Ritonavir-fluticasone interaction causing Cushing syndrome in HIV-infected children and adolescents

Nonrespiratory Comorbidities in Asthma

Asthma is a chronic heterogeneous airway disease. Common comorbid conditions are often disproportionately present in severe asthma. Optimal care of patients with asthma requires the recognition and treatment of these comorbid conditions. This review outlines the pathophysiological mechanisms between nonrespiratory comorbid conditions and asthma and their effect on asthma outcomes. They include: type 2 diabetes mellitus, hypertension, atherosclerotic cardiovascular disease, adrenal and thyroid gland diseases, pregnancy, osteoporosis, adverse effects from medications, and mental health disorders. Studies indicate how poor glycemic control of type 2 diabetes mellitus is associated with not only greater health care utilization but poorer asthma outcomes. Also, a large health care claims database indicates that a substantial proportion of pregnant women have uncontrolled asthma and are prescribed suboptimal controller therapy. Additional data about these nonrespiratory comorbidities and medications known to benefit both nonrespiratory comorbidities and asthma are necessary.

HIV-related chronic lung disease in adolescents: are we prepared for the future?

INTRODUCTION

Chronic lung diseases (CLD) are the most chronic disease occurring in adolescents living with human immunodeficiency virus (ALHIV). In ALHIV who received antiretroviral therapy (ART) late in childhood, bronchiectasis, bronchiolitis obliterans and interstitial pneumonitis are common. In adolescents who received ART early in life the spectrum of CLD has changed with asthma and chronic obstructive pulmonary disease being common. Areas covered: The aim of this paper was to review CLD in ALHIV. We conducted a literature review of electronic databases focusing on CLD that were common prior to the introduction of ART (1996-2004), the present situation where ART is widely available (2005 to 2016), and articles which aided us speculating on the impact of HIV-related CLD in adolescents transitioning to adult HIV-clinics. Amongst the approximately 2.1 million adolescents living with HIV, CLD commonly occurs. Awareness of the CLD amongst ALHIV needs to be raised to ensure that disease appropriate treatment is available to these vulnerable adolescents. Expert commentary: As adolescents' transition from pediatric HIV-clinics to adult HIV-clinics the evidence shows that adolescents might not receive optimal care if adult pulmonologists are not aware of the CLD that commonly occur in ALHIV.

Iatrogenic Cushing syndrome and adrenal insufficiency during concomitant therapy with ritonavir and fluticasone

Ritonavir is a potent inhibitor of the cytochrome P450 enzyme CYP3A4 and is subject to multiple drug–drug interactions. This becomes especially important when the patient is also taking medications metabolized through CYP3A pathway as increased and potentially toxic drug levels may ensue. Herein we present one such interaction wherein a 57 year old gentleman with human immunodeficiency virus (HIV) infection on highly active antiretroviral therapy that included ritonavir, had addition of fluticasone inhaler to his medication repertoire for treatment of chronic obstructive pulmonary disease. This resulted in severe osteoporosis, iatrogenic Cushing syndrome and adrenal insufficiency due to the potentiated systemic glucocorticoid effect of inhaled fluticasone by ritonavir. This case emphasizes the need for pharmacovigilance when managing patients on complex drug regimens for physicians treating HIV infected patients.

Iatrogenic Cushing's syndrome induced by posaconazole

Iatrogenic Cushing's syndrome is an undesirable outcome of glucocorticoids treatment. It can be increased by pharmacologic interactions. Glucocorticoid therapy, given in association with ritonavir, and some azole treatments are causes of iatrogenic Cushing's syndrome. We present a patient with common-variable immunodeficiency who received 7 years of itraconazole therapy for bronchial colonization with Aspergillus in combination with inhaled fluticasone without any Cushingoid symptoms. After a switch to posaconazole, the patient developed Cushingoid symptoms.

Inhaled corticosteroid use in HIV-positive individuals taking protease inhibitors: a review of pharmacokinetics, case reports and clinical management

As a consequence of inhibition of the hepatic cytochrome P450 3A4 isozyme, treatment with HIV protease inhibitors can result in significant drug-drug interactions. One noteworthy interaction is between protease inhibitors and inhaled or intranasal corticosteroids. This interaction can result in adrenal insufficiency and iatrogenic Cushing's syndrome (with symptoms such as rapid weight gain, obesity, facial hirsutism and swelling), as well as hypertension, osteoporosis and decreased CD4 cell count. In this paper, we review and unite pharmacokinetic data, case reports and current research regarding this drug-drug interaction in order to suggest options for the clinical management of HIV-positive patients requiring treatment with protease inhibitors and inhaled or intranasal corticosteroids.

