Evaluation of HIV drug interaction web sites

Antiretroviral drug-drug interactions: A comparison of online drug interaction databases

WHAT IS KNOWN AND OBJECTIVE

Antiretrovirals have a high drug interaction potential, which can lead to increased toxicity and/or decreased efficacy. Multiple databases are available to assess drug-drug interactions. The aim of our study was to compare interaction identification for commonly used ARVs and concomitant medications between six different online drug-drug interaction databases.

COMMENT

This was a cross-sectional review using each of the following six databases: LexiComp®, Clinical Pharmacology®, Micromedex®, Epocrates®, University of Liverpool, and University of Toronto. Sixteen antiretroviral drugs and 100 of the DrugStats Database "Top 200 of 2019" list of medications were included. Each of the six databases identified a different number of actual or potential interactions. The number of interactions ranged from 211 to 283.

WHAT IS NEW AND CONCLUSIONS

A variety of databases exist with inconsistent identification of actual or potential drug-drug interactions amongst them. It may be beneficial to cross-reference multiple databases prior to making decisions regarding patient care.

Getting to the Heart of the Matter: A Review of Drug Interactions Between HIV Antiretrovirals and Cardiology Medications

The past 20 years have seen remarkable advances in the treatment of HIV such that most people diagnosed with HIV today can live long, healthy lives by taking antiretrovirals which are usually life-long. Advancements in antiretroviral therapy include the availability of well tolerated, single tablet regimens that are associated with a lower risk of drug-drug interactions. Despite this, many people living with HIV infection might be taking antiretroviral agents that are associated with significant drug-drug interactions. Because HIV infection itself is associated with cardiovascular complications and this population is living longer, concomitant use of antiretrovirals and medications to treat cardiovascular-related diseases is often required. For this reason, it is imperative that clinicians are aware of the potential for clinically significant drug-drug interactions between antiretroviral agents and cardiac medications as well as the useful HIV drug interaction resources that might provide guidance. Available data on significant interactions are summarized and suggested guidance regarding management is discussed.

A review of drug-drug interactions in older HIV-infected patients

INTRODUCTION

The number of older HIV-infected people is growing due to increasing life expectancies resulting from the use of antiretroviral therapy (ART). Both HIV and aging increase the risk of other comorbidities, such as cardiovascular disease, osteoporosis, and some malignancies, leading to greater challenges in managing HIV with other conditions. This results in complex medication regimens with the potential for significant drug-drug interactions and increased morbidity and mortality. Area covered: We review the metabolic pathways of ART and other medications used to treat medical co-morbidities, highlight potential areas of concern for drug-drug interactions, and where feasible, suggest alternative approaches for treating these conditions as suggested from national guidelines or articles published in the English language. Expert commentary: There is limited evidence-based data on ART drug interactions, pharmacokinetics and pharmacodynamics in the older HIV-infected population. Choosing and maintaining effective ART regimens for older adults requires consideration of side effect profile, individual comorbidities, interactions with concurrent prescriptions and non-prescription medications and supplements, dietary patterns with respect to dosing, pill burden and ease of dosing, cost and affordability, patient preferences, social situation, and ART resistance history. Practitioners must remain vigilant for potential drug interactions and intervene when there is a potential for harm.

Understanding and preventing drug-drug and drug-gene interactions

Concomitant administration of multiple drugs can lead to unanticipated drug interactions and resultant adverse drug events with their associated costs. A more thorough understanding of the different cytochrome P450 isoenzymes and drug transporters has led to new methods to try to predict and prevent clinically relevant drug interactions. There is also an increased recognition of the need to identify the impact of pharmacogenetic polymorphisms on drug interactions. More stringent regulatory requirements have evolved for industry to classify cytochrome inhibitors and inducers, test the effect of drug interactions in the presence of polymorphic enzymes, and evaluate multiple potentially interacting drugs simultaneously. In clinical practice, drug alert software programs have been developed. This review discusses drug interaction mechanisms and strategies for screening and minimizing exposure to drug interactions. We also provide future perspectives for reducing the risk of clinically significant drug interactions.

