in female reproductive health conditions in CF are not clearly understood, but are thought to include cystic fibrosis transmembrane regulator (CFTR)-mediated abnormalities, changes in female sex hormones, and other CF health-related factors. In the era of CFTR modulator therapy, new data are necessary to understand the impact of CFTR modulation on contraceptive effectiveness, fertility, and pregnancy outcomes to help guide future clinical care. This article reviews the current scientific knowledge of major reproductive health issues for women with CF.

Contraceptive safety among women with cystic fibrosis: a systematic review

BACKGROUND

With dramatic improvements in life expectancy for cystic fibrosis (CF) patients, contraception for women with CF has become an important issue. There are theoretical concerns that hormonal contraceptive use among women with CF may impact disease severity or risk for other adverse health outcomes, including thrombosis and poor bone health, as well as concerns that malabsorption or altered drug metabolism might impact contraceptive effectiveness.

OBJECTIVE

To evaluate evidence on the safety and effectiveness of contraceptive methods among women with CF.

SEARCH STRATEGY

We searched the PubMed database for all articles published from database inception through October 2015.

SELECTION CRITERIA

We included studies that examined measures of disease severity, other health outcomes or indicators of contraceptive effectiveness among women with CF initiating or continuing a contraceptive method.

RESULTS

Seven studies met our inclusion criteria. Three observational studies of fair to poor quality suggest that use of oral contraceptives (OCs) does not negatively impact CF disease severity, defined as changes in pulmonary function, number of exacerbations or need for intravenous antibiotics. Three small studies of poor quality reported on contraceptive failure among women with CF using combined hormonal contraceptives (combined OCs, patch or ring). One pregnancy was reported in a patch user out of 43 hormonal contraceptive users across all studies. One pharmacokinetic study reported that women with CF achieve steroid hormone plasma concentrations similar to healthy women after ingestion of combined OCs.

CONCLUSIONS

Limited evidence suggests that hormonal contraceptive use does not negatively impact disease severity among women with CF and that hormonal contraceptive effectiveness is not impaired by CF. Studies were limited by small sample sizes and short duration of follow-up. No studies examined the effect of hormonal contraception on thrombosis or bone health among women with CF.

Pregnancy and cystic fibrosis: Approach to contemporary management

Over the previous 50 years survival of patients with cystic fibrosis has progressively increased. As a result of improvements in health care, increasing numbers of patients with cystic fibrosis are now considering starting families of their own. For the health care professionals who look after these patients, the assessment of the potential risks, and the process of guiding prospective parents through pregnancy and beyond can be both challenging and rewarding. To facilitate appropriate discussions about pregnancy, health care workers must have a detailed understanding of the various important issues that will ultimately need to be considered for any patient with cystic fibrosis considering parenthood. This review will address these issues. In particular, it will outline pregnancy outcomes for mothers with cystic fibrosis, issues that need to be taken into account when planning a pregnancy and the management of pregnancy for mothers with cystic fibrosis or mothers who have undergone organ transplantation as a result of cystic fibrosis.

Concepts of contraception for adolescent and young adult women with chronic illness and disability

Sexual behavior is common in adolescents and young adults with or without chronic illness or disability, resulting in high levels of unplanned pregnancy and STDs. Individuals with chronic illness or disability should not receive suboptimal preventive health care. These individuals have a need for counseling regarding issues of sexuality and contraception. Sexually active adolescent and young adult women can be offered safe and effective contraception if they wish to avoid pregnancy. Women with chronic illnesses and disabilities who are sexually active should also be offered contraception based on their specific medical issues. Condoms are also recommended to reduce STD risks. Table 36 summarizes basic principles of contraception application for specific illnesses, which have been identified since the release of the combined OC in 1960. Clinicians should also consider the noncontraceptive benefits of this remarkable and life-changing technology that allows all reproductive age women to improve their lives, including those with chronic illnesses and disabilities.

