Antacids are a group of drugs that have been on the market for several 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 for the relief of mild intermittent gastroesophageal reflux disease (GERD) associated heartburn . The estimated prevalence of heartburn at least once per week in North America ranges from 18% to 28% with 25% adults reporting heartburn on a daily basis. ,,
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 the 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 have a characteristic pharmacological property that determines its clinical use. Antacids have been used for the following:
The antacids reduce the acid reaching the duodenum by neutralizing the acid present in the stomach. The main objectives are:
The salts' mechanism of neutralization of acid varies, and each salt has a different mechanism with the ultimate goal of acid neutralization.
The formulation of aluminum hydrochloride and water results in neutralization of the acid in the stomach. It is also known to inhibit pepsin activity. 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., Nevertheless, it is known to heal chronic ulcers and prevent acute mucosal damage induced chemically by reducing access to pepsin and acid. Sucralfate likes its aluminum hydroxide component is known to stimulate angiogenesis and granulation tissue formation.
Aluminum hydroxide is also useful in hyperphosphatemia due to its ability to bind phosphate in the gastrointestinal (GI) tract and subsequently prevent absorption of phosphate .
They neutralize gastric acidity resulting in increased gastric and duodenal bulb pH; they additionally inhibit the proteolytic activity of pepsin 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 provide relief from symptoms of heartburn. The calcium salts also form combined insoluble compounds with dietary phosphate and prevent the absorption of later.
The acid neutralizing mechanism of the antacids is well understood as mentioned above. In addition to this, there are other mechanisms that 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
The dose for antacids depends upon the age of the patient, the purpose of administration (neutralization of acid or off-label use) and presence of other comorbidities like renal or hepatic impairment. As all the forms of these medications are available as over the counter medication, the dosing recommendation varies by product/and or manufacturer.
Aluminum Hydroxide (Antacid)
Calcium Carbonate (Antacid)
It is used up to a maximum dose of 8000 mg per day up to 2 weeks with 1 to 4 tablets for symptomatic relief.
The total dose is not to exceed 2000 mg per day.
Pregnancy and Breastfeeding
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., In 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. The maternal calcium intake also affects the amount of calcium excreted in the breast milk; it is believed that the use of calcium-containing antacids is safe during breastfeeding. 
The adverse effects are prominent in the infants and the elderly population. The chronic use of antacids in this population is not recommended due to safety concerns.
Aluminum use is associated with an increased risk of toxicity in individuals with renal failure and infants. It presents as:
The adverse reactions often seen with this group of antacids are:
The absolute contraindication is hypersensitivity to any component of the formulation. Also, the drug is to be used with caution in patients with:
The average therapeutic dose of antacid is 10 to 15 mL (1 tablespoon or 1 package content) of liquid or 1 to 2 tablets 3 to 4 times a day. Periodic monitoring of calcium and phosphorus levels is suggested in patients on chronic therapy.
No information is available regarding toxicities caused by aluminum- and calcium-containing antacids. However, antacids are to be used cautiously in the high-risk population mentioned above.
Antacids are available as over the counter medications, meaning that patients do not require a prescription to obtain them. This results in the improper use of these medications with little to no relief of symptoms. There is a need to educate patients regarding the importance of a correct mode of administration, time of administration, and dosage for the prompt and prolonged relief of symptoms. These medications only provide symptomatic relief, which may mask an underlying disorder, but lack of awareness in this regard delays diagnosis in health conditions like GERD, peptic ulcer, gastric ulcer, and hiatal hernia. Although these medications do not cause toxicities in high doses, it is imperative to understand their interaction with other medications especially in patients on polypharmacy. The physicians, nurses, pharmacists, and the pharmaceutical companies have a combined responsibility to educate the patients regarding the safe use of these medications to improve outcomes.
