{"id":50772,"date":"2019-12-28T15:32:16","date_gmt":"2019-12-28T23:32:16","guid":{"rendered":"https:\/\/selfhacked.com\/?p=50772"},"modified":"2021-11-03T02:12:37","modified_gmt":"2021-11-03T09:12:37","slug":"anticholinergics","status":"publish","type":"post","link":"https:\/\/selfhacked.com\/blog\/anticholinergics\/","title":{"rendered":"Anticholinergics: What They Do, How They Work & Potential Uses"},"content":{"rendered":"

\u201cAnticholinergics<\/em>\u201d are drugs or other substances that either block or reduce the activity of the neurotransmitter acetylcholine<\/em> throughout the body and brain. Some natural, plant-based anticholinergic compounds have a long history of use in traditional forms of folk medicine, while other, more modern anticholinergic drugs are routinely used by medical professionals to treat a wide variety of specific symptoms or conditions. In this post, we\u2019ll provide an overview of what these compounds are, how they work, and review some of the current or potential applications of these compounds. Read on to learn more about the interesting science behind these drugs!<\/p>\n

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Disclaimer:<\/em><\/strong> This article is not a recommendation or endorsement for any of the drugs or other compounds mentioned throughout this post. Many of these medications have only been FDA-approved for the treatment of certain specific medical conditions, and most can only be safely and legally taken by prescription and with oversight from a licensed medical professional. We have written this post for informational purposes only, and our goal is solely to inform people about the science behind these drugs\u2019 effects, biological mechanisms, and potential health applications. None of the information in this post should ever be used to replace conventional medical care or treatment \u2014 and always be sure to discuss any new supplements or medications with your doctor first!<\/em><\/p>\n

What Are Anticholinergics?<\/strong><\/span><\/h2>\n

The term \u201canticholinergics<\/em>\u201d refers to medications, drugs, or other compounds that block the activity of the neurotransmitter <\/strong>acetylcholine<\/em><\/strong><\/a>. Generally speaking, these compounds bind to the same structures (known as receptors<\/em>) as acetylcholine throughout the body, thereby preventing this neurotransmitter from achieving its usual effects [R<\/a>, R<\/a>].<\/p>\n

Some anticholinergics, such as hyoscamine<\/em>, are derived from plants and other natural sources. For example, the fruit and leaves of the plant Atropa<\/em> Belladonna<\/em><\/a> (atropine<\/em>), sometimes also known as \u201cDeadly Nightshade,\u201d are believed to have anticholinergic effects [R<\/a>, R<\/a>].<\/p>\n

Other, \u201csynthetic<\/em>\u201d anticholinergic agents include ipratropium bromide<\/em> (Atrovent<\/em>), doxepin<\/em>, tadalafil<\/em>, diphenhydramine<\/em>, among many others. These anticholinergics are sometimes used to help treat respiratory disorders (such as asthma and bronchitis), as well as more complex health conditions, such as depression<\/a>, insomnia, irritable bowel syndrome<\/em> (IBS), and motion sickness. Some synthetic anticholinergics have also been proposed to potentially help relieve certain symptoms of Parkinson\u2019s disease and overactive bladder [R<\/a>, R<\/a>, R<\/a>, R<\/a>, R<\/a>, R<\/a>, R<\/a>].<\/p>\n

However, the use of anticholinergics also comes with certain risks \u2014 especially if taken in excess.<\/strong> These include a number of side-effects ranging from increased heart rate<\/a> (tachycardia<\/em>), elevated blood pressure (hypertension<\/em>), blurred vision, and impaired digestion, to more serious side-effects such as delirium, dementia, and even coma. They have also been reported by patients to cause skin rashes, elevated body temperature (hyperthermia<\/em>), and dryness of the mouth or skin [R<\/a>, R<\/a>].<\/p>\n

In the rest of this post, we\u2019ll review the historical and scientific background behind these anticholinergic compounds, how they work, and some of the various potential medical and other applications that have been proposed by researchers. For more information on the various potential side-effects, drug interactions, and other possible risks associated with the use of anticholinergic compounds, see part 2 of our SelfHacked series on anticholinergics here<\/a>.<\/p>\n

Mechanism of Action<\/strong><\/span><\/h3>\n

In general, the neurotransmitter acetylcholine<\/em> binds to and activates two different receptors in the body: nicotinic<\/em> and muscarinic<\/em> acetylcholine receptors.<\/p>\n

\u201cNicotinic receptors<\/em>\u201d<\/strong> got their name because they are activated by the drug nicotine<\/em><\/a>. In contrast, \u201cmuscarinic receptors<\/em>\u201d<\/strong> get their name from the fact that they are activated by a poison from mushrooms called muscarinic acid<\/em>. Anticholinergics function in the opposite way: by blocking both of these types of acetylcholine receptors [R<\/a>, R<\/a>].<\/p>\n

Acetylcholine has a wide variety of important functions throughout the body and brain. For example, it serves as the \u201cfinal messenger\u201d for the parasympathetic system<\/em>, which counteracts the \u201cfight-or-flight<\/em>\u201d response. Acetylcholine is therefore also responsible for keeping the body in a state of rest, digestion, and regeneration using the muscarinic pathway, which has five main receptor subtypes (M1-M5). Excess acetylcholine can also cause overactivation of the muscarinic system, which may contribute to inflammation in some diseases, such as in asthma. This is also why drugs that block muscarinic receptors in the lungs are used to treat these conditions, as they can help relax the airways, thus allowing for better breathing [R<\/a>].<\/p>\n