Contraception, communication and counseling for sexuality and reproductive health in adolescents and young adults with CF

With survival now into the fourth decade and rapid growth of the adolescent and adult population of people with cystic fibrosis CF sexual and reproductive health issues are integral to the management of adolescents and adults with CF. Education and counseling for sexual health related issues must be included in the daily routine of CF care. With advances in genetic counseling, contraception, assisted reproductive technology and collaborative management adolescents and young adults with CF realizing their sexual and reproductive potentials safely and realistically can be possible .

CYSTIC FIBROSIS – A GUIDE FOR CLINICIANS IN REPRODUCTIVE AND OBSTETRIC MEDICINE

Cystic Fibrosis (CF) is the most common life-shortening recessive genetic disease in the UK. Far from being a condition managed exclusively by paediatricians with sufferers dying in early childhood, CF is now a condition in which adults outnumber children with the condition, and the death of a child in a paediatric centre is rare. As increasing numbers of young people grow up relatively healthy it is unsurprising they begin to ask about relationships, sex, fertility and the possibility of having a child. This paper briefly describes the genetics, pathophysiology and clinical features of CF with an emphasis on how it pertains to female reproduction. The management of women with CF considering having a baby including contraception, preparation for pregnancy, the pregnancy itself, delivery and the post natal period will be discussed. Contraindications to pregnancy, method of termination, and pregnancy after transplantation will also be considered. Much of the detailed management is given in the European Guidelines for the Management of Pregnancy in Women with CF on which this paper is based.

Sexual and reproductive health knowledge in cystic fibrosis female patients and their parents

INTRODUCTION

The changing outcomes for young cystic fibrosis (CF) patients means that reproductive health issues have become an integral part of CF management.

AIM

The aim of this study was to investigate the knowledge and experiences of reproductive and sexual health issues in women with CF and to investigate the knowledge and reproductive health attitudes of their parents.

MAIN OUTCOME MEASURES

Assessment of reproductive and sexual health knowledge in female CF patients and their parents.

METHODS

A questionnaire study directed to 120 Polish women with CF aged 16 years and older and their parents.

RESULTS

Sixty-four patients and their parents responded to the questionnaire. Sixty-eight percent of the patients started sexual intercourse at a mean age of 19.2 years. Eighty-four percent of all sexually active women reported that they did not use any form of contraception. Only 32.8% of women understood the problems connected with their own and male fertility in CF. Popular scientific publications and other CF patients were identified as the most important source of information. Only 23% of parents understood the problems connected with female fertility in CF; 44% of parents thought that man with CF had normal fertility. Seventy-five percent of the women and 40% of the parents felt that sexual health discussions should begin between age 12 and 14 years with a CF doctor and the mother.

CONCLUSIONS

Our study showed that significant knowledge gaps exist regarding fertility issues in both CF patients and CF parents. Women with CF have some general knowledge about sexual issues but insufficient knowledge to have a safe sexual life. The results helped us to develop the educational program for CF patients.

A new model of cystic fibrosis pathology: Lack of transport of glutathione and its thiocyanate conjugates

Many of the symptoms of cystic fibrosis are not explained by the current disease mechanisms. Therefore, the authors conducted an extensive literature review and present a new model of cystic fibrosis pathology, which is the culmination of this research. Understanding that the cystic fibrosis transmembrane conductance regulator (CFTR) is responsible for glutathione (GSH) transport, the authors hypothesize that mutations of the CFTR, which create abnormal GSH transport, will lead to aberrations of GSH levels in both the intracellular as well as the extracellular milieu. These alterations in normal cellular GSH levels affect the redox state of the cell, thereby affecting the intracellular stress protein, metallothionein. The authors describe how this disruption of the redox state caused by excess cellular GSH, will naturally prevent the delivery of zinc as a cofactor for various enzymatic processes, and how these disruptions in normal redox may cause alterations in both humoral and cell-mediated immunity. Moreover, the symptom of thick sticky mucus in these patients might be explained through the understanding that oversulfation of mucus is a direct result of elevated cellular GSH and cysteine. The issues of hyperinflammation, altered pH and the imbalance of fatty acids that are typical in cystic fibrosis are addressed-all of which may also be linked to disruptions in GSH homeostasis. Additionally, this new model of cystic fibrosis pathology, clarifies the relationship between the CFTR and the multi-drug resistance proteins, and the lack of cell-mediated immunity by predicting that the substrate of these proteins is a glutathione adduct of thiocyanate. Finally, a new therapeutic strategy by using isothiocyanates to rectify the GSH imbalance and restore the immune system is suggested for the treatment of cystic fibrosis patients.