Increased risk of asthma and atopic dermatitis in perinatally HIV-infected children and adolescents

The incidence of asthma and atopic dermatitis (AD) was evaluated in HIV-infected (n = 451) compared to HIV-exposed (n = 227) but uninfected (HEU) children and adolescents by abstraction from clinical charts. Asthma was more common in HIV-infected compared to HEU children by clinical diagnosis (25% vs. 20%, p = 0.101), by asthma medication use, (31% vs. 22%, p = 0.012), and by clinical diagnosis and/or medication use, (34% vs. 25%, p = 0.012). HIV-infected children had a greater risk of asthma compared to HEU children (HR = 1.37, 95% CI: 1.01 to 1.86). AD was more common in HIV-infected than HEU children (20% vs. 12%, p = 0.009)) and children with AD were more likely to have asthma in both cohorts (41% vs. 29%, p = 0.010). HIV-infected children and adolescents in this study had an increased incidence of asthma and AD, a finding critical for millions of HIV-infected children worldwide.

Inhaled fluticasone causes iatrogenic cushing's syndrome in patients treated with Ritonavir

INTRODUCTION

Ritonavir, a protease inhibitor (PI), is commonly used in the treatment of HIV-1 infection. It is a potent inhibitor of the hepatic cytochrome P450 superfamily. Therefore, its usage with other PI medications leads to significant increases in the levels of the latter PI, which allows a reduction in pill burden. Intranasal and inhaled corticosteroids are widely used for the treatment of allergic rhinitis and asthma. Inhaled steroids do not usually lead to systemic adverse events, since their plasma concentrations are quite low due to extensive first-pass metabolism and clearance by CYP3A4. However, the coadministration of Ritonavir with inhaled (or intranasal) corticosteroids may result in an increase in the plasma corticosteroid levels due to the potent CYP3A4 inhibition by Ritonavir. This may cause Cushing's syndrome (laboratory and clinical) with adrenal suppression.

METHODS

Plasma cortisol and urinary-free cortisol levels were determined using immunoassays. In the Synacthen test, plasma cortisol levels were measured at time 0 as well as at times 60, 120, and 150 minutes following an intramuscular injection of 0.25 mg Synacthen.

RESULTS

We present here three HIV-1 female patients aged 12, 55 and 65 years who developed iatrogenic Cushing's syndrome with adrenal suppression following the coadministration of Ritonavir and inhaled Fluticasone, both at the standard recommended doses.

CONCLUSIONS

The coadministration of Ritonavir and Fluticasone at the recommended doses caused, in our three patients, iatrogenic Cushing's syndrome with adrenal suppression. We suggest that this adverse event is underdiagnosed and high clinical suspicion is needed for early diagnosis and prenention of Addisonian crises. Thus, Fluticasone treatment should be avoided in patients who are treated with Ritonavir. Alternative therapeutic options for asthma control such as oral Montelukast or bronchodilators alone should be considered.

Impact of antiretroviral therapy on growth, body composition and metabolism in pediatric HIV patients

Highly active antiretroviral therapy improves survival and growth in children with HIV infection. However, its use can be associated with adverse changes in body composition and metabolism. Bone mineral density can be adversely affected in HIV-positive children due to nutritional compromise or certain antiretrovirals. HIV-associated lipodystrophy, consisting of redistribution of adipose tissue, insulin resistance, and dyslipidemia, has also been described in children. Pediatric HIV patients may be at greater risk for these problems because of their longer potential lifetime exposure to these agents and because childhood is normally a period of rapid growth and tissue accretion. Healthcare providers for children with HIV infection must be aware of the potential complications associated with HIV antiretrovirals so that their antiviral efficacy can be balanced against their risk for side effects. In this review, we discuss the alterations in childhood growth and body composition that occur in HIV-infected children, and describe the impact of antiretroviral therapy on these outcomes. The problem of HIV-associated lipodystrophy syndrome in children is also discussed. Children with HIV should have their growth and body composition systematically monitored. Antiretroviral regimens should be tailored to optimize adherence and viral suppression while minimizing the potential for adverse side effects.

