*Review of Gastroesophageal Reflux Pharmacotherapy Management DOI: http://dx.doi.org/10.5772/intechopen.106338*

work by inhibiting the proteolytic activity of pepsin and additionally increase the tone of the lower esophageal sphincter (LES) when pH is >4 [9]. Calcium carbonate absorbs primarily in the duodenum and changes with age (60% for infants, 28% for prepubertal children, 34% for pubertal children, and 25% for adults). It is important to note that absorption doubles during pregnancy [9]. Solubility of calcium carbonate increases with increasing acidity [9]. Constipation, diarrhea, nausea, vomiting, and hypophosphatemia are common side effects of antacid use [9]. Drug interactions with antacids are common and may involve interactions with medications such as levothyroxine, fluoroquinolones, tetracyclines, iron supplements, and salicylates. These interactions typically result in decreased absorption of the aforementioned medications and can affect therapy [9]. In order to minimize the effects of antacids on the absorption of other medications, the recommendation is to administer the medications 2 hours before or up to 6 hours after taking antacids [9]. Historically, antacids were the first-line medication for the treatment of peptic ulcer disease (PUD) prior to the introduction of PPIs [9]. Due to their familiarity and low cost, antacids are still very commonly used to treat heartburn. When used for the treatment of heartburn, patients are recommended to consult their physician if symptoms persist after 14 days of use. Antacids represent a low-cost, relatively safe option for patients with intermittent GERD symptoms but have the potential to mask more serious problems, which is why long-term unsupervised use is not recommended [9].

The use of antacids in renal dysfunction can lead to the accumulation of aluminum and magnesium. Accumulation begins when creatinine clearance (CrCl) is less than 25 ml/min, and use is not recommended when CrCl < 10 ml/min. No current dose adjustments are recommended to prevent accumulation for those with renal dysfunction [10]. For patients on hemodialysis, antacids should not be used unless patients can be reliably monitored, including signs and symptoms of toxicity and serum magnesium levels. Symptoms of hypermagnesemia include anorexia and nausea due to magnesium's depressant effect on the central nervous system.

Additionally, hypermagnesemia can cause to skeletal muscle weakness and decreased deep tendon reflexes [11, 12]. Other signs of magnesium toxicity include electrocardiographic changes, muscle weakness, and hypotension [11, 12]. Aluminum accumulation can lead to 'dialysis dementia' (impaired cognition), dialysis osteomalacia, and dialysis encephalopathy [11, 12].
