Beta 2 Receptor Agonists Overview

These medications bind to beta 2 receptors in airway smooth muscle cells, triggering relaxation and bronchodilation by stimulating cyclic AMP. They also inhibit the release of hypersensitivity mediators, particularly from mast cells.

Beta 2 agonists can cause side effects like tachycardia and tremors due to their partial activity on beta 1 receptors.

SABA medications like Albuterol, Levalbuterol, and Pirbuterol provide rapid relief from bronchospasm for 4-6 hours.

LABA medications like Salmeterol and Formoterol offer sustained bronchodilation for 12 hours.

These drugs block muscarinic cholinergic receptors, preventing acetylcholine from binding and decreasing cyclic GMP levels. This reduces smooth muscle contraction in the lungs.

Common side effects of inhaled anticholinergics include dry mouth, cough, and headache.

SAMA medications, such as Ipratropium bromide, provide relief from bronchospasm for 4-6 hours.

LAMA medications like Tiotropium bromide and Aclidinium bromide provide long-term bronchodilation for 12-24 hours.

These medications work by activating beta 2 receptors in the airways, causing smooth muscle relaxation and bronchodilation. This happens via the cyclic AMP pathway and helps open up the airways.

These medications target beta 2 receptors in airway smooth muscle cells, causing relaxation and bronchodilation by stimulating cyclic AMP. They also prevent the release of hypersensitivity mediators.

Beta 2 agonists can cause side effects such as tachycardia (fast heart rate) and tremors due to their partial activity on beta 1 receptors.

Short-acting beta agonists (SABAs) provide quick relief from bronchospasm for 4-6 hours.

Albuterol (Proair, Ventolin, Proventil) is a common SABA.

Long-acting beta agonists (LABAs) provide sustained bronchodilation for 12 hours.

Salmeterol (Serevent) is a well-known LABA.

These drugs block muscarinic cholinergic receptors in the lungs, preventing acetylcholine from binding and decreasing cyclic GMP levels. This reduces smooth muscle contraction and helps keep airways open.

Common side effects include dry mouth, cough, and headache.

Short-acting muscarinic antagonists (SAMAs) provide short-term relief from bronchospasm for 4-6 hours.

Ipratropium bromide (Atrovent) is a popular SAMA.

Long-acting muscarinic antagonists (LAMAs) provide long-term bronchodilation for 12-24 hours.

Tiotropium bromide (Spiriva) is a well-known LAMA.

Methylxanthines like theophylline work by inhibiting phosphodiesterases, leading to an increase in cyclic AMP. This results in bronchial and pulmonary vessel relaxation.

Common side effects include headache, irritability, gastric irritation, nausea, and vomiting.

Medicines that help loosen mucus in the airways, making it easier to cough up.

Not recommended for coughs caused by asthma, COPD, heart failure, or ACE inhibitor therapy due to potential complications.

Diuretics primarily work by increasing urine production, helping eliminate excess water and sodium from the body.

Diuretics reduce blood pressure by decreasing blood volume and lowering resistance in blood vessels.

Diuretics are categorized into several classes based on their site of action and mechanisms: carbonic anhydrase inhibitors, osmotic diuretics, aldosterone antagonists, loop diuretics, and thiazide diuretics.

Common side effects include electrolyte imbalances (like low potassium), elevated uric acid, and glucose intolerance.

Diuretics can cause low potassium (hypokalemia), which may lead to complications like muscle weakness and irregular heartbeat.

Loop diuretics work by blocking sodium reabsorption in the loop of Henle, causing more sodium and water to be excreted in urine.

Thiazide diuretics block sodium reabsorption in the distal renal tubule, causing less sodium to be reabsorbed back into the body.

Aldosterone antagonists block the action of the hormone aldosterone, which helps to conserve sodium and water. This results in increased sodium and water excretion.

There are many types of laxatives, including stimulants, osmotics, bulk-producing, lubricants, surfactants, hyperosmolar, chloride channel activators, and opioid receptor antagonists.

Excessive laxative use can lead to electrolyte imbalances, fluid depletion, and other complications, potentially causing dependency.

Common antidiarrheals include absorbent drugs (kaolin and pectin, bismuth subsalicylate) and opiates (diphenoxylate with atropine, difenoxin with atropine, loperamide).

Be cautious using bismuth subsalicylate in fevers, especially in children, due to the potential for Reye's syndrome.

H2RAs block histamine-2 receptors on gastric parietal cells, decreasing HCl production and raising gastric juice pH towards alkaline.

H2RAs can cause adverse effects like gynecomastia, erectile dysfunction (cimetidine), cardiac rhythm abnormalities, CNS alterations, hematologic issues, GI problems, vitamin B12 deficiency, immune-related issues, and fever.

H2RAs are not well studied in pregnancy, so their use should be carefully considered and weighed against the potential risks. Their use in lactation is also discouraged.

Metoclopramide is used for lower-tier GERD treatment and gastroparesis, primarily due to its prokinetic properties. However, its use is limited by its serious adverse effects (EPS).

Bethanechol is used for lower-tier GERD treatment and gastroparesis, primarily due to its prokinetic properties. It is not used as monotherapy.

