Beta 2 Receptor Agonists Overview

Medicines that help to loosen mucus in the airways so it can be coughed up more easily.

A class of drugs that increase urine output by reducing sodium and water reabsorption in the kidneys.

Beta 2 Receptor Agonists bind to β2 smooth muscle cells in the airway. They stimulate smooth muscle cell relaxation, causing bronchodilation via the cyclic AMP pathway. They inhibit release of hypersensitivity mediators.

A type of diuretic that acts on the ascending loop of Henle in the kidneys, increasing urine output and potassium excretion.

Short-acting beta agonists (SABAs) are effective for 4-6 hours and include Albuterol, Levalbuterol, Pirbuterol, and Tirbutaline.

A group of diuretics that act on the distal convoluted tubule of the kidneys, increasing urine output and potassium excretion.

Long-acting beta agonists (LABAs) are effective for 12 hours and include Salmeterol, Fomoterol, and Arfomoterol.

A class of diuretics that block the action of aldosterone in the kidneys, leading to potassium retention and a weaker diuretic effect.

Ultra-long acting beta agonists (ULABAs) are effective for 24 hours and include Indacaterol, Olodaterol, Vilanterol.

A laxative that works by stimulating the muscles in the intestines to increase peristalsis.

Laxatives that work by drawing water into the intestines, increasing stool volume and softening.

Inhaled anticholinergics work by blocking muscarinic cholinergic receptors, decreasing formation of cyclic GMP, and ultimately reducing contractility of lung smooth muscle.

Short-acting muscarinic antagonists (SAMAs) are effective for 4-6 hours and include Ipratropium bromide.

Laxatives that increase stool bulk by absorbing water in the intestines.

Laxatives that lubricate the stool, making it easier to pass.

Long-acting muscarinic antagonists (LAMAs) are effective for 12-24 hours and include Tiotroprium bromide, Aclidinium bromide, Umeclidinium bromide, and Revefenacin.

Laxatives that work by softening the stool by mixing lipids and water.

Glycopyrronium bromide is a long-acting muscarinic antagonist that preferentially binds to M3 receptors, which are involved in bronchoconstriction in COPD (Chronic Obstructive Pulmonary Disease).

Methylxanthines like theophylline inhibit phosphodiesterases, leading to an increase in cyclic AMP. This promotes bronchial and pulmonary vessel relaxation.

Laxatives that work by drawing water into the intestines, increasing stool volume and softening.

Inhaled corticosteroids inhibit IgE and mast cell mediated migration of inflammatory cells into bronchial mucosa, thus reducing late-phase allergic reactions.

A type of laxative that works by activating chloride channels in the intestinal epithelium, leading to increased chloride secretion and softer stool.

Most inhaled corticosteroids come in multiple forms and delivery systems, and they are rapidly absorbed from the lungs and gastrointestinal tract.

Laxatives that work by blocking opioid receptors in the gut, increasing peristalsis and reducing constipation.

Leukotrienes are inflammatory mediators produced by eosinophils and mast cells. Leukotriene receptor agonists like montelukast block the action of LTD4, while 5-lipoxygenase pathway inhibitors like zileuton inhibit the formation of leukotrienes.

Drugs that help to control diarrhea by absorbing excess fluid and binding to the stool.

Drugs that slow down intestinal motility and reduce the secretion of fluids, reducing diarrhea.

Antihistamines block the action of histamine by binding to H1 receptors this reduces respiratory, vascular, and GI smooth muscle constriction, as well as capillary permeability.

First-generation antihistamines like diphenhydramine, chlorpheniramine, and hydroxyzine bind non-selectively to central H1 receptors and can cause sedation.

Second-generation antihistamines like cetirizine, levocetirizine, loratadine, desloratadine, and fexofenadine are selective for peripheral H1 receptors, leading to less sedation.

H2RAs block the histamine-2 receptor on gastric parietal cells, decreasing HCl production and increasing gastric juice pH towards alkalinity.

Cimetidine, a common H2RA, can cause gynecomastia and erectile dysfunction due to its antiandrogenic properties. These effects are less common with other H2RAs.

H2RAs have various effects on gastric secretions, emptying speed, LES pressure, and gastrin levels. However, famotidine is most potent at lowering gastric acid secretion.

H2RAs are not anticholinergic, meaning they don't block histamine-1 receptors. They are not well-studied in pregnancy and should be used with caution during lactation.

Metoclopramide is used primarily for gastroparesis due to its prokinetic properties. It's not a first-line GERD treatment because it can cause extrapyramidal symptoms (EPS).

Bethanechol is used primarily for gastroparesis, not GERD, and has prokinetic properties. Like Metoclopramide, it's not a first-line treatment.

Antacids help improve LES tone by neutralizing stomach acid, which indirectly increases LES pressure.

PPIs are the preferred antisecretory medications for PUD treatment due to their superior gastric acid suppression compared to H2RAs.

The primary goal of PUD treatment is to eliminate H. Pylori infection, reduce or eliminate symptoms, and heal ulcer lesions.

PUD treatment aims to prevent complications like bleeding, perforation, and carcinoma, as well as to prevent the recurrence of ulcers.

A type of diarrhea drug that is used to treat diarrhea caused by Irritable Bowel Syndrome (IBS) and other conditions. It is a type of opioid that works by slowing down the movement of the intestines.