|||Sontag SJ, The medical management of reflux esophagitis. Role of antacids and acid inhibition. Gastroenterology clinics of North America. 1990 Sep [PubMed PMID: 1977703]|
|||El-Serag HB,Sweet S,Winchester CC,Dent J, Update on the epidemiology of gastro-oesophageal reflux disease: a systematic review. Gut. 2014 Jun [PubMed PMID: 23853213]|
|||Moayyedi P,Axon AT, Review article: gastro-oesophageal reflux disease--the extent of the problem. Alimentary pharmacology [PubMed PMID: 16042655]|
|||Shaker R,Castell DO,Schoenfeld PS,Spechler SJ, Nighttime heartburn is an under-appreciated clinical problem that impacts sleep and daytime function: the results of a Gallup survey conducted on behalf of the American Gastroenterological Association. The American journal of gastroenterology. 2003 Jul [PubMed PMID: 12873567]|
|||Eisen G, The epidemiology of gastroesophageal reflux disease: what we know and what we need to know. The American journal of gastroenterology. 2001 Aug [PubMed PMID: 11510763]|
|||Maton PN,Burton ME, Antacids revisited: a review of their clinical pharmacology and recommended therapeutic use. Drugs. 1999 Jun [PubMed PMID: 10400401]|
|||Weberg R,Berstad K,Berstad A, Acute effects of antacids on gastric juice components in duodenal ulcer patients. European journal of clinical investigation. 1990 Oct [PubMed PMID: 2124982]|
|||Tarnawski A,Tanoue K,Santos AM,Sarfeh IJ, Cellular and molecular mechanisms of gastric ulcer healing. Is the quality of mucosal scar affected by treatment? Scandinavian journal of gastroenterology. Supplement. 1995 [PubMed PMID: 8578218]|
|||Soll AH,Weinstein WM,Kurata J,McCarthy D, Nonsteroidal anti-inflammatory drugs and peptic ulcer disease. Annals of internal medicine. 1991 Feb 15 [PubMed PMID: 1987878]|
|||Schucker JJ,Ward KE, Hyperphosphatemia and phosphate binders. American journal of health-system pharmacy : AJHP : official journal of the American Society of Health-System Pharmacists. 2005 Nov 15 [PubMed PMID: 16278327]|
|||Rodriguez-Stanley S,Ahmed T,Zubaidi S,Riley S,Akbarali HI,Mellow MH,Miner PB, Calcium carbonate antacids alter esophageal motility in heartburn sufferers. Digestive diseases and sciences. 2004 Nov-Dec [PubMed PMID: 15628717]|
|||Tarnawski A,Hollander D,Gergely H, Antacids: new perspectives in cytoprotection. Scandinavian journal of gastroenterology. Supplement. 1990 [PubMed PMID: 2205902]|
|||K/DOQI clinical practice guidelines for bone metabolism and disease in chronic kidney disease. American journal of kidney diseases : the official journal of the National Kidney Foundation. 2003 Oct [PubMed PMID: 14520607]|
|||Chao HH,Guo CH,Huang CB,Chen PC,Li HC,Hsiung DY,Chou YK, Arsenic, cadmium, lead, and aluminium concentrations in human milk at early stages of lactation. Pediatrics and neonatology. 2014 Apr [PubMed PMID: 24231114]|
|||Fanni D,Ambu R,Gerosa C,Nemolato S,Iacovidou N,Van Eyken P,Fanos V,Zaffanello M,Faa G, Aluminum exposure and toxicity in neonates: a practical guide to halt aluminum overload in the prenatal and perinatal periods. World journal of pediatrics : WJP. 2014 May [PubMed PMID: 24801228]|
|||Mahadevan U,Kane S, American gastroenterological association institute medical position statement on the use of gastrointestinal medications in pregnancy. Gastroenterology. 2006 Jul [PubMed PMID: 16831610]|
|||Tsou VM,Young RM,Hart MH,Vanderhoof JA, Elevated plasma aluminum levels in normal infants receiving antacids containing aluminum. Pediatrics. 1991 Feb [PubMed PMID: 1987526]|
|||Woodard-Knight L,Fudge A,Teubner J,Simmer K, Aluminium absorption and antacid therapy in infancy. Journal of paediatrics and child health. 1992 Jun [PubMed PMID: 1605980]|
|||Sedman A, Aluminum toxicity in childhood. Pediatric nephrology (Berlin, Germany). 1992 Jul [PubMed PMID: 1498007]|
|||Robinson RF,Casavant MJ,Nahata MC,Mahan JD, Metabolic bone disease after chronic antacid administration in an infant. The Annals of pharmacotherapy. 2004 Feb [PubMed PMID: 14742764]|
|||Pivnick EK,Kerr NC,Kaufman RA,Jones DP,Chesney RW, Rickets secondary to phosphate depletion. A sequela of antacid use in infancy. Clinical pediatrics. 1995 Feb [PubMed PMID: 7729110]|