Antacids improve lower esophageal sphincter (LES) tone and increase gastric pH, helping reduce symptoms of GERD.

PUD treatment aims to eliminate Helicobacter pylori, reduce or eliminate symptoms, heal ulcer lesions, prevent complications, and prevent recurrent disease.

PPIs are the primary drugs used for PUD treatment due to their superior ability to suppress gastric acid secretion, compared to H2RAs.

Eliminating Helicobacter pylori is a crucial goal of PUD therapy because it is the main cause of the disease.

PPIs are much more effective at suppressing gastric acid secretion than H2RAs, making them the preferred choice for PUD treatment.

The main aims of GERD treatment are to reduce or stop symptoms, heal any esophageal damage, prevent complications like cancer, and avoid recurring symptoms.

To manage GERD, avoid triggering foods, don't overeat, wait 3 hours after eating before bending or exercising, elevate your head while sleeping, and aim for a healthy weight.

Antacids neutralize stomach acid by reacting with it, forming salt and water. They also inhibit pepsin activity and can help improve lower esophageal sphincter (LES) tone.

Aluminum and calcium-based antacids can cause constipation, while magnesium-based antacids can cause diarrhea.

PPIs block the enzyme responsible for producing stomach acid, resulting in significantly reduced acid secretion.

PPIs can cause GI symptoms like nausea, pain, gas, or constipation/diarrhea. They can also cause dizziness and drowsiness.

Long-term PPI use may lead to nutrient deficiencies, risk of fractures, kidney problems, infections, possible gastric cancer risk, and potential link to dementia and increased mortality.

H2RAs block histamine receptors in the stomach, reducing acid production, but not as effectively as PPIs.

These drugs help move food faster through the digestive tract, but have serious side effects, so they are only used after other therapies have failed.

Antacids should not be the sole treatment for significant GERD or frequent symptoms. They should be used with an acid-suppressing medication, not in the setting of unknown abdominal pain, and not in certain medical conditions.

PPIs are contraindicated in some cases, need caution for liver issues and older patients, and are not recommended during pregnancy unless essential.

Treating GERD involves not only medication, but also continuous lifestyle changes, regular monitoring of symptoms, and adjustment of therapy as needed.

GERD treatment is often a combination of lifestyle changes, medication, and monitoring. The choice of medication depends on severity of symptoms, presence of complications, individual tolerability, and potential risks.

These medications are opioid-like drugs used to treat diarrhea. They work by slowing down the movement of the intestines, giving more time for water and electrolytes to be absorbed back into the body.

Similar to diphenoxylate and difenoxin, loperamide is an opioid-like medication primarily used for treating acute diarrhea. It mainly interacts with receptors in the intestines and has less effect on the central nervous system, reducing the risk of sedation.

Eluxadoline is used for treating chronic diarrhea predominantly in irritable bowel syndrome (IBS). It works by activating mu and kappa opioid receptors, which inhibits intestinal motility, and blocking delta opioid receptors, which reduces pain.

Alosetron is a selective 5-HT3 receptor antagonist primarily used for women with severe diarrhea-predominant IBS that hasn't responded to other treatments. Its main effect is decreasing intestinal motility and secretions, helping to reduce both diarrhea and pain.

These are antihistamine medications commonly used for motion sickness and nausea and vomiting caused by inner ear problems (vertigo). They primarily work by blocking histamine receptors and reducing central nervous system activity.

Phenothiazines are another class of drugs used for preventing and treating nausea and vomiting. They work by blocking dopamine receptors in the chemoreceptor trigger zone (CTZ) in the brain, which is responsible for triggering the vomiting reflex.

Dronabinol is a cannabinoid medication used to treat nausea and vomiting caused by chemotherapy. It also helps to stimulate appetite in people with weight loss due to illnesses such as cancer.

These are 5-HT3 receptor antagonists commonly prescribed to prevent nausea and vomiting associated with chemotherapy. They work by blocking serotonin receptors in the brain and gut, preventing the side effect of chemotherapy.

Scopolamine is an anticholinergic medication primarily used for preventing motion sickness. It works by blocking acetylcholine receptors in the brain and nervous system, reducing signals related to motion sickness.

Aprepitant is a Substance P/neurokinin 1 (NK1) receptor antagonist used to prevent chemotherapy-induced nausea and vomiting, often in combination with other antiemetics.

Trimethobenzamide is a miscellaneous antiemetic used to treat nausea and vomiting. It primarily works by blocking dopamine receptors in the CTZ, similar to phenothiazines.

Antihistamines are effective in treating motion sickness due to their ability to reduce signals from the inner ear to the brain. This calming effect on the nervous system helps alleviate the dizziness and nausea associated with motion sickness.

While effective for nausea and vomiting, phenothiazines can cause a multitude of side effects, including: extrapyramidal symptoms (EPS) especially in children, sedation, respiratory depression, and even agranulocytosis with long-term use.

Cannabinoids, like dronabinol, can have various side effects, including mood changes, hallucinations, memory problems, seizures, and cardiovascular effects like palpitations, tachycardia, and hypotension.

5-HT3 antagonists can mask the symptoms of ileus, making a potentially serious condition harder to diagnose. Also, some formulations contain aspartame, which should be avoided by individuals with phenylketonuria (PKU).