Respiratory+&+Gastrointestinal+Drugs

 Ashley, Lauren, & Yelena = =  Chapters 32 & 33  **DRUGS ****ACTING ON THE RESPIRATORY SYSTEM ** **COPD- is the chronic progressive disease characterized by ****irreversible airflow limitation. Cigarette smoking is a major cause of COPD. ****Symptoms include: chronic cough with sputum, and breathlessness on exertion. ****Chronic bronchitis, emphysema and small airway disease are present in patients ****with COPD in variable degrees. ** **A ****sthma is a chronic inflammatory disease of the airways associated ****with acute symptoms, exacerbations, and airway remodeling. The bronchospazm and ****wheezing can be reversed by bronchodilators; exacerbation and airway remodeling ****<span style="background-color: transparent; color: #000000; font-size: 16px; text-align: left; text-decoration: none; vertical-align: baseline;">are caused by chronic inflammation and can be controlled with anti-inflammatory ****<span style="background-color: transparent; color: #000000; font-size: 16px; text-align: left; text-decoration: none; vertical-align: baseline;">drugs. ** <span style="background-color: transparent; color: #000000; display: block; font-family: Times New Roman; font-size: 16px; text-align: left; text-decoration: none; vertical-align: baseline;">**﻿** <span style="background-color: transparent; color: #000000; display: block; font-family: Times New Roman; font-size: 16px; text-align: left; text-decoration: none; vertical-align: baseline;">**<span style="background-color: transparent; color: #000000; font-size: 16px; text-align: left; text-decoration: none; vertical-align: baseline;">Corticosteriods ** <span style="background-color: transparent; color: #000000; display: block; font-family: Times New Roman; font-size: 16px; text-align: left; text-decoration: none; vertical-align: baseline;">**<span style="background-color: transparent; color: #000000; font-size: 16px; text-align: left; text-decoration: none; vertical-align: baseline;">Beta ****<span style="background-color: transparent; color: #000000; font-size: 16px; text-align: left; text-decoration: none; vertical-align: baseline;">2-Adrenergic Receptor Agonist ** <span style="background-color: transparent; color: #000000; display: block; font-family: Times New Roman; font-size: 16px; text-align: left; text-decoration: none; vertical-align: baseline;">**<span style="background-color: transparent; color: #000000; font-size: 16px; text-align: left; text-decoration: none; vertical-align: baseline;">Specific ****<span style="background-color: transparent; color: #000000; font-size: 16px; text-align: left; text-decoration: none; vertical-align: baseline;">Agents- ** > effects > Nonbronchodilating, nonsteroidal drug used for prophylactic treatment > of asthma. Administered through inhalation and > causes smooth muscle relaxation. Mechanism of action is not fully > understood, but it inhibits the release of mediators from mast cells and > other inflammatory cells. Inhibits early & late asthmatic responses > & is effective in long-term treatment of chronic asthma. > various diseases. It is used as an adjuvant for the severe treatment of > glucocorticoid-dependant asthma, has an anti-inflammatory action. <span style="background-color: transparent; color: #000000; display: block; font-family: Times New Roman; font-size: 16px; text-align: left; text-decoration: none; vertical-align: baseline;">**<span style="background-color: transparent; color: #000000; font-size: 16px; text-align: left; text-decoration: none; vertical-align: baseline;">__Pharmacotherapy__ ** **__ for COPD- __** <span style="background-color: transparent; color: #000000; display: block; font-family: Times New Roman; font-size: 16px; text-align: left; text-decoration: none; vertical-align: baseline;"> there is no cure for COPD, the goals of therapy are to prevent disease <span style="background-color: transparent; color: #000000; display: block; font-family: Times New Roman; font-size: 16px; text-align: left; text-decoration: none; vertical-align: baseline;"> progression, relieve symptoms, improve health status, prevent excacerbations,  <span style="background-color: transparent; color: #000000; display: block; font-family: Times New Roman; font-size: 16px; text-align: left; text-decoration: none; vertical-align: baseline;"> reduce morbidity, and minimize adverse effects from the treament. <span style="background-color: transparent; color: #000000; display: block; font-family: Times New Roman; font-size: 16px; text-align: left; text-decoration: none; vertical-align: baseline;"> Anticholinergics and B2 adrenergic recepyor agonists causes bronchodilation <span style="background-color: transparent; color: #000000; display: block; font-family: Times New Roman; font-size: 16px; text-align: left; text-decoration: none; vertical-align: baseline;"> through different mechanisms. Drug therapy was combined with smoking cessation <span style="background-color: transparent; color: #000000; display: block; font-family: Times New Roman; font-size: 16px; text-align: left; text-decoration: none; vertical-align: baseline;"> and pulmonary rehabilitation exercises. <span style="background-color: transparent; color: #000000; display: block; font-family: Times New Roman; font-size: 16px; text-align: left; text-decoration: none; vertical-align: baseline;">**<span style="background-color: transparent; color: #000000; font-size: 16px; text-align: left; text-decoration: none; vertical-align: baseline;">__Drugs__ **** __for Mild Respiratory Illness-__ ** Drugs used to provide symptomatic relief of respiratory infection or mild allergies with respiratory symptoms.
 * <span style="background-color: transparent; color: #000000; display: block; font-family: Times New Roman; font-size: 16px; text-align: left; text-decoration: none; vertical-align: baseline;"> Mechanism of Action: diffuses rapidly across plasma membrane; bind to the receptor; receptor-steroid complex is transported to the nucleus where it binds to DNA and represses the genes that are activated in inflammatory disease.
 * <span style="background-color: transparent; color: #000000; display: block; font-family: Times New Roman; font-size: 16px; text-align: left; text-decoration: none; vertical-align: baseline;"> Pharmacologic Effects: corticosteroids are very effective in controlling the symptoms of the inflammatory lung disease but they don’t cure the disease. In asthma, corticosteroids reduce inflammation and hyper responsiveness of the tissue, improve the lung function, and decrease the severity of the asthma attacks. The treatment of COPD with corticosteroids is controversial.
 * <span style="background-color: transparent; color: #000000; display: block; font-family: Times New Roman; font-size: 16px; text-align: left; text-decoration: none; vertical-align: baseline;"> Efficacy & Safety: The optimal rout of administration is inhalation- it delivers the drug directly to the lungs. Corticosteroids act locally when they are inhaled, this reduce their systematic adverse effects encountered with oral and parenteral administration.
 * <span style="background-color: transparent; color: #000000; display: block; font-family: Times New Roman; font-size: 16px; text-align: left; text-decoration: none; vertical-align: baseline;"> Adverse Effects: the most common are oropharengeal candidacies and dysphonia. Less common are adrenal suppression, bone loss,
 * <span style="background-color: transparent; color: #000000; display: block; font-family: Times New Roman; font-size: 16px; text-align: left; text-decoration: none; vertical-align: baseline;"> behavioral changes, metabolic changes, weight gain.
 * <span style="background-color: transparent; color: #000000; display: block; font-family: Times New Roman; font-size: 16px; text-align: left; text-decoration: none; vertical-align: baseline;"> Mechanism of Action: Beta 2-Adrenergic receptor agonists reduce Ca availability in the cell that cause passive relaxations of the smooth muscle of the airways.
 * <span style="background-color: transparent; color: #000000; display: block; font-family: Times New Roman; font-size: 16px; text-align: left; text-decoration: none; vertical-align: baseline;"> Pharmacologic Effects: bronchodialation, reduction of inflammatory cytokines productions, suppression of plasma exudates, regulation of fluid balance in the alveolar epithelial cells.
 * <span style="background-color: transparent; color: #000000; display: block; font-family: Times New Roman; font-size: 16px; text-align: left; text-decoration: none; vertical-align: baseline;"> Adverse Effects: increase in sensitivity of the smooth muscle in lungs to the noxious stimuli.
