Gastric Antacid
The gastric and upper-airway flora of 60 consecutive patients treated with antacids or cimetidine in a respiratory/surgical intensive-therapy unit were studied. In 52 (87.0%) patients one or more organisms were cultured simultaneously from both upper airway and stomach. A sequence of transmission was clear in 17 of these patients. Pneumonia due to gram-negative bacilli developed in 31 patients; in most cases the causative organisms were of gastric origin. No pneumonia developed in the 8 patients whose gastric and upper-airway flora were different. The number of gram-negative bacilli in gastric aspirates correlated with the pH of the gastric aspirate. Treatment of seriously ill patients with antacids or cimetidine may encourage airway colonisation and predispose the patients to pneumonia caused by gram-negative bacilli.
gastric antacid
An antacid is a substance which neutralizes stomach acidity and is used to relieve heartburn, indigestion or an upset stomach.[1] Some antacids have been used in the treatment of constipation and diarrhea.[2] Marketed antacids contain salts of aluminium, calcium, magnesium, or sodium.[2] Some preparations contain a combination of two salts, such as magnesium carbonate and aluminium hydroxide (e.g. hydrotalcite).[3]
Antacids are available over the counter and are taken by mouth to quickly relieve occasional heartburn, the major symptom of gastroesophageal reflux disease and indigestion. Treatment with antacids alone is symptomatic and only justified for minor symptoms.[4] Alternative uses for antacids include constipation, diarrhea, hyperphosphatemia, and urinary alkalization.[5] Some antacids are also used as an adjunct to pancreatic enzyme replacement therapy in the treatment of pancreatic insufficiency.[6]
Non-particulate antacids (sodium citrate) increase gastric pH with little or no effect on gastric volume, and therefore may see some limited use in pre-operative procedures. Sodium citrate should be given within 1 hour of surgery to be the most effective.[7]
Conventional effervescent tablets contain a significant amount of sodium and are associated with increased odds of adverse cardiovascular events according to an 2013 study.[8] Alternative sodium-free formulations containing magnesium salts may cause diarrhea, whereas those containing calcium or aluminum may cause constipation. Rarely, long-term use of calcium carbonate may cause kidney stones. Long-term use of antacids containing aluminum may increase the risk of developing osteoporosis.[9] In vitro studies have found a potential for acid rebound to occur due to antacid overuse, however the significance of this finding has been called into question.[10][11]
When an excess amount of acid is produced in the stomach, the natural mucous barrier that protects the lining of the stomach can degrade, leading to pain and irritation. There is also potential for the development of acid reflux, which can cause pain and damage to the esophagus. Antacids contain alkaline ions that chemically neutralize stomach gastric acid, reducing damage to the stomach lining and esophagus, and relieving pain.[1] Some antacids also inhibit pepsin, an enzyme that can damage the esophagus in acid reflux.[5][12]
Antacids are known to interact with several oral medications, including fluoroquinolone and tetracycline antibiotics, iron, itraconazole, and prednisone.[13] Metal chelation is responsible for some of these interactions (e.g. fluoroquinolones, tetracyclines), leading to decreased absorption of the chelated drug. Some interactions may be due to the pH increase observed in the stomach following antacid ingestion, leading to increased absorption of weak acids, and decreased absorption of weak bases. Antacids also cause an increase in pH of the urine (alkalization), which may cause increased blood concentrations of weak bases, and increased excretion of weak acids.[14]
A proposed method to mitigate the effects of stomach acidity and chelation on drug absorption is to space out the administration of antacids with interacting medications, however this method has not been well studied for drugs affected by urine alkalization.[13]
There are concerns regarding interactions between delayed-release tablets and antacids, as antacids may increase the stomach pH to a point at which the coating of the delayed-release tablet will dissolve, leading to degradation of the drug if it is pH sensitive.[14]
Several liquid antacid preparations are marketed. Common liquid preparations include milk of magnesia and magnesium/aluminum combinations. A potential advantage of using a liquid preparation over a tablet is that liquids may provide quicker relief, however this may coincide with a shorter duration of action.[16]
Chewable tablets are one of the most common forms of antacids, and are readily available over the counter. Upon reaching the stomach, the tablet powder will dissolve in the stomach acid, allowing the cations to be released and neutralize excess stomach acid. Common salts available in tablet form include those of calcium, magnesium, aluminum, and sodium.[13]
Effervescent tablets are tablets which are designed to dissolve in water, and then release carbon dioxide.[18][19][20] Common ingredients include citric acid and sodium bicarbonate, which react when in contact with water to produce carbon dioxide. Effervescent antacids may also contain aspirin,[21] sodium carbonate, or tartaric acid.[22] Those containing aspirin may cause further gastric irritation and ulceration due to aspirin's effects on the mucous membrane of the stomach.[23]
Antacids are a group of drugs that have been on the market for many years. They were initially first-line defense against peptic ulcer disease; however, the discovery of proton pump inhibitors revolutionized the treatment of peptic ulcer disease. Currently, antacid use is restricted to relieve mild intermittent gastroesophageal reflux disease (GERD) with associated heartburn. This activity reviews the indications, contraindications, pharmaceutical action, adverse events, and other key elements of antacid therapy in the clinical setting as relates to the essential points needed by members of an interprofessional team managing the care of patients with heartburn and mild GERD.