Other \u201canti-muscarinic<\/em>\u201d medications, such as those commonly used to treat overactive bladder, block specific muscarinic receptors (mostly M2 and M3). However, these medications can also sometimes cause unwanted side-effects elsewhere, such as dry mouth or headaches<\/a> [R<\/a>].<\/p>\n

Acetylcholine is also used to activate muscles using the nicotinic pathway: therefore, drugs that block this pathway can induce paralysis<\/em>, and are sometimes used during anesthesia [R<\/a>].<\/p>\n

Types of Anticholinergics<\/strong><\/span><\/h2>\n

Muscarinic Anticholinergics<\/strong><\/span><\/h3>\n

Muscarinic receptors<\/em> are located primarily within the brain and spinal cord, as well as in the muscles controlled by the parasympathetic nervous system<\/em>, including the bladder, heart, lungs, and airway muscles [R<\/a>, R<\/a>, R<\/a>].<\/p>\n

Ipratropium<\/em>, scopolamine<\/em>, and glycopyrrolate<\/em> are examples of muscarinic anticholinergics<\/em> [R<\/a>, R<\/a>, R<\/a>].<\/p>\n

Muscarinic anticholinergics are commonly used to treat bronchitis, asthma, motion sickness, and occasionally even anxiety<\/a>. Additionally, they sometimes act as \u201cantidepressants,\u201d and have also been reported to help prevent the toxic effects of certain nerve agents and other toxins [R<\/a>, R<\/a>, R<\/a>, R<\/a>].<\/p>\n

Muscarinic anticholinergics can also be referred to by different names, such as antimuscarinics<\/em>, muscarinic antagonists<\/em>, and muscarinic cholinergic antagonists<\/em>.<\/p>\n

Nicotinic<\/strong> Anticholinergics<\/span><\/h3>\n

Nicotinic receptors<\/em> are mainly located at the connections between nerves and skeletal muscles. Blocking these receptors can, therefore, interfere with movement, and \u2014 in high-enough doses \u2014 can even cause paralysis<\/em> [R<\/a>, R<\/a>].<\/p>\n

This is why curare<\/em>, a natural nicotinic anticholinergic, was historically used in hunting for centuries. Eventually, scientists began to research the physiological mechanisms of curare, and its earliest medical application was to help prevent muscle contractions during surgery. Research into curare\u2019s mechanisms eventually allowed for the development of additional synthetic alternatives, with similar activity and effects [R<\/a>, R<\/a>].<\/p>\n

Pancuronium<\/em> and mecamylamine<\/em> are examples of nicotinic receptor blockers [R<\/a>, R<\/a>].<\/p>\n

Pancuronium<\/em> is a muscle relaxant used in anesthesia. In contrast, mecamylamine<\/em> subdues the effects of alcohol, and has been used to help fight alcohol and cigarette addiction. Mecamylamine has also been reported to have some \u201cantidepressive\u201d effects [R<\/a>, R<\/a>, R<\/a>, R<\/a>].<\/p>\n

Mecamylamine was once widely used to treat elevated blood pressure (hypertension<\/em>). However, that is rarely the case now, due to the high rate of side-effects caused by the required dosage [R<\/a>].<\/p>\n

Nicotinic anticholinergics can also be referred to as antinicotinic<\/em> or nicotinic antagonists<\/em>.<\/p>\n

14 Potential Uses of Anticholinergics<\/span><\/h2>\n

In the sections below, we\u2019ll discuss a variety of different proposed medical or therapeutic applications for anticholinergic compounds and drugs, and what the latest science has to say about them.<\/p>\n

Before we begin, however, it is important to note that not all of these drugs have been officially approved for each application or specific medical condition discussed in the sections below. Additionally, many of the drugs we discuss in the sections below require a prescription and oversight from a medical professional to be taken safely and legally.<\/strong><\/p>\n

Therefore, if you have any of the following health conditions \u2014 or if you have any other relevant questions about these potential applications of anticholinergics \u2014 then we strongly recommend discussing them thoroughly with your doctor, who can help further inform you about any potential therapeutic benefits or risks associated with any particular course of treatment. The information in this post should not otherwise be used as a replacement for conventional medical care or treatment<\/strong>, as only a fully-qualified medical professional has the necessary background and training to devise a treatment plan that is fully-suited to your individual medical history and needs.<\/p>\n

Relatedly, it should be kept in mind that many of the potential applications below have been proposed on the basis of scientific evidence that is still in a relatively early stage<\/strong>. For example, much of this preliminary research comes from studies in animals and cell cultures, rather than full clinical trials in human patients. Therefore, the uses outlined below should be considered to currently have \u201cinsufficient evidence\u201d until significant amounts of additional research is performed<\/strong> \u2014 especially from studies in large samples of human users.<\/p>\n

With all that in mind, let\u2019s see what some of the latest science has to say about the potential uses of anticholinergic compounds, as well as the potential mechanisms responsible for their effects!<\/p>\n

1) Respiratory Diseases and Conditions<\/span><\/h3>\n

\"Anticholinergics<\/strong><\/p>\n