 * <span style="background-color: transparent; color: #000000; display: block; font-family: Times New Roman; font-size: 16px; text-align: left; text-decoration: none; vertical-align: baseline;"> Albuterol: most commonly prescribed beta2 adrenergic bronchodialator. it is available in tablet form and aerosol.
 * <span style="background-color: transparent; color: #000000; display: block; font-family: Times New Roman; font-size: 16px; text-align: left; text-decoration: none; vertical-align: baseline;"> Salmeterol: long-acting, highly selective B2-Adrenergic agent. Provides bronchodilation for at least 12 hours. Has a slow onset, not for relief of acute asthma.
 * <span style="background-color: transparent; color: #000000; display: block; font-family: Times New Roman; font-size: 16px; text-align: left; text-decoration: none; vertical-align: baseline;"> Terbutaline: Long duration of action, provides the greatest protection against bronchoconstriction in patients with spontaneous asthma.
 * <span style="background-color: transparent; color: #000000; display: block; font-family: Times New Roman; font-size: 16px; text-align: left; text-decoration: none; vertical-align: baseline;">**<span style="background-color: transparent; color: #000000; font-size: 16px; text-align: left; text-decoration: none; vertical-align: baseline;">Interaction ****<span style="background-color: transparent; color: #000000; font-size: 16px; text-align: left; text-decoration: none; vertical-align: baseline;">between corticosteroids & beta2-adrenergin receptor agonists- ** Corticosteroids & beta2 agonists have different mechanisms of action & in patients with asthma or COPD, coadministration of the two classes of drugs results in a synergistic effect as each drug enhances the activity of the other.
 * <span style="background-color: transparent; color: #000000; display: block; font-family: Times New Roman; font-size: 16px; text-align: left; text-decoration: none; vertical-align: baseline;">**<span style="background-color: transparent; color: #000000; font-size: 16px; text-align: left; text-decoration: none; vertical-align: baseline;">Other Adrenergic ****<span style="background-color: transparent; color: #000000; font-size: 16px; text-align: left; text-decoration: none; vertical-align: baseline;">Receptor Agonists **
 * <span style="background-color: transparent; color: #000000; display: block; font-family: Times New Roman; font-size: 16px; text-align: left; text-decoration: none; vertical-align: baseline;"> Epinephrine- Adrenergic receptor agonist, short acting oral inhalations. Parenteral epinephrine is used for acute episodes of asthma requiring immediate relief. Can also improve respiration by relieving congestion ofthe bronchial mucosa.
 * <span style="background-color: transparent; color: #000000; display: block; font-family: Times New Roman; font-size: 16px; text-align: left; text-decoration: none; vertical-align: baseline;"> Ephedrine- Stimulates B-adrenergic and a-adrenergic receptors. Long duration of action administered at bedtime to prevent nocturnal wheezing.
 * <span style="background-color: transparent; color: #000000; display: block; font-family: Times New Roman; font-size: 16px; text-align: left; text-decoration: none; vertical-align: baseline;">**<span style="background-color: transparent; color: #000000; font-size: 16px; text-align: left; text-decoration: none; vertical-align: baseline;">Theophylline- ** Naturally occurring plant alkaloid. Used for Bronchodilation and anti-inflammatory
 * <span style="background-color: transparent; color: #000000; display: block; font-family: Times New Roman; font-size: 16px; text-align: left; text-decoration: none; vertical-align: baseline;">**<span style="background-color: transparent; color: #000000; font-size: 16px; text-align: left; text-decoration: none; vertical-align: baseline;">Cromolyn- ** Long-term treatment of chronic asthma.
 * <span style="background-color: transparent; color: #000000; display: block; font-family: Times New Roman; font-size: 16px; text-align: left; text-decoration: none; vertical-align: baseline;">**<span style="background-color: transparent; color: #000000; font-size: 16px; text-align: left; text-decoration: none; vertical-align: baseline;">Methotrexate- ** well-known immunosuppressant chemotherapeutic drug used to treat