Iatrogenic Cushing's syndrome in HIV-infected patients receiving ritonavir and inhaled fluticasone: description of 4 new cases and review of the literature

Protease inhibitors boosted with ritonavir can lead to drug-drug interactions, particularly with inhaled corticosteroids such as fluticasone, because of the potent inhibition of cytochrome P450-3A4 activity. We report 4 cases of iatrogenic Cushing's syndrome after concomitant administration of inhaled fluticasone and antiretroviral therapy including a protease inhibitor boosted with ritonavir. Although typical manifestations were present, diagnosis of Cushing's syndrome was delayed because the patients were suspected to have antiretroviral therapy-associated lipodystrophy, which shares common clinical features with Cushing's syndrome. Biochemical tests confirmed iatrogenic Cushing's syndrome and clinical symptoms resolved after stopping ritonavir or fluticasone. The differences between the clinical symptoms of Cushing's syndrome and lipodystrophy are discussed as well as their frequency in the cases reported in the literature. The recommendation that concomitant administration of inhaled or intranasal fluticasone and ritonavir be prohibited must be implemented among practitioners who treat HIV-infected patients, and if long-term inhaled steroids are required, other drugs should be preferred.

Antibodies as a probe in cytochrome P450 research

Cytochrome P450 (P450) is the superfamily of enzymes responsible for biotransformation of endobiotics and xenobiotics. However, their large isoform multiplicity, inducibility, diverse structure, widespread distribution, polymorphic expression, and broad overlapping substrate specificity make it difficult to measure the precise role of each individual P450 to the metabolism of drugs (or carcinogens) and hamper the understanding of the relationship between the genetic/environmental factors that regulate P450 phenotype and the responses of the individual P450s to drugs. The antibodies against P450s have been useful tools for the quantitative determination of expression level and contribution of the epitope-specific P450 to the metabolism of a drug or carcinogen substrate in tissues containing multiple P450 isoforms and for implications in pharmacogenetics and human risk assessment. In particular, the inhibitory antibodies are uniquely suited for reaction phenotyping that helps to predict human pharmacokinetics for clinical drug-drug interaction potential in drug discovery and development.

Influence of antiretroviral drugs on the pharmacokinetics of prednisolone in HIV-infected individuals

BACKGROUND

Corticosteroids are cytochrome P450 3A4 substrates, which have been associated with toxicities in patients receiving cytochrome P450 3A4 inhibitors such as human immunodeficiency virus protease inhibitors. In a study in healthy volunteers, ritonavir significantly increased prednisolone exposure.

METHODS

We investigated the influence of antiretroviral (ARV) medications on prednisolone pharmacokinetics in 3 groups of 10 human immunodeficiency virus-infected subjects. One group received lopinavir/ritonavir, and another efavirenz, as part of their ARV regimen; a third group did not receive ARV medications. Each subject received a single 20-mg prednisone dose followed by serial blood sampling for prednisolone. Prednisolone pharmacokinetics were compared among the groups.

RESULTS

Area under the concentration-time curve was significantly lower in efavirenz recipients versus subjects receiving lopinavir/ritonavir (geometric mean ratio = 0.60, P = 0.01). Average prednisolone area under the concentration-time curve was higher in subjects taking lopinavir/ritonavir versus subjects not on ARVs; however, this difference was not significant (P > 0.05).

CONCLUSIONS

These data indicate that prednisolone concentrations may fluctuate widely when human immunodeficiency virus-positive individuals established on efavirenz therapy change to lopinavir/ritonavir or vice versa.

Cytochrome P450 reaction-phenotyping: an industrial perspective

It is now widely accepted that the fraction of the dose metabolized by a given drug-metabolizing enzyme is one of the major factors governing the magnitude of a drug interaction and the impact of a polymorphism on (total) drug clearance. Therefore, most pharmaceutical companies determine the enzymes involved in the metabolism of a new chemical entity (NCE) in vitro, in conjunction with human data on absorption, distribution, metabolism and excretion. This so called reaction-phenotyping, or isozyme-mapping, usually involves the use of multiple reagents (e.g., recombinant proteins, liver subcellular fractions, enzyme-selective chemical inhibitors and antibodies). For the human CYPs, reagents are readily available and in vitro reaction-phenotyping data are now routinely included in most regulatory documents. Ideally, the various metabolites have been definitively identified, incubation conditions have afforded robust kinetic analyses, and well characterized (high quality) reagents and human tissues have been employed. It is also important that the various in vitro data are consistent (e.g., scaled turnover with recombinant CYP proteins, CYP inhibition and correlation data with human liver microsomes) and enable an integrated in vitro CYP reaction-phenotype. Results of the in vitro CYP reaction-phenotyping are integrated with clinical data (e.g., human radiolabel and drug interaction studies) and a complete package is then submitted for regulatory review. If the NCE receives market approval, information on key routes of clearance and their associated potential for drug-drug interactions are included in the product label. The present review focuses on in vitro CYP reaction-phenotyping and the integration of data. Relatively simple strategies enabling the design and prioritization of follow up clinical studies are also discussed.