Individual variation in first-pass metabolism

Individual variation in pharmacokinetics has long been recognised. This variability is extremely pronounced in drugs that undergo extensive first-pass metabolism. Drug concentrations obtained from individuals given the same dose could range several-fold, even in young healthy volunteers. In addition to the liver, which is the major organ for drug and xenobiotic metabolism, the gut and the lung can contribute significantly to variability in first-pass metabolism. Unfortunately, the contributions of the latter 2 organs are difficult to quantify because conventional in vivo methods for quantifying first-pass metabolism are not sufficiently specific. Drugs that are mainly eliminated by phase II metabolism (e.g. estrogens and progestogens, morphine, etc.) undergo significant first-pass gut metabolism. This is because the gut is rich in conjugating enzymes. The role of the lung in first-pass metabolism is not clear, although it is quite avid in binding basic drugs such as lidocaine (lignocaine), propranolol, etc. Factors such as age, gender, disease states, enzyme induction and inhibition, genetic polymorphism and food effects have been implicated in causing variability in pharmacokinetics of drugs that undergo extensive first-pass metabolism. Of various factors considered, age and gender make the least evident contributions, whereas genetic polymorphism, enzymatic changes due to induction or inhibition, and the effects of food are major contributors to the variability in first-pass metabolism. These factors can easily cause several-fold variations. Polymorphic disposition of imipramine and propafenone, an increase in verapamil first-pass metabolism by rifampicin (rifampin), and the effects of food on propranolol, metoprolol and propafenone, are typical examples. Unfortunately, the contributions of these factors towards variability are unpredictable and tend to be drug-dependent. A change in steady-state clearance of a drug can sometimes be exacerbated when first-pass metabolism and systemic clearance of a drug are simultaneously altered. Therefore, an understanding of the source of variability is the key to the optimisation of therapy.

Oral contraceptives. Are drug interactions of clinical significance?

There is a large quantity of literature on drug interactions with oral contraceptive (OC) steroids although their incidence is not known. The potential clinical significance of some interactions makes it important for all prescribing doctors and dentists to have some knowledge of the topic. Interactions may be divided into those in which OC effectiveness is impaired, causing breakthrough bleeding or pregnancy, those in which OC activity is enhanced by other drugs and those in which OCs interfere with the metabolism or activity of other therapeutic agents. Consideration of their pharmacology indicates that impairment of OC effect is most likely to be due to interference with ethinylestradiol. This is because this compound is sulphated in the gut wall, hydroxylated and glucuronidated in the liver, and undergoes enterohepatic recirculation. The progestogens are only metabolised in the liver and have no significant enterohepatic recirculation. Protein binding interactions are rarely of clinical importance. OC plasma concentrations may be reduced by induction of hepatic metabolism in the case of griseofulvin, rifampicin (rifampin) and several anticonvulsant drugs; valproic acid (sodium valproate) does not have this effect. Antibiotics may interfere with enterohepatic recirculation of ethinylestradiol and reduce plasma levels of active hormone. This is probably only of significance in a subgroup of women who may sometimes be suspected on history, but cannot be identified by any diagnostic test. Reasons for differences between case reports and formal studies of interactions with antibiotics are discussed. Plasma concentrations of ethinylestradiol may be increased by ascorbic acid (vitamin C) and paracetamol (acetaminophen) which compete with it for sulphation in the gut wall. Theoretically, problems may arise if these agents are stopped suddenly. Imidazole antifungal agents can inhibit ethinylestradiol metabolism and increase its plasma concentrations but the clinical significance of this is unknown. OCs have been shown to inhibit metabolism of many therapeutic drugs and increase their plasma concentrations. This may be of clinical significance in the case of benzodiazepines which are hydroxylated in the liver, but clinical effects are less certain with the other agents. OCs may induce metabolism of other drugs which are glucuronidated, including some benzodiazepines and analgesics. The clinical significance of this type of interaction is also unknown. It is suggested that all prescribers should remember to ask about OCs when taking a drug history and to consider the possibility of interactions with other drugs.