 * <span style="background-color: transparent; color: #000000; display: block; font-family: Times New Roman; font-size: 16px; text-align: left; text-decoration: none; vertical-align: baseline;">**<span style="background-color: transparent; color: #000000; font-size: 16px; text-align: left; text-decoration: none; vertical-align: baseline;">Antitussives ** - an ideal antitussive agent should decrease the frequency and intensity of coughing but still alow adequate elimination of excessive secretions from the respiratory tract.
 * <span style="background-color: transparent; color: #000000; display: block; font-family: Times New Roman; font-size: 16px; text-align: left; text-decoration: none; vertical-align: baseline;">**<span style="background-color: transparent; color: #000000; font-size: 16px; text-align: left; text-decoration: none; vertical-align: baseline;">Opioid Analgesics ** : suppress cough. Codeine is the most useful opiod for cough suppression acting centrally on the medullary cough center. over dosage can result in respiratory depression, convulsions, hypotension, and tachycardia.
 * <span style="background-color: transparent; color: #000000; display: block; font-family: Times New Roman; font-size: 16px; text-align: left; text-decoration: none; vertical-align: baseline;">**<span style="background-color: transparent; color: #000000; font-size: 16px; text-align: left; text-decoration: none; vertical-align: baseline;">Other drugs for cough ** : other drugs that acts centrally on the on the medullary cough center include benzonatate, extromethorphan, and noscapaine.
 * <span style="background-color: transparent; color: #000000; display: block; font-family: Times New Roman; font-size: 16px; text-align: left; text-decoration: none; vertical-align: baseline;">**<span style="background-color: transparent; color: #000000; font-size: 16px; text-align: left; text-decoration: none; vertical-align: baseline;">Nasal Decongestants- ** most common are adrenergic agents (phenylephrine, ephedrine,propylhexedrine, and oxymetazoline). These drugs act b y stimulating excitatory a-adrenergic receptors of vascular smooth muscles by constricting the dilated arterioles within the nasal mucosa. The constriction reduces blood flow in the edematous area and opens obstructed nasal passages. Most of the drugs are used topically and may cause temporary stinging, burning or drying of the mucosa.
 * <span style="background-color: transparent; color: #000000; display: block; font-family: Times New Roman; font-size: 16px; text-align: left; text-decoration: none; vertical-align: baseline;">**<span style="background-color: transparent; color: #000000; font-size: 16px; text-align: left; text-decoration: none; vertical-align: baseline;">Intranasal Steroids- ** adrenal corticosteroids administered by nasal spray are effective for the relief of seasonal and perennial rhinitis. Therapeutic benefits begin after several days of use. When they are used appropriately systemic effects are minimal. Local candidiasis of the mouth and pharynx has been reported. Rinsing the mouth after may prevent this from occurring.
 * <span style="background-color: transparent; color: #000000; display: block; font-family: Times New Roman; font-size: 16px; text-align: left; text-decoration: none; vertical-align: baseline;">**<span style="background-color: transparent; color: #000000; font-size: 16px; text-align: left; text-decoration: none; vertical-align: baseline;">Expectorants & Mucolytics- ** agents used to stimulate the flow of the respiratory tract secretions are termed expectorants.
 * <span style="background-color: transparent; color: #000000; display: block; font-family: Times New Roman; font-size: 16px; text-align: left; text-decoration: none; vertical-align: baseline;"> Mucolytic agents are used to reduce the viscosity of respiratory tract secretions. Both drugs enhance the movement of secretions upward and outward by cilliary movement and coughing. Expectorants are believed to act by stimulating receptors in the gastric mucosa, initiating reflex secretion of respiratory tract fluid. This action is thought to increase the volume and decrease the viscosity of the secretions. There is little clinical evidence supporting the efficacy of these agents.

