Pantoprazole

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Pantoprazole (pantoprazole sodium) is sold under several brand names, including Protonix, Pantopan, Astropan, Controloc, Pantecta, Pantozol, Protium, Pantor, and Pantoloc. Each brand has different manufacturers. Two pharmaceutical companies, Wyeth-Ayerst Laboratories and Pfizer market Pronix and Somac, respectively. The U.S. Food and Drug Administration approved pantoprazole on February 2, 2000. Pantoprazole is used to treat Gastroesophageal Reflux Disease (GERD) in which excess stomach acid backs up into the esophagus. It is also used to reduce excessive gastric acid secretion. Pantoprazole sodium is a proton pump inhibitor (PPI), and the mechanism by which it works is to prevent the secretion of hydrogen ions (of the hydrochloric acid) into the stomach.


Contents

Uses/Indications

Pantoprazole is approved to treat the reflux or heartburn symptoms of Gastroesophageal Reflux Disease. GERD is caused by the backward flow of acid from the stomach into the esophagus (the tube which connects the nouth to the stomach).This reflux of acid causes deterioration of the lining of the esophagus, which leads to the formation of ulcers (sores). Pantoprazole is also used to treat diseases characterized by excessive secretion of stomach acid, including Zollinger-Ellison syndrome (ZES) and other neoplastic (cancerous cell growth) disorders. Most ZE tumors are located in the duodenum or pancreas.

How Pantoprazole is Taken

Pantoprazole is given in either tablets of 20 mg or 40 mg, or as an intravenous (IV) infusion of 40 mg. Pantoprazole is provided in a delayed-release, or extended-release form, which allows once daily administration. Typical dosage regimens consist of 40 mg daily for eight weeks. If needed, daily dosing is extended for another eight weeks. The intravenous infusion is given once or twice daily. Higher doses, typically 160 to 240 mg, are used in conditions characterized by a high rate of acid production, such as in Zollinger-Ellison syndrome.

Pantoprazole is most effective when taken in the morning on an empty stomach, such as 30 minutes before breakfast.

How Pantoprazole Works

The cells lining the stomach secrete hydrogen ions (hydrochloric acid, HCl) into the stomach. The hydrogen ion (proton) is the component of gastric secretions which makes it acidic. Hydrogen ions are pumped into the interior by proteins called proton pumps. Pantoprazole inhibits this proton pump reducing hydrogen ion accumulation in the stomach. Gastric acid secretion is inhibited both during rest and when the stomach is stimulated by food.

How the Body Affects Pantoprazole

Certain drugs including pantoprazole sodium are metabolized, or modified, by liver enzymes called CYP2C19 and CYP3A4. These drugs are metabolized to make them more water-soluble and easier to excrete. Pantoprazole is metabolized quickly, and the amount of time needed for the concentration of pantoprazole in the body to be reduced by half, called the the half-life of a drug, is one hour. The advent of an extended-release form has helped overcome this short half-life to allow only daily dosing. Pantoprazole is largely excreted in the urine. Because pantoprazole is metabolized in the liver, severe liver damage may cause the drug to accumulate in the body. Whether this accumulation has any adverse, or beneficial, effect is not known.

Influence of Genes

The activity of CYP2C19 is reduced in some people because of mutations in the gene encoding this enzyme. The liver's ability to metabolize or clear out these drugs from the body's system is prolonged. Slow metabolizers is a term used for patients who experience this. The half-life of pantoprazole is then increased to 3 hours or more because of their inability to metabolize the drug. [1][2]

This in turn increases blood levels of pantoprazole. However, these changes are not expected to have any significant effect on the effectiveness or safety of the drug.

Risks and Precautions

  • The use of pantoprazole may cause a false positive result on a test for tetrahydrocannabinal (THC, the active component of marijuana).
  • The tablet is taken whole, i.e., it is not crushed.
  • The effectiveness and safety of pantoprazole is not known in individuals with severe liver damage.

Side Effects

Below are some of the more common side effects of pantoprazole:

The side effects are generally mild and of short duration.

Drug Interactions

Pantoprazole may reduce blood levels of drugs that are dependent on stomach acidity for optimal absorption. Accordingly, pantoprazole may reduce absorption of drugs such as ketoconazole (Nizoral), ampicillin, and iron salts.

Overdose

A few overdoses with pantoprazole have been reported.[3] However, no adverse effects have been reported after single doses of up to 600mg. In addition, treatment for three months with 320 mg pantoprazole or for seven days with 240 mg intravenous pantoprazole was well-tolerated.

Effectiveness

The success rate of treatment with pantoprazole in patients with GERD is very high. A study of 603 patients with GERD found that healing rates for patients given placebo, 20 mg pantoprazole, or 40 mg pantoprazole daily were 14%, 55%, and 72%, respectively. [4] Healing was faster in patients given 40 mg pantoprazole compared to either 20 mg pantoprazole or placebo. The effectiveness of on-demand, long-term pantoprazole was studied in 634 patients with mild GERD. [5] Over the six-month study period, patients given either 20 mg or 40 mg pantoprazole reported fewer symptoms of GERD and less antacid use than did patients given a placebo. The number of symptoms and antacid use did not differ between patients given either the 20 mg or 40 mg dose. A comparison among treatments with 40 mg pantoprazole orally or intravenously, or placebo was performed in 78 patients with GERD.[6]Oral and intravenous pantoprazole was equally effective in reducing gastric acid secretion, and both were superior to placebo.

Alternatives

Other proton pump inhibitors include omeprazole (Prilosec, esomeprazole (Nexium) , lansoprazole (Prevacid) , and rabeprazole (Aciphex) . They differ in effectiveness, safety, and potential for drug interactions.


The video below describes several different approaches to treating GERD:


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References

  1. Tanaka M, Ohkubo T, Otani K, et al. Stereoselective pharmacokinetics of pantoprazole, a proton pump inhibitor, in extensive and poor metabolizers of S-mephenytoin. Clin Pharmacol Ther. 2001 Mar;69(3):108-13. Abstract
  2. Tanaka M, Ohkubo T, Otani K, et al. Metabolic disposition of pantoprazole, a proton pump inhibitor, in relation to S-mephenytoin 4'-hydroxylation phenotype and genotype. Clin Pharmacol Ther. 1997 Dec;62(6):619-28. Abstract
  3. Food and Drug Administration. Protonix (Pantoprazole sodium) Drug Label. PDF.
  4. Richter JE, Bochenek W. Oral pantoprazole for erosive esophagitis: a placebo-controlled, randomized clinical trial. Pantoprazole US GERD Study Group. Am J Gastroenterol. 2000 Nov;95(11):3071-80. Abstract
  5. Scholten T, Dekkers CP, Schütze K, Körner T, Bohuschke M, Gatz G. On-demand therapy with pantoprazole 20 mg as effective long-term management of reflux disease in patients with mild GERD: the ORION trial. Digestion. 2005;72(2-3):76-85. Abstract
  6. Pratha V, Hogan DL, Lynn RB, Field B, Metz DC. Intravenous pantoprazole as initial treatment in patients with gastroesophageal reflux disease and a history of erosive esophagitis: a randomized clinical trial. Dig Dis Sci. 2006 Sep;51(9):1595-601. Abstract

External Links

How Protonix Works Video from Wyeth

Product Information from Wyeth Pharmaceuticals

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