Unusual causes of Cushing's syndrome

Although in the majority of the patients with Cushing's syndrome (CS), hypercortisolism is due to ACTH hypersecretion by a pituitary tumour or to ectopic ACTH secretion from an extrapituitary neoplastic lesion or to autonomous cortisol secretion by an adrenal tumour, in occasional patients a much rarer entity may be the cause of the syndrome. Herein, we attempted to summarise and categorise these unusual causes according to their presumed aetiology. To this end, we performed a comprehensive computer-based search for unusual or rare causes of CS. The following unusual forms of CS were identified: (i) ACTH hyperesecretion due to ectopic corticotroph adenomas in the parasellar region or the neurohypophysis, or as part of double adenomas, or gangliocytomas; (ii) ACTH hypersecretion due to ectopic CRH or CRH-like peptide secretion by various neoplasms; (iii) ACTH-independent cortisol hypersecretion from ectopic or bilateral adrenal adenomas; (iv) glucocorticoid hypersensitivity; (v) iatrogenic, due to megestrol administration or to ritonavir and fluticasone co-administration. Such unusual presentations of CS illustrate why Cushing's syndrome represents one of the most puzzling endocrine syndromes.

Mechanisms of Pharmacokinetic and Pharmacodynamic Drug Interactions Associated with Ritonavir-Enhanced Tipranavir

Tipranavir is a nonpeptidic protease inhibitor that has activity against human immunodeficiency virus strains resistant to multiple protease inhibitors. Tipranavir 500 mg is coadministered with ritonavir 200 mg. Tipranavir is metabolized by cytochrome P450 (CYP) 3A and, when combined with ritonavir in vitro, causes inhibition of CYP1A2, CYP2C9, CYP2C19, CYP2D6, and CYP3A in addition to induction of glucuronidase and the drug transporter P-glycoprotein. As a result, drug-drug interactions between tipranavir-ritonavir and other coadministered drugs are a concern. In addition to interactions with other antiretrovirals, tipranavir-ritonavir interactions with antifungals, antimycobacterials, oral contraceptives, statins, and antidiarrheals have been specifically evaluated. For other drugs such as antiarrhythmics, antihistamines, ergot derivatives, selective serotonin receptor agonists (or triptans), gastrointestinal motility agents, erectile dysfunction agents, and calcium channel blockers, interactions can be predicted based on studies with other ritonavir-boosted protease inhibitors and what is known about tipranavir-ritonavir CYP and P-glycoprotein utilization. The highly complex nature of drug interactions dictates that cautious prescribing should occur with narrow-therapeutic-index drugs that have not been specifically studied. Thus, the known interaction potential of tipranavir-ritonavir is reported, and in vitro and in vivo data are provided to assist clinicians in predicting interactions not yet studied. As more clinical interaction data are generated, better insight will be gained into the specific mechanisms of interactions with tipranavir-ritonavir.

Exogenous Cushing syndrome with inhaled fluticasone in a child receiving lopinavir/ritonavir

OBJECTIVE

To describe a case of Cushing syndrome in a child during concurrent use of inhaled fluticasone propionate, nasal mometasone, and a highly active antiretroviral regimen including lopinavir/ritonavir.

CASE SUMMARY

A 9-year-old boy with HIV infection and asthma developed moon facies, increased facial hair, and increased weight after fluticasone propionate inhalation (1 puff; 220 microg) therapy was begun. His antiretroviral regimen contained the protease inhibitor combination lopinavir/ritonavir at a dose of 216/54 mg twice daily, and he had been stable for the previous 5 years. He had also been receiving intranasal mometasone for 11 months for the management of allergic rhinitis. Serum cortisol and adrenocorticotropic hormone levels were consistent with adrenal suppression. These physical findings and symptoms and laboratory values normalized after discontinuation of the fluticasone propionate. The Naranjo probability scale indicated that a probable interaction occurred between lopinavir/ritonavir and fluticasone propionate, leading to subsequent adrenal suppression.

DISCUSSION

Protease inhibitors are associated with numerous drug interactions due to inhibition of the CYP3A4 isoenzyme. Pharmaceutical agents used to treat comorbidities in HIV-infected individuals often can interact with protease inhibitors, leading to toxic drug concentrations or untoward effects. Inhaled corticosteroids such as fluticasone propionate are often necessary to treat asthma in young children and are metabolized by CYP3A4. Interactions between protease inhibitors and inhaled fluticasone propionate have been reported in the adult population, but reports are limited in the pediatric literature.

CONCLUSIONS

This case raises awareness of the interaction between fluticasone propionate and lopinavir/ritonavir and adverse effects in children receiving both medications.