<span style="background-color: transparent; color: #000000; display: block; font-family: Times New Roman; font-size: 16px; text-align: center; text-decoration: none; vertical-align: baseline;"> **<span style="background-color: transparent; color: #00b0f0; font-size: 16px; text-align: center; text-decoration: none; vertical-align: baseline;">DRUGS ACTING ON THE ****<span style="background-color: transparent; color: #00b0f0; font-size: 16px; text-align: center; text-decoration: none; vertical-align: baseline;">GASTROINTESTINAL TRACT ** <span style="background-color: transparent; color: #000000; display: block; font-family: Times New Roman; font-size: 16px; text-align: center; text-decoration: none; vertical-align: baseline;"> **﻿** <span style="background-color: transparent; color: #000000; display: block; font-family: Times New Roman; font-size: 16px; text-align: left; text-decoration: none; vertical-align: baseline;"> Acid peptic conditions such as heartburn, indigestion, gastroesophageal reflex and peptic ulcer disease, are often treated with drugs that either reduce intragastric acidityor promote gastrointestinal mucosal defense. In all these conditions, patient discomfort primarily results from the caustic effects of the gastric acid on the esophagus or from overcoming the gastrointestinal mucosal defense system or both.

<span style="background-color: transparent; color: #000000; display: block; font-family: Times New Roman; font-size: 16px; text-align: left; text-decoration: none; vertical-align: baseline;">**<span style="background-color: transparent; color: #000000; font-size: 16px; text-align: left; text-decoration: none; vertical-align: baseline;">__Drugs used to reduce__ **** __gastric acid & treat peptic ulcer disease__ ** <span style="background-color: transparent; color: #000000; display: block; font-family: Times New Roman; font-size: 16px; text-align: left; text-decoration: none; vertical-align: baseline;">**<span style="background-color: transparent; color: #000000; font-size: 16px; text-align: left; text-decoration: none; vertical-align: baseline;">__Emetics__ ** __-__ Emetics used in cases of poisoning because they induce forceful emptying of the stomach. Efficacy declines when treatment is initiated more than 1 hour after ingestion of a toxic substance. No longer supported for use for accidental poisonings at home. <span style="background-color: transparent; color: #000000; display: block; font-size: 16px; text-align: left; text-decoration: none; vertical-align: baseline;">**__Adsorbents-__** Instead it is preferred to use activated charcoal as an adsorbent because it has been shown to reduce the bioavailability of ingested substances effectively. <span style="background-color: transparent; color: #000000; display: block; font-size: 16px; text-align: left; text-decoration: none; vertical-align: baseline;">**__Antiemetics-__** Are Drugs used to treat Nausea & Vomiting. Drugs or drug classes useful as antiemetics include; some antipsychotics that are used successfully for the nausea of pregnancy, postoperative emesis, or vomiting induced by radiation or chemotherapy. H1 antihistamines are effective antiemetics and anticholinergics scopolamine is used in the prevention & treatment of motion sickness. <span style="background-color: transparent; color: #000000; display: block; font-family: Times New Roman; font-size: 16px; text-align: left; text-decoration: none; vertical-align: baseline;">**<span style="background-color: transparent; color: #000000; font-size: 16px; text-align: left; text-decoration: none; vertical-align: baseline;">Laxatives ** - Constipation is a common GI complaint & Laxatives are used to relieve acute & chronic constipation, treat hemorrhoids, & prepare the bowel for examination (colonoscopy). Most overused OTC drug. > that coats the intestinal contents & softens stool. <span style="background-color: transparent; color: #000000; display: block; font-family: Times New Roman; font-size: 16px; text-align: left; text-decoration: none; vertical-align: baseline;"> <span style="background-color: transparent; color: #000000; display: block; font-family: Times New Roman; font-size: 16px; text-align: left; text-decoration: none; vertical-align: baseline;"> <span style="background-color: transparent; color: #000000; font-family: Times New Roman; font-size: 16px; text-align: left; text-decoration: none; vertical-align: baseline;">** __Antidiarrheal__ ** ** Agents **
 * <span style="background-color: transparent; color: #000000; display: block; font-family: Times New Roman; font-size: 16px; text-align: left; text-decoration: none; vertical-align: baseline;">**<span style="background-color: transparent; color: #000000; font-size: 16px; text-align: left; text-decoration: none; vertical-align: baseline;">Proton Pump ****<span style="background-color: transparent; color: #000000; font-size: 16px; text-align: left; text-decoration: none; vertical-align: baseline;">Inhibitors ** - PPIs are drugs that irreversible inhibit H+/K+ activated ATPase (proton pump) in the gastric parietal cell, the final pathway for acid secretion. PPIs have become the drug of choice for treating acid-related gastrointestinal diseases. All PPIs increase gastric pH and may alter absorption of drugs that are weak bases or acids or are formulated as pH dependent, controlled release products.
 * <span style="background-color: transparent; color: #000000; display: block; font-family: Times New Roman; font-size: 16px; text-align: left; text-decoration: none; vertical-align: baseline;">**<span style="background-color: transparent; color: #000000; font-size: 16px; text-align: left; text-decoration: none; vertical-align: baseline;">H2 Receptor ****<span style="background-color: transparent; color: #000000; font-size: 16px; text-align: left; text-decoration: none; vertical-align: baseline;">Antihistamines ** -Histamine is one of the primary mediators of gastric acid secretion, along with acetylcholine and gastrin. H2 antagonists, along with their antisecretory actions, also accelerate ulcer healing by the induction of endogenous prostanoid synthesis.
