The Beat Goes On: The Story of Five Ageless Cardiac Drugs

Eye Diseases: When the Solution Comes from Plant Alkaloids

Plants are an incredible source of metabolites showing a wide range of biological activities. Among these, there are the alkaloids, which have been exploited for medical purposes since ancient times. Nowadays, many plant-derived alkaloids are the main components of drugs used as therapy for different human diseases. This review deals with providing an overview of the alkaloids used to treat eye diseases, describing the historical outline, the plants from which they are extracted, and the clinical and molecular data supporting their therapeutic activity. Among the different alkaloids that have found application in medicine so far, atropine and pilocarpine are the most characterized ones. Conversely, caffeine and berberine have been proposed for the treatment of different eye disorders, but further studies are still necessary to fully understand their clinical value. Lastly, the alkaloid used for managing hypertension, reserpine, has been recently identified as a potential drug for ameliorating retinal disorders. Other important aspects discussed in this review are different solutions for alkaloid production. Given that the industrial production of many of the plant-derived alkaloids still relies on extraction from plants, and the chemical synthesis can be highly expensive and poorly efficient, alternative methods need to be found. Biotechnologies offer a multitude of possibilities to overcome these issues, spanning from genetic engineering to synthetic biology for microorganisms and bioreactors for plant cell cultures. However, further efforts are needed to completely satisfy the pharmaceutical demand.

Atropine in topical formulations for the management of anterior and posterior segment ocular diseases

INTRODUCTION

Atropine is an old-known drug which is gaining increasing attention due to the myriad of therapeutic effects it may trigger on eye structures. Nevertheless, novel applications may require more adequate topical formulations.

AREAS COVERED

This review aims to gather the existing knowledge about atropine and its clinical applications in the ophthalmological field when administered topically. Atropine ocular pharmacokinetics is paid a special attention, including recent evidences of the capability of the drug to access to the posterior segment. Ocular bioavailability and systemic bioavailability are counterbalanced. Finally, limitations of traditional dosage forms and potential advantages of under investigation delivery systems are analyzed.

EXPERT OPINION

Mydriasis and cyclopegia have been widely exploited for eye examination, management of anterior segment diseases, and more recently as antidotes of chemical weapons. Improved knowledge on drug receptors and related pathways explains atropine repositioning as an outstanding tool to prevent myopia. The ease with which atropine penetrates ocular tissues is a double edged sword, that is, while it ensures therapeutic levels in the posterior segment, the unspecific distribution causes a wide variety of untoward effects. The design of formulations that can selectively deliver atropine to the target tissue for each specific application is an urgent unmet need.

Dark Classics in Chemical Neuroscience: An Evidence-Based Systematic Review of Belladonna

Belladonna has diverse pharmacotherapeutic properties with a shadowy history of beauty, life, and death. Alkaloids present in belladonna have anti-inflammatory, anticholinergic, antispasmodic, mydriatic, analgesic, anticonvulsant, and antimicrobial activities, which makes it widely applicable for the treatment of various diseases. However, because of its associated toxicity, the medicinal use of belladonna is debatable. Therefore, an evidence-based systematic review was planned to elucidate the pharmacotherapeutic potential of belladonna. A comprehensive literature search was performed in PubMed, MEDLINE, the Cochrane database, Embase, and ClinicalTrials.gov using the keywords "belladonna", "belladonna and clinical trials", and "safety and efficacy of belladonna". Articles published from 1965 to 2020 showing the efficacy of belladonna in diverse clinical conditions are included. The quality of evidence was generated using the GRADE approach, and 20 studies involving 2302 patients were included for the systematic review. Our analyses suggest that belladonna treatment appears to be safe and effective in various disease conditions, including acute encephalitis syndrome, urethral stent pain, myocardial ischemia injury, airway obstructions during sleep in infants, climacteric complaints, irritable bowel syndrome, and throbbing headache. However, better understanding of the dosage and the toxicity of tropane alkaloids of belladonna could make it an efficient remedy for treating diverse medical conditions.

Atropine eye-drop-induced acute delirium: a case report

Atropine is an anticholinergic drug which is used in both parental and topical routes. Topical eye-drops of atropine sulfate are used as mydriatic and cycloplegics. Parental atropine-induced delirium is well known but topical atropine eye-drop-induced delirium cases are very limited in literature. In this case report, an elderly man underwent cataract surgery and developed delirium after the use of 1% atropine sulfate eye-drops as prescribed. This case supports the notion that even atropine eye-drops can cause delirium in patients at therapeutic doses in elderly.

DARK Classics in Chemical Neuroscience: Atropine, Scopolamine, and Other Anticholinergic Deliriant Hallucinogens

Anticholinergic drugs based on tropane alkaloids, including atropine, scopolamine, and hyoscyamine, have been used for various medicinal and toxic purposes for millennia. These drugs are competitive antagonists of acetylcholine muscarinic (M-) receptors that potently modulate the central nervous system (CNS). Currently used clinically to treat vomiting, nausea, and bradycardia, as well as alongside other anesthetics to avoid vagal inhibition, these drugs also evoke potent psychotropic effects, including characteristic delirium-like states with hallucinations, altered mood, and cognitive deficits. Given the growing clinical importance of anti-M deliriant hallucinogens, here we discuss their use and abuse, clinical importance, and the growing value in preclinical (experimental) animal models relevant to modeling CNS functions and dysfunctions.

The Fever Tree: from Malaria to Neurological Diseases

This article describes the discovery and use of the South American cinchona bark and its main therapeutic (and toxic) alkaloids, quinine and quinidine. Since the introduction of cinchona to Europe in the 17th century, it played a role in treating emperors and peasants and was central to colonialism and wars. Over those 400 years, the medical use of cinchona alkaloids has evolved from bark extracts to chemical synthesis and controlled clinical trials. At the present time, the use of quinine and quinidine has declined, to a large extent due to their toxicity. However, quinine is still being prescribed in resource-limited settings, in severe malaria, and in pregnant women, and quinidine made a limited comeback in the treatment of several cardiac and neurological syndromes. In addition, the article presents more recent studies which improved our understanding of cinchona alkaloids' pharmacology. The knowledge gained through these studies will hopefully lead to a wider use of these drugs in precision medicine and to design of new generation, safer quinine and quinidine derivatives.