Exogenous Cushing's syndrome as a result of ritonavir–budesonide interaction – A case report

Iatrogenic Cushing's Syndrome: The Result of Cobicistat and Glucocorticoid Interaction in an HIV Patient After Bariatric Surgery

Cobicistat, used as a pharmacokinetic booster in therapeutic combination with human immunodeficiency virus (HIV) protease inhibitors and integrase inhibitors, is a strong inhibitor of cytochrome P450 3A4 (CYP3A4). Since most glucocorticoids are metabolized by the isoenzyme of the cytochrome P450 pathway, their plasma concentrations can be highly increased in the presence of cobicistat-boosted darunavir, with subsequent risk of iatrogenic Cushing's syndrome (ICS) and secondary adrenal insufficiency. We report a case of a 45-year-old man with HIV-hepatitis C virus co-infection treated with raltegravir and darunavir/cobicistat since 2019. In May 2021, he underwent a sleeve gastrectomy due to morbid obesity (BMI: 50.9 kg/m2) with multiple comorbidities. Four months after surgery, he was diagnosed with asthma and was started on inhaled budesonide, which was later changed to fluticasone propionate. At the 12-month postoperative visit, the patient referred proximal muscle weakness and asthenia, and suboptimal weight loss (excess weight loss of 39%) and high blood pressure were documented. Moon facies, buffalo hump, and abdominal large vinous striae were evident on physical examination. Laboratory studies showed impaired glucose metabolism and hypokalemia. Cushing's syndrome was suspected and further investigation confirmed its iatrogenic origin. The diagnosis of ICS and consequent secondary adrenal insufficiency due to an interaction between the darunavir/cobicistat combination and budesonide/fluticasone was established. Darunavir/cobicistat therapy was replaced by dolutegravir/doravirine dual therapy, inhaled corticoid was switched to beclomethasone, and glucocorticoid substitutive therapy was introduced. This is a particular case of overt ICS due to cobicistat-inhaled corticosteroid interaction in a superobese patient, developed after he underwent bariatric surgery. The presence of morbid obesity, combined with the rarity of this pharmacological complication in individuals taking cobicistat, made the correct diagnosis even more challenging. A meticulous review of pharmacologic habits and potential interactions is essential to avoid serious harm to patients.

Prescribing intranasal steroids in HIV-positive patients: systematic review of the literature

BACKGROUND

There are significant drug-drug interactions between human immunodeficiency virus antiretroviral therapy and intranasal steroids, leading to high serum concentrations of iatrogenic steroids and subsequently Cushing's syndrome.

METHOD

All articles in the literature on cases of intranasal steroid and antiretroviral therapy interactions were reviewed. Full-length manuscripts were analysed and the relevant data were extracted.

RESULTS

A literature search and further cross-referencing yielded a total of seven reports on drug-drug interactions of intranasal corticosteroids and human immunodeficiency virus protease inhibitors, published between 1999 and 2019.

CONCLUSION

The use of potent steroids metabolised via CYP3A4, such as fluticasone and budesonide, are not recommended for patients taking ritonavir or cobicistat. Mometasone should be used cautiously with ritonavir because of pharmacokinetic similarities to fluticasone. There was a delayed onset of symptoms in many cases, most likely due to the relatively lower systemic bioavailability of intranasal fluticasone.

Pharmacist-led pre-treatment assessment, management and outcomes in a Hepatitis C treatment patient cohort

Background Medication reconciliation and drug-drug interaction management represent important patient safety processes completed by pharmacists as part of Hepatitis C patient care. Objectives To describe the pharmacist-led interventions of medication reconciliation and drug-drug interaction assessment, grading and management in a real-world Hepatitis C treatment cohort and to assesses the impact on patient outcomes. Setting Two Hepatitis C hospital outpatient clinics at St. James's Hospital, Dublin. Method Patients treated with Hepatitis C direct acting anti-viral agents between December 2014 and February 2017 were included in this retrospective cohort study. The study employed a standardised medication reconciliation proforma and drug-drug interaction reference list. Main outcome measures Analyse medication variances identified during pharmacist-led medication reconciliation. Assess the prevalence, type and severity of drug-drug interactions between direct acting anti-virals and co-medications. Assess the rate of prescriber acceptance of the pharmacist-developed drug-drug interaction management strategies. Results Among the 300 patients in this study, medication reconciliation identified 1543 co-medications, with 71% of patients prescribed co-medications which were subject to a potential drug-drug interaction. Drug-drug interaction assessments assigned a rating of severe to 68 interaction episodes. At least one co-medication was stopped during treatment in 25% of patients to facilitate drug-drug interaction management. Pharmacist proposed management recommendations were accepted by prescribers in 96.9% of cases. The sustained virological response rate among the cohort was 92.7%. Conclusions In this Hepatitis C pre-treatment pharmacist assessment analysis, a significant number of medication reconciliation variances and clinically significant drug-drug interactions were identified which present unique and important patient safety risks. Pharmacist-led management strategies aided the achievement of optimum treatment response while promoting patient safety and antiviral stewardship.