 * <span style="background-color: transparent; color: #000000; display: block; font-family: Times New Roman; font-size: 16px; text-align: left; text-decoration: none; vertical-align: baseline;">**<span style="background-color: transparent; color: #000000; font-size: 16px; text-align: left; text-decoration: none; vertical-align: baseline;">Antibiotics - ** PUD is has been demonstrated to be directly linked to gram negative organism H. Pylori. These findings have led to the routine use antibiotic therapy for the eradiction of gastric and duodenal ulcer. The current therapy for H. pylori associated peptic ulcers involve a triple regimen of a PPI with dual antibiotics clarithromycin and amoxicillin.
 * <span style="background-color: transparent; color: #000000; display: block; font-family: Times New Roman; font-size: 16px; text-align: left; text-decoration: none; vertical-align: baseline;">**<span style="background-color: transparent; color: #000000; font-size: 16px; text-align: left; text-decoration: none; vertical-align: baseline;">Gastric Antacids ** - weak bases that buffer or neutralize gastric hydrochloride (HCl) acid. To form a salt and reduce gastric acididty. Excessive neutralization may lead to acid rebound. All antacids may affect the absorption of other medications by directly binding to the drug or increasing the intragastric pH, altering the drugs solubility. Antacids taken on a empty stomach have a duration of action of 30 min. whereas antacids taken on after a meal may neutralize acid for 3 hours.
 * <span style="background-color: transparent; color: #000000; display: block; font-family: Times New Roman; font-size: 16px; text-align: left; text-decoration: none; vertical-align: baseline;"> Sodium bicarbonate: available in the form of baking soda and combination products. It reacts almost instantaneously to neutralize HCl to produce CO2 and NaCl. Formation of CO2 results in belching and gastric distension. Contraindicated in patients on a low-salt diet.
 * <span style="background-color: transparent; color: #000000; display: block; font-family: Times New Roman; font-size: 16px; text-align: left; text-decoration: none; vertical-align: baseline;"> Mg++ salts: ex. milk of magnesia. It reacts slowly with HCl to form MgCl2 and water. No CO2 is generated. Has laxative effects.
 * <span style="background-color: transparent; color: #000000; display: block; font-family: Times New Roman; font-size: 16px; text-align: left; text-decoration: none; vertical-align: baseline;"> Albuminum salts: aluminum hydroxide reacts with HCl to form AlCl3 and water. No CO2 is formed. The formation of insoluble salts limits its absorption. Most common side effect is constipation.
 * <span style="background-color: transparent; color: #000000; display: block; font-family: Times New Roman; font-size: 16px; text-align: left; text-decoration: none; vertical-align: baseline;"> Calcium carbonate: produces a potent and prolonged neutralization of HCl forming CO2 and CaCl2. Ca++ containing antacids may cause or worsen hypercalcemia, which is characterized by neurologic symptoms and reduced renal function. May produce constipation.
 * <span style="background-color: transparent; color: #000000; display: block; font-family: Times New Roman; font-size: 16px; text-align: left; text-decoration: none; vertical-align: baseline;">**<span style="background-color: transparent; color: #000000; font-size: 16px; text-align: left; text-decoration: none; vertical-align: baseline;">Stimulants- ** Exact mechanism is not completely understood, but drugs thought to act as a local irritant on the intestinal mucosa that increases propulsive activity. Examples are Castor oil, rarely used today, most commonly used stimulants is senna & cascara segrada.
 * <span style="background-color: transparent; color: #000000; display: block; font-family: Times New Roman; font-size: 16px; text-align: left; text-decoration: none; vertical-align: baseline;">**<span style="background-color: transparent; color: #000000; font-size: 16px; text-align: left; text-decoration: none; vertical-align: baseline;">Stool softeners ****<span style="background-color: transparent; color: #000000; font-size: 16px; text-align: left; text-decoration: none; vertical-align: baseline;"> & Lubricants- ** Docusate act like detergents & used to soften the stool, to lessen the discomfort or strain of defecation. Recommended for elderly patients because it has few side effects. Mineral oil is a lubricant
 * <span style="background-color: transparent; color: #000000; display: block; font-family: Times New Roman; font-size: 16px; text-align: left; text-decoration: none; vertical-align: baseline;">**<span style="background-color: transparent; color: #000000; font-size: 16px; text-align: left; text-decoration: none; vertical-align: baseline;">Saline & ****<span style="background-color: transparent; color: #000000; font-size: 16px; text-align: left; text-decoration: none; vertical-align: baseline;">osmotic Cathartics- ** saline cathartics are salt solutions that osmotically increase the water content of feces & fluid volume in the intestinal lumen, which increases pressure & exerts mechanical force to stimulat peristalsis. Contraindicated in patients with low salt diets, in patients with edema & CHF.
 * <span style="background-color: transparent; color: #000000; display: block; font-family: Times New Roman; font-size: 16px; text-align: left; text-decoration: none; vertical-align: baseline;">**<span style="background-color: transparent; color: #000000; font-size: 16px; text-align: left; text-decoration: none; vertical-align: baseline;">Bulk-Forming ****<span style="background-color: transparent; color: #000000; font-size: 16px; text-align: left; text-decoration: none; vertical-align: baseline;">Agents- ** include synthetic fibers & natural plant products. They have the property of absorbing water & expanding, increasing the bulk of the intestinal contents, & softens stool. Agents not absorbed & don’t interfere with absorption of nutrients in GI tract