Important Drug-Drug Interactions in HIV-Infected Persons on Antiretroviral Therapy: An Update on New Interactions Between HIV and Non-HIV Drugs

Advances in antiretroviral therapy have turned HIV into a chronic, manageable disease. Patients often require treatment for co-morbid conditions as well as HIV, and consequently, pharmacokinetic interactions between antiretrovirals (ARVs) and other drug classes are an increasing concern. Protease inhibitors and non-nucleoside reverse transcriptase inhibitors are involved in the CYP450 or other transporter systems, and may be associated with higher risk of clinically significant drug interactions. One reverse transcriptase inhibitor, abacavir, has demonstrated weak inhibition of CYP3A4, 2D6 and 2C9 in vitro, but is not associated with any clinically significant interactions involving the CYP450 system. The integrase inhibitor raltegravir is not involved in the CYP450 system, and may be a suitable option to use when trying to minimize interactions with other drug classes. This review summarizes recently published data on clinically significant drug interactions between ARVs and other drug classes including antineoplastics, immunosuppressant transplant drugs, directly acting antivirals for hepatitis C, antifungals, antimalarials, corticosteroids, psychotropics, hormonal contraceptives, anticoagulants, drugs for pulmonary hypertension, and herbal products. In situations of suspected or potential interactions, close monitoring is warranted, and dose adjustments or substitutions may be required.

Online resources for persons recently diagnosed with HIV/AIDS: an analysis of HIV-related webpages

The Internet is a major source of HIV-related information and resources for persons recently diagnosed with HIV/AIDS (PRDHA). This study examined the types of HIV-related websites that appear as a result of HIV-related keyword searches and the extent to which website information targets PRDHA. The first page of HIV-related webpages from 18 keyword searches was coded. Among 137 webpages meeting inclusion criteria, 63% represented HIV-informational websites, 31% targeted HIV-positive individuals, and over half contained or provided access to HIV prevention, treatment, and transmission information. Thirty-three percent of webpages contained or provided access to PRDHA-targeted information, with a greater percentage of those webpages having mobile, non-English, and "Ask the Expert" features compared with non-PRDHA targeted webpages. Implications for PRDHA include the following: (1) they should explore HIV-related websites to gain insight into the credibility of the information contained on those sites; (2) PRDHA must be aware that HIV-related websites have the potential to elicit dated, emotionally distressing, or irrelevant information; and (3) to obtain information that relates to their demographic and situational profile, they may wish to use specific key terms (e.g., "HIV women") rather than attempting to navigate webpages that arise from general search terms (e.g., "HIV"). Recommendations for future development of online resources for PRDHA include providing HIV-relevant information in a stepwise fashion, providing demographically targeted HIV information, and greater utilization of mobile technology.

Outcomes of dosage adjustments used to manage antiretroviral drug interactions

Dosage adjustments are often used to manage HIV drug interactions, but little is known about their clinical significance. We examined patients from the Ontario HIV Cohort Study to assess the effects of dosage adjustments on plasma viral load. A significant reduction (0.67 log10 copies/mL) in viral load was associated with adjustments to manage efavirenz-based interactions (95% confidence interval, -1.33 to -0.01) but was not observed after adjustments to manage rifabutin-based (difference in viral load, 0.03 log10 copies/mL; 95% confidence interval, -0.71 to 0.77) or nevirapine-based interactions (difference in viral load, 0.09 log10 copies/mL; 95% confidence interval, -0.83 to 1.01).

Review: mixing new cocktails: drug interactions in antiretroviral regimens

Current highly active antiretroviral therapy (HAART) for the treatment of HIV infection requires the concomitant administration of three or four different agents, often with a high potential for drug-drug interactions. Additionally, some HIV-positive patients still require concomitant treatment with drugs for opportunistic infections, some require medication to treat unrelated medical conditions and/or the metabolic complications of antiretroviral therapy, others may self-medicate with herbal formulations and/or over-the-counter drugs, and still others many take drugs for recreational reasons or to manage addiction. Therefore, the virtually limitless number of drug combinations that may be taken by patients undergoing treatment of HIV infection makes drug-drug interactions almost inevitable. Managing these interactions is one of the major challenges associated with the multidrug regimens used for HIV therapy. This paper provides an overview of the most common interactions between antiretrovirals in the same and different classes-nucleoside analogue reverse transcriptase inhibitors (NRTI), protease inhibitors (PI), and non-nucleoside reverse transcriptase inhibitors (NNRTI)-by focusing on principles rather than specific interactions. The paper also addresses interactions between these antiretrovirals and other commonly used medications that may be prescribed concomitantly.