Objectives:Identify the mechanism of action antacids.Summarize the indications for antacid therapy, including relevant interactions with other medications. Review the potential adverse events associated with the use of antacids.Outline the role of interprofessional coordination in guiding patient care and improving outcomes when using antacid therapy.Access free multiple choice questions on this topic.
Antacids are a group of drugs that have been on the market for many years. They were initially first-line defense against peptic ulcer disease; however, the discovery of proton pump inhibitors revolutionized the treatment of peptic ulcer disease. Currently, antacid use is restricted to relieving mild intermittent gastroesophageal reflux disease (GERD) associated with heartburn.[1] The estimated prevalence of heartburn at least once per week in North America ranges from 18% to 28%, with 25% of adults reporting heartburn daily.[2][3][4][5]
Antacids are medications that do not require a prescription; in other words, they are self-prescribed. Antacids are a combination of various compounds with various salts of calcium, magnesium, and aluminum as active ingredients. The antacids act by neutralizing the acid in the stomach and by inhibiting pepsin, which is a proteolytic enzyme. Each of these cationic salts has a characteristic pharmacological property that determines its clinical use. Antacids have therapeutic use for the following[6]:
The formulation of aluminum hydrochloride and water results in the neutralization of the acid in the stomach. It is also known to inhibit pepsin activity.[7] Aluminum hydroxide is complexed with a sulfated polysaccharide sucrose octasulfate to form sucralfate. This complex does not have a significant buffering action against the acid or has no effect on the pepsin secretion, and does not alter the gastric acid production in any way.[8][9] Nevertheless, it is known to heal chronic ulcers and prevent acute mucosal damage induced chemically by reducing access to pepsin and acid. Sucralfate, like its aluminum hydroxide component, is known to stimulate angiogenesis and granulation tissue formation.[8]
Calcium salts neutralize gastric acidity, resulting in increased gastric and duodenal bulb pH; they also inhibit pepsin's proteolytic activity if the pH is greater than 4 and increase lower esophageal sphincter tone. The calcium released from calcium carbonate is known to increase peristalsis in the esophagus, pushing the acid into the stomach and providing relief from heartburn symptoms. The calcium salts also form combined insoluble compounds with dietary phosphate and prevent the absorption of the latter.[11]
The acid-neutralizing mechanism of the antacids is well understood, as mentioned above. In addition to this, other mechanisms add to the ulcer healing properties of this class of drugs. The exact mechanism is still unclear, but it is believed to be a combination of[12][7]:
The dose for antacids depends upon the patient's age, the purpose of administration (neutralization of acid or off-label use), and the presence of other comorbidities like renal or hepatic impairment. As all the forms of these medications are available in over-the-counter formulations, the dosing recommendation varies by product/and or manufacturer.
Antacids containing aluminum salts are safe to be used in pregnant women as well as for women during labor for aspiration prophylaxis. The information regarding the use of aluminum-containing antacids in breastfeeding females has not been studied, but aluminum is known to be endogenous to breast milk.[14][15] In the case of calcium-containing antacids, excessive use is to be avoided in pregnant women as calcium crosses the placenta. The amount of calcium reaching the fetus is dependent on the physiological changes in the mother. Maternal calcium intake also affects the amount of calcium excreted in breast milk; the currently prevailing opinion is that the use of calcium-containing antacids is safe during breastfeeding.[16] 041b061a72