Diarrhea occurs when not enough water is removed from the stool during transit, making the stool lose and poorly formed. Antidiarrheal agents act in one of two ways: they either soak up excess water or decrease intestinal Antidiarrheal agents may be used to treat acute diarrhea or control chronic diarrhea associated with conditions such as irritable bowel syndrome (IBS), or inflammatory bowel disease. Such agents as kaolin, bismuth, subsalicylate, and opioid preparations (diphenoxylate, and loperamide) have been determined by FDA to be safe and effective in the treatment of acute nonspecific diarrhea.


 * Kaolin **

Kaolin is a hydrated aluminum silicate with crystalline structure that allows for a large surface area that absorbs many times its weight in water. In the colon it may act as an absorbent or protectant, but the absorption is not selective, and it should not be used in children under 12 years without physician approval. If taken together, kaolin may absorb other medications and reduce their systematic absorption.


 * Bismuth Subsalicylate **

Bismuth Subsalicylate is a commonly used OTC agent in the treatment of various gastrointestinal symptoms and diseases, including dyspepsia and acute diarrhea, and in prevention of traveller’s diarrhea. In the stomach, the bismuth subsalicylate reacts with the hydrochloric acid to form bismuth oxychloride and salicylic acid. Bismuth subsalicylate has an excellent safety record, and side effects are minor. Salicylate-induced adverse reactions may occur after its administrations. Bismuth subsalicylate products are not recommended for patients younger than 12 years because of a lack of studies to prove efficacy in young children.


 * Opioid Preparations **

Opioids are effective and prompt-acting antidiarrheal agent. They act by enhancing tone in the anal sphincter and in segments of the longitudinal muscle of the gastrointestinal tract, while inhibiting propulsive contraction of circular and longitudinal muscle. Opioids cause a marked slowing of fluid movement through jejunum, but produce a minimal effect on the movement of fluid through the ileum of colon. Opioids increase net intestinal absorption of water and electrolytes, reducing stool volume. Commonly used opioid diarrheals include diphenoxylate and loperamide.


 * Diphenoxylate **

The efficacy of diphenoxylate was found to be approximately equal to that of camphorated tincture of opium in patients with diarrhea. Various minor side effects have been reported, including abdominal cramps, nausea, weakness, drowsiness, xerostomia, gingival swelling, partial intestinal obstruction, nd urinary retention.


 * Loperamide **

Loperamide is the most selective antidiarrheal opioid currently available for clinical use because it has a distribution within the body different from other opioids – only small amount of loperamide reach the brain. Its antidiarrheal effect is thought to result from interactions with µ-opioid receptors. Loperamide is safe and effective antidiarrheal agents. Adverse effects of loperamide occurs infrequently but include abdominal pain and distention, constipation, nausea and vomiting, dry mouth, and drowsiness or dizziness.

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