Altered prednisolone pharmacokinetics in patients with cystic fibrosis

Prednisolone pharmacokinetics were evaluated in eight patients with cystic fibrosis (CF) (aged 1.8 to 20 years) by assessing absorption of orally administered prednisone (in its active form, prednisolone) and elimination of prednisolone after intravenous administration. After an overnight fast, subjects received intravenously administered doses of prednisolone or orally administered doses of prednisone, 40 mg/1.73 m2 body surface area, before a standardized breakfast. Serial blood samples were collected for 12 hours and analyzed for prednisolone concentration. Prednisolone pharmacokinetics were compared in eight age-matched patients with asthma who required steroids after intravenous administration of prednisolone. The prednisolone pharmacokinetic parameters derived demonstrated an increased total clearance (by 60%), an increased volume of distribution (by 46%), a lower peak concentration (by 35%), and no difference in elimination half-life in patients with CF compared with those with asthma. Bioavailability averaged 88.4% +/- 20.1% of the administered dose. Prednisolone clearance was markedly increased in those with CF. There was a proportional increase in nonrenal clearance, with no difference in renal clearance in those with asthma or CF. The plasma protein binding of prednisolone was only slightly decreased in patients with CF and did not account for the observed pharmacokinetic alteration. The marked increase in prednisolone clearance may necessitate the use of more frequent or higher doses of this steroid in the treatment of patients with CF, leading to a potentially less favorable benefit/risk ratio.

The in-vitro mucosal conjugation of ethinyloestradiol and the bioavailability of oral contraceptive steroids in patients with treated and untreated coeliac disease

The ethinyloestradiol (EO2) component of oral contraceptive steroids is extensively conjugated with sulphate by the gut wall. The ability of gastrointestinal mucosa to conjugate EO2 has been examined in vitro in samples of mucosa taken from normal women as well as from women with coeliac disease. The percentage conjugation per mg dry weight for normal tissue (n = 11) was 17.1 +/- 6.4 (mean +/- s.d.) while in untreated coeliac tissue (n = 6) the figure was 6.3 +/- 3.6% (P less than 0.01). In tissue from patients with treated coeliac disease (n = 5) the figure was 12.1 +/- 3.2%. Thus the ability of intestinal mucosa to conjugate ethinyloestradiol was significantly reduced in patients with coeliac disease, and restored towards normal following treatment. However, in patients with coeliac disease the pharmacokinetics of ethinyloestradiol were not significantly different from normal controls.

Oral contraceptive steroids--pharmacological issues of interest to the prescribing physician

Oral contraceptive steroids (OCS) are well absorbed from the gastrointestinal tract in humans. However, while the progestogens are almost completely bioavailable, ethinylestradiol (EE2) is subject to extensive first pass metabolism consisting chiefly of conjugation with sulfate in the gut wall. Both EE2 and progestogens are well absorbed in patients with an ileostomy or with diseases such as cystic fibrosis or Crohn's disease. However in patients with celiac disease (gluten-sensitive enteropathy) the gut wall is less able to conjugate EE2 and thus its bioavailability is increased. The bioavailability returns to control values as the disease is improved following gluten withdrawal. Other drugs that are conjugated with sulfate, such as vitamin C and paracetamol, compete for available sulfate when coadministered with OCS leading to high plasma levels of EE2. Enzyme-inducing agents such as rifampicin, phenobarbitone, phenytoin and carbamazepine reduce blood levels of the OCS leading to contraceptive failure. In the case of anticonvulsants (but not rifampicin) this can be easily overcome by increasing the dose of OCS used. Broad-spectrum antibiotics are reported to cause failure of contraception by interfering with the enterohepatic circulation of EE2 but limited systematic studies show no evidence of such an interaction. Nevertheless practitioners are advised to recommend the use of alternative contraceptive precautions for women receiving broad-spectrum antibiotics concurrently with their OCS preparation.