A type of drug used for chronic diarrhea in patients with IBS. It is a mu and kappa opioid receptor agonist and delta opioid receptor antagonist. It can be dangerous for specific patient groups with conditions like biliary disorders, pancreatitis, or severe liver impairment.

A type of drug that is used to treat diarrhea-predominant Irritable Bowel Syndrome (IBS) in women who don't respond to other treatments. It's a selective 5-HT3 receptor antagonist, which means it focuses on specific receptors in the GI tract to decrease movement and secretions.

A type of drug used to treat nausea and vomiting. These antiemetics can be used for motion sickness or to prevent vomiting in patients receiving chemotherapy.

A type of antiemetic that includes drugs like dimenhydrinate, diphenhydramine, hydroxyzine, and meclizine. These are often used to treat motion sickness due to their effect on the central nervous system, especially in the vestibulocerebellar areas.

A type of antiemetic that includes drugs like prochlorperazine, perphenazine, and promethazine. These work primarily by blocking dopamine receptors in the chemoreceptor trigger zone (CTZ) in the brain, which helps to reduce nausea and vomiting.

A type of drug used to treat chemotherapy-induced nausea and vomiting when other drugs have failed. Dronabinol is also used to stimulate appetite in some patients.

A type of antiemetic that works by blocking serotonin receptors in the brain and the gut. This helps to prevent the release of serotonin, which can trigger nausea and vomiting especially due to chemotherapy.

A type of antiemetic that's often used to prevent motion sickness. It works by blocking the action of acetylcholine in the brain.

A type of antiemetic that blocks substance P, a chemical messenger in the central nervous system, which is involved in nausea and vomiting.

A miscellaneous antiemetic that works by blocking dopamine receptors in the chemoreceptor trigger zone (CTZ), similar to phenothiazines. It's used for treating nausea and vomiting.

A class of drugs used to treat various gastrointestinal conditions, such as diarrhea, constipation, and nausea and vomiting. They work by targeting different receptors and mechanisms in the gastrointestinal tract.

Diphenoxylate and Difenoxin are opioids used to treat diarrhea. They have anticholinergic effects, which can cause sedation and other side effects. They are not recommended for use in children, especially those with Down syndrome, due to these risks.

Antidiarrheal medications can worsen certain conditions, such as intestinal infections. They can mask the symptoms and delay diagnosis, making it difficult to identify and treat the underlying cause.

Phenothiazines are a class of drugs that can cause various side effects, including extrapyramidal symptoms (EPS), sedation, respiratory depression, and agranulocytosis. These effects are more likely with long-term use and can be problematic in certain patient populations.

Prevent or reduce symptoms, heal esophageal damage (esophagitis), prevent serious complications like esophageal cancer, and prevent recurring symptoms.

Avoid foods and drinks that trigger symptoms, don't overeat, avoid bending over and strenuous exercise for 3 hours after eating, avoid lying flat for 3 hours after eating, elevate the head of the bed during sleep, lose weight if overweight, and quit smoking.

Antacids are used for occasional relief of GERD symptoms, often along with other acid-suppressing drugs. They work by neutralizing stomach acid.

Proton pump inhibitors (PPIs) are the first-line treatment for most GERD cases, especially if symptoms are frequent or there's esophagitis. They block the enzyme that produces stomach acid.

Histamine-2 receptor antagonists (H2RAs) are another class of drugs for GERD, but PPIs are preferred in most cases. They work by blocking histamine receptors that stimulate acid production.

These drugs are used along with acid-suppressing medications, to help improve the function of the lower esophageal sphincter (LES), which prevents acid from flowing back into the esophagus.

Prokinetic agents are used when GERD symptoms persist despite maximal acid suppression and lifestyle changes. They help to speed up the movement of food through the digestive system.

Most commonly used for PUD (Peptic Ulcer Disease), they protect the stomach lining from damage caused by acid and pepsin.

Constipation can occur with aluminum- and calcium-based antacids, while diarrhea is a common side effect of magnesium-based antacids. Antacids can also cause alkalosis in patients with kidney failure.

Antacids are not the main treatment for severe GERD, but can be used along with stronger medications. They shouldn't be used if the cause of gastrointestinal symptoms is unclear.

PPIs are very effective at reducing stomach acid production, which can lead to a lack of acid (achlorhydria) in some cases. This can cause a range of side effects, including changes in nutrient absorption.

Long-term use of PPIs can be associated with several problems, such as nutrient deficiencies, increased risk of bone fractures, kidney issues, infections, and potentially even an increased risk of cancer and dementia. However, more research is needed for most of these associations.

PPIs are not recommended for people with known allergies, and usage should be cautious in individuals with liver problems, older adults, pregnant women, and breastfeeding mothers. They are generally safe for children, but should be used with careful monitoring.

PPIs are a powerful treatment for GERD, but they must be combined with lifestyle changes. If the GERD isn't improving, check that the patient is taking the medication as prescribed and following lifestyle recommendations.

H2RAs are primarily used as backup when PPIs aren't working or aren't appropriate, and are particularly useful for treating GERD with or without esophagitis, PUD, and hypersecretory states. Ranitidine (Zantac) is no longer available in the United States.