20/09/2017
Drugs for decreasing acidity are used for peptic ulcer, gastroesophageal reflux disease (GERD), and many forms of gastritis. Some drugs are used in regimens for treating Helicobacter pylori infection. Drugs include
Proton pump inhibitors
H2 blockers
Antacids
Prostaglandins
Proton pump inhibitors
These drugs are potent inhibitors of H+,K+-ATPase. This enzyme, located in the apical secretory membrane of the parietal cell, plays a key role in the secretion of H+ (protons). These drugs can completely inhibit acid secretion and have a long duration of action. They promote ulcer healing and are also key components of H. pylori eradication regimens. Proton pump inhibitors have replaced H2 blockers in most clinical situations because of greater rapidity of action and efficacy.
Proton pump inhibitors include esomeprazole, lansoprazole, and pantoprazole, Omeprazole, esomeprazole, and lansoprazole use in uncomplicated duodenal ulcers, omeprazole 20 mg po once/day or lansoprazole 30 mg po once/day is given for 4 wk. Complicated duodenal ulcers (ie, multiple ulcers, bleeding ulcers, those > 1.5 cm, or those occurring in patients with serious underlying illness) respond better to higher doses (omeprazole 40 mg once/day, lansoprazole 60 mg once/day or 30 mg bid). Gastric ulcers require treatment for 6 to 8 wk. Gastritis and GERD require 8 to 12 wk of therapy; GERD additionally often requires long-term maintenance.
Proton Pump Inhibitors
Drug
Most Conditions*
Gastric Ulcers and Complicated Duodenal Ulcers
Esomeprazole
40 mg once/day
40 mg bid
Lansoprazole
30 mg once/day
(Pediatric doses:
< 10 kg 7.5 mg once/day
10–20 kg 15 mg once/day
≥ 20 kg 30 mg once/day)†
30 mg bid
Omeprazole
20 mg once/day
(Pediatric dose: 1 mg/kg/day in a single dose or divided bid)†
40 mg once/day
Pantoprazole
40 mg once/day
40 mg bid
Rabeprazole
20 mg once/day
20 mg bid
*Gastritis, gastroesophageal reflux disease, uncomplicated duodenal ulcers.
†Representative doses. Data are limited to the use of proton pump inhibitors in children.
Long-term proton pump inhibitor therapy produces elevated gastrin levels, which lead to enterochromaffin-like cell hyperplasia. However, there is no evidence of dysplasia or malignant transformation in patients receiving this treatment. Some may develop vitamin B12 malabsorption.
H 2 blockers
These drugs (cimetidine, ranitidine, famotidine, available IV and orally; and nizatidine available orally) are competitive inhibitors of histamine at the H2 receptor, thus suppressing gastrin-stimulated acid secretion and proportionately reducing gastric juice volume. Histamine-mediated pepsin secretion is also decreased. Nizatidine, famotidine, cimetidine, and ranitidine are available without a prescription in the US.
H2 blockers are well absorbed from the GI tract, with onset of action 30 to 60 min after ingestion and peak effects at 1 to 2 h. IV administration produces a more rapid onset of action. Duration of action is proportional to dose and ranges from 6 to 20 h. Doses should often be reduced in elderly patients.
For duodenal ulcers, once daily oral administration of cimetidine 800 mg, ranitidine 300 mg, famotidine 40 mg, or nizatidine 300 mg given at bedtime or after dinner for 6 to 8 wk is effective. Gastric ulcers may respond to the same regimen continued for 8 to 12 wk, but because nocturnal acid secretion is less important, morning administration may be equally or more effective. Children ≥ 40 kg may receive adult doses. Below that weight, the oral dosage is ranitidine 2 mg/kg q 12 h and cimetidine 10 mg/kg q 12 h. For GERD, H2 blockers are now mostly used for pain management. Gastritis heals with famotidine or ranitidine given bid for 8 to 12 wk...