Clinical pharmacokinetics of contraceptive steroids. An update

The present article should be read in conjunction with the original review published in the Journal in 1983. There is no new information of major significance about the pharmacokinetics of levonorgestrel, norethisterone (norethindrone) or ethinylestradiol, although it has been shown that the concentrations of these hormones secreted in breast milk are small and mothers taking combined oral contraceptive steroids may breast-feed safely. Both levonorgestrel and ethinylestradiol can be successfully administered from appropriate vaginal formulations, but no clear advantages over oral administration have been demonstrated. Several new progestogens have been investigated. Desogestrel is a prodrug for its active metabolite 3-keto-desogestrel, gestodene is itself an active progestogen and norgestimate is a prodrug acting by conversion to norgestrel and its metabolites. All 3 compounds have good bioavailability with wide intersubject variation. The newer progestogens, like norethisterone and levonorgestrel, are bound to sex hormone binding globulin (SHBG). This causes their plasma concentrations to increase with time, since SHBG is induced by ethinylestradiol even in doses of 30 micrograms daily. The binding capacity and affinity of SHBG do not increase in direct proportion to its concentration. Further drug interactions with oral contraceptive steroids have been described. Contraceptive steroids may inhibit hepatic microsomal enzyme metabolism and increase the plasma concentration and effect of some tricyclic antidepressants, the hydroxylated benzodiazepines, some beta-blocking drugs, methylxanthines, prednisolone and cyclosporin. There are no significant effects on vitamins. Oral contraceptive steroids induce glucuronidation and hence decrease plasma concentrations of some benzodiazepines, clofibric acid, paracetamol (acetaminophen) and possibly morphine. The plasma concentration of ethinylestradiol may be increased by competitive sulphation with paracetamol. Plasma concentrations of contraceptive steroids are decreased by griseofulvin, which induces their hepatic metabolism. The role of other antibiotics remains controversial but there is probably a group of susceptible women who have lower plasma contraceptive hormone concentrations and experience breakthrough bleeding or pregnancy when given broad spectrum antibiotics. This may relate to interruption of the enterohepatic recirculation of ethinylestradiol. Anticonvulsants, other than valproic acid, all induce contraceptive steroid metabolism and therefore lower plasma hormone concentrations, thus reducing contraceptive effectiveness.

Factors affecting the enterohepatic circulation of oral contraceptive steroids

Oral contraceptive steroids may undergo enterohepatic circulation, but it is relevant for only estrogens, because these compounds can be directly conjugated in the liver. Animal studies show convincing evidence of the importance of the enterohepatic circulation, but studies in humans are much less convincing. The importance of the route and the rate of metabolism of ethinyl estradiol are reviewed. Some antibiotics have been reported anecdotally to reduce the efficacy of oral contraceptive steroids, but controlled studies have not confirmed this observation. Although gut flora are altered by oral antibiotics, the blood levels of ethinyl estradiol are not reduced, and one antibiotic at least (cotrimoxazole) enhances the activity of ethinyl estradiol.

Metabolism of drugs and other xenobiotics in the gut lumen and wall

Metabolism in the gut lumen and wall can decrease the bioavailability and the pharmacological effects of a wide variety of drugs. Bacterial flora in the gut, the environmental pH and oxidative or conjugative enzymes present in the intestinal epithelial cells can all contribute to the process. Bacterial biotransformation is greatest in the colon, while gut wall metabolism is generally highest in the jejunum and decreases distally. Gut wall metabolism may be induced or inhibited by dietary or environmental xenobiotics or by co-administered drugs. Recent evidence suggests that some drugs, food-derived mutagens and other xenobiotics can be metabolized by gut flora and/or gut wall enzymes to reactive species which may cause tumors.