Achilles tendinopathy following Kaletra (lopinavir/ritonavir) use

COVID-19 Therapeutics: Use, Mechanism of Action, and Toxicity (Xenobiotics)

SARS-CoV-2 emerged in 2019 and led to the COVID-19 pandemic. Efforts to develop therapeutics against SARS-Cov-2 led to both new treatments and attempts to repurpose existing medications. Here, we provide a narrative review of the xenobiotics and alternative remedies used or proposed to treat COVID-19. Most repositioned xenobiotics have had neither the feared toxicity nor the anticipated efficacy. Repurposed viral replication inhibitors are not efficacious and frequently associated with nausea, vomiting, and diarrhea. Antiviral medications designed specifically against SARS-CoV-2 may prevent progression to severe disease in at-risk individuals and appear to have a wide therapeutic index. Colloidal silver, zinc, and ivermectin have no demonstrated efficacy. Ivermectin has a wide therapeutic index but is not efficacious and acquiring it from veterinary sources poses additional danger. Chloroquine has a narrow therapeutic index and no efficacy. A companion review covers vaccines, monoclonal antibodies, and immunotherapies. Together, these two reviews form an update to our 2020 review.

The recent application of 3D-QSAR and docking studies to novel HIV-protease inhibitor drug discovery

INTRODUCTION

Despite the availability of FDA approved inhibitors of HIV protease, numerous efforts are still ongoing to achieve 'near-perfect' drugs devoid of characteristic adverse side effects, toxicities, and mutational resistance. While experimental methods have been plagued with huge consumption of time and resources, there has been an incessant shift towards the use of computational simulations in HIV protease inhibitor drug discovery.

AREAS COVERED

Herein, the authors review the numerous applications of 3D-QSAR modeling methods over recent years relative to the design of new HIV protease inhibitors from a series of experimentally derived compounds. Also, the augmentative contributions of molecular docking are discussed.

EXPERT OPINION

Efforts to optimize 3D QSAR and molecular docking for HIV-1 drug discovery are ongoing, which could further incorporate inhibitor motions at the active site using molecular dynamics parameters. Also, highly predictive machine learning algorithms such as random forest, K-means, decision trees, linear regression, hierarchical clustering, and Bayesian classifiers could be employed.

COVID-19: Therapeutics and Their Toxicities

SARS-CoV-2 is a novel coronavirus that emerged in 2019 and is causing the COVID-19 pandemic. There is no current standard of care. Clinicians need to be mindful of the toxicity of a wide variety of possibly unfamiliar substances being tested or repurposed to treat COVID-19. The United States Food and Drug Administration (FDA) has provided emergency authorization for the use of chloroquine and hydroxychloroquine. These two medications may precipitate ventricular dysrhythmias, necessitating cardiac and electrolyte monitoring, and in severe cases, treatment with epinephrine and high-doses of diazepam. Recombinant protein therapeutics may cause serum sickness or immune complex deposition. Nucleic acid vaccines may introduce mutations into the human genome. ACE inhibitors and ibuprofen have been suggested to exacerbate the pathogenesis of COVID-19. Here, we review the use, mechanism of action, and toxicity of proposed COVID-19 therapeutics.

Protease Inhibitors for the Treatment of HIV/AIDS: Recent Advances and Future Challenges

Acquired Immunodeficiency Syndrome (AIDS) is a chronic disease characterized by multiple life-threatening illnesses caused by a retro-virus, Human Immunodeficiency Virus (HIV). HIV infection slowly destroys the immune system and increases the risk of various other infections and diseases. Although, there is no immediate cure for HIV infection/AIDS, several drugs targeting various cruxes of HIV infection are used to slow down the progress of the disease and to boost the immune system. One of the key therapeutic strategies is Highly Active Antiretroviral Therapy (HAART) or ' AIDS cocktail' in a general sense, which is a customized combination of anti-retroviral drugs designed to combat the HIV infection. Since HAART's inception in 1995, this treatment was found to be effective in improving the life expectancy of HIV patients over two decades. Among various classes of HAART treatment regimen, Protease Inhibitors (PIs) are known to be widely used as a major component and found to be effective in treating HIV infection/AIDS. For the past several years, a variety of protease inhibitors have been reported. This review outlines the drug design strategies of PIs, chemical and pharmacological characteristics of some mechanism-based inhibitors, summarizes the recent developments in small molecule based drug discovery with HIV protease as a drug target. Further discussed are the pharmacology, PI drug resistance on HIV PR, adverse effects of HIV PIs and challenges/impediments in the successful application of HIV PIs as an important class of drugs in HAART regimen for the effective treatment of AIDS.

Cephalexin-associated Achilles Tendonitis: Case Report and Review of Drug-induced Tendinopathy

Tendon disorders include tenosynovitis or tendonitis, tendinosis, and tendon rupture. Tendinopathy associated with drug administration has been associated with the systemic or local administration of several medications. A 90-year-old man who developed toxic tendinopathy after receiving cephalexin 500 mg twice daily has been described. Unilateral pain of his left Achilles tendon pain during walking appeared three weeks after starting the antibiotic. The drug was stopped after four weeks of treatment; within one week after discontinuing the cephalexin, all tendonitis symptoms spontaneously resolved. Drug-induced tendinopathy has most commonly been associated with fluoroquinolones, statins, glucocorticoids, and aromatase inhibitors. In addition, other systemic agents have caused tendinopathy; they include amlodipine, anabolic steroids, antiretrovirals, isotretinoin, renin-angiotensin II receptor antagonists, rituximab, and sitagliptin. Albeit less frequent, other oral antibiotics, including cephalosporins, azithromycin, and sulfonamides, have also been associated with toxic tendinopathy. Also, injections of collagenase Clostridium histolyticum, corticosteroids, and polidocanol have been followed by tendon rupture. The features of tendinopathy associated with drug treatment are summarized and their postulated mechanisms of pathogenesis are reviewed. The onset of tendon pain following the initiation of treatment with a new medication, especially if the agent has previously been associated with drug-induced tendonitis, tendinosis, or tendon rupture, should prompt the consideration of drug-associated toxic tendinopathy.

HIV protease inhibitors: a review of molecular selectivity and toxicity

Highly active antiretroviral therapy (HAART) is recognized as the most effective treatment method for AIDS, and protease inhibitors play a very important role in HAART. However, poor bioavailability and unbearable toxicity are their common disadvantages. Thus, the development of safer and potentially promising protease inhibitors is eagerly needed. In this review, we introduced the chemical characteristics and associated side effects of HIV protease inhibitors, as well as the possible off-target mechanisms causing the side effects. From the chemical structures of HIV protease inhibitors and their possible off-target molecules, we could obtain hints for optimizing the molecular selectivity of the inhibitors, to provide help in the design of new compounds with enhanced bioavailability and reduced side effects.