Pantoprazole
Pantoprazole, sold under the brand name Protonix, among others, is a proton pump inhibitor used for the treatment of stomach ulcers, short-term treatment of erosive esophagitis due to gastroesophageal reflux disease (GERD), maintenance of healing of erosive esophagitis, and pathological hypersecretory conditions including Zollinger–Ellison syndrome. It may also be used along with other medications to eliminate Helicobacter pylori. Effectiveness is similar to other proton pump inhibitors (PPIs). It is available by mouth and by injection into a vein.Common side effects include headaches, diarrhea, vomiting, abdominal pain, and joint pain. More serious side effects may include severe allergic reactions, a type of chronic inflammation known as atrophic gastritis, Clostridium difficile colitis, low magnesium, and vitamin B12 deficiency. Use in pregnancy appears to be safe. Pantoprazole is a proton pump inhibitor that decreases gastric acid secretion. It works by inactivating (H+/K+)-ATPase function in the stomach.Study of pantoprazole began in 1985, and it came into medical use in Germany in 1994. It is available as a generic medication. In 2020, it was the twentieth most commonly prescribed medication in the United States, with more than 26 million prescriptions.

Medical uses
Pantoprazole is used for short-term treatment of erosion and ulceration of the esophagus for adults and children five years of age and older caused by gastroesophageal reflux disease. It can be used as a maintenance therapy for long-term use after initial response is obtained, but there have not been any controlled studies about the use of pantoprazole past a duration of 12 months. Pantoprazole may also be used in combination with antibiotics to treat ulcers caused by Helicobacter pylori. It can also be used for long-term treatment of Zollinger-Ellison syndrome. It may be used to prevent gastric ulcers in those taking NSAIDs.For improved efficacy of pantoprazole, the oral tablet formulation is taken half an hour prior to ingestion of food. In the hospital, intravenous administration is indicated when patients are unable to take the medication by mouth.

Children
Pantoprazole is only indicated for the short-term treatment of erosive esophagitis in children ages seven and older; and the safety and effectiveness of pantoprazole have only been established in the treatment of erosive esophagitis in children.

Elderly
The incidence of adverse effects occurring in people aged 65 years and older was similar to that in people aged 65 years and less.

Pregnancy
In reproductive studies using doses largely greater than the recommended doses performed on rats and rabbits, there was no evident harm on the development of the baby.

Breast feeding
Pantoprazole has been found to pass through the breast milk. However, in rodent cancer studies, pantoprazole has been shown to potentially cause tumor growth. The clinical relevance of the finding is unknown, but risks and benefits are recommended for consideration in determining the use of therapy for the mother and child.

Adverse effects
Infection: Stomach acid plays a role in killing ingested bacteria. Use of pantoprazole may increase the chance of developing infections such as pneumonia, particularly in hospitalized patients.

Common
Gastrointestinal: abdominal pain (6%), diarrhea (9%), flatulence (4%), nausea (7%), vomiting (4%)
Neurologic: headache (12%), dizziness (3%)
Neuromuscular and skeletal: arthralgia (3%)

Rare
Gastrointestinal: constipation, dry mouth, hepatitis
Blood problems: low white blood cell count, thrombocytopenia
Immunologic: Stevens–Johnson syndrome, toxic epidermal necrolysis
Metabolic: elevated creatine kinase, elevated cholesterol levels, elevated liver enzymes (AST/ALT), swelling
Musculoskeletal: Muscle disorders, bone fracture and infection, Clostridium difficile infection, osteoporosis-related hip fracture, rhabdomyolysis
Kidneys: interstitial nephritis
Nutrition:  may reduce the absorption of important nutrients, vitamins, and minerals, including certain medications, leaving users at increased risk for pneumonia.

Long-term use
Osteoporosis and bone fracture have been observed in people on high-dose and/or long-term (over one year) prescription proton pump inhibitors.
Hypomagnesia has been observed in people on medications like pantoprazole when taken for longer periods of time (generally one year or more, although cases have been reported with regimens as short as three months).
Deficiencies such as vitamin B12 deficiency, iron deficiency, and calcium deficiency may be seen with long term use. Vitamin B12 deficiency is due to the change in the acidic environment within the stomach with the use of pantoprazole which prevents peptidases from being activated. This prevents the cleaving of R-factor from vitamin B12 and prevents its absorption.
Rebound hypergastrinemia may be seen when stopping the medication after long term use.

Discontinuation
In people taking PPIs for longer than six months, a dose taper should be considered prior to discontinuation. For those on a moderate to high dose, this can be done by 50 percent every week until on the lowest dose. After a week it can then be stopped.

Interactions
Due to its effect of reducing stomach acidity, use of pantoprazole can affect absorption of drugs that are pH-sensitive, such as ampicillin esters, ketoconazole, atazanavir, iron salts, amphetamine and mycophenolate mofetil.Additional medications that are affected include bisphosphonate derivatives, fluconazole, clopidogrel, and methotrexate.

Pharmacology
The mechanism of action of pantoprazole is to inhibit the final step in gastric acid production. In the gastric parietal cell of the stomach, pantoprazole covalently binds to the H+/K+ ATP pump to inhibit gastric acid and basal acid secretion. The covalent binding prevents acid secretion for up to 24 hours and longer.Pantoprazole is metabolized in the liver by the cytochrome P450 system. Metabolism mainly consists of demethylation by CYP2C19 followed by sulfation. Another metabolic pathway is oxidation by CYP3A4. Pantoprazole metabolites are not thought to have any pharmacological significance. It is usually given with a prokinetic drug because of inactivity in the acidic environment of the stomach. Pantoprazole binds irreversibly to H+K+ATPase (proton pumps) to suppress the secretion of acid. Due to irreversible binding of the pumps, new pumps have to be made before acid production can be resumed. The drugs plasma half-life is about two hours. After administration, the time for the drug to reach peak plasma concentrations is 2 to 3 hours. The percentage of the drug that is protein bound is 98%.In veterinary medicine, pantoprazole appears to be safe to use in several large animal species. The pharmacokinetics of pantoprazole have been explored in several veterinary species, including calves, alpacas and foals with half lives reported as 2.81, 0.47, and 1.43 hours, respectively. Pantoprazole appears to be eliminated more quickly in goats when compared to calves, with goats having an elimination half-life of less than one hour.

History
Pantoprazole was discovered by scientists at Byk Gulden, a subsidiary of Altana; the drug discovery program started in 1980, producing pantoprazole in 1985. The compound was actually created by chemists working on scale-up of a different chemical that had been chosen as a development candidate.: 117, 129   Byk Gulden partnered with Smith Kline & French in 1984.: 124   The compounds development names were BY1029 and SK&F96022.: 123  By 1986 the companies had created the sodium salt, pantoprazole sodium sesquihydrate, and decided to develop it as it was more soluble and stable, and was more compatible with other ingredients used in the formulation.: 130   It was first marketed in Germany in 1994.: 130   Wyeth licensed the US patent from Altana, and obtained marketing approval from the US FDA in 2000 under the trade name Protonix.In 2004, worldwide sales of the drug were $3.65 billion, about half of which were in the US.In 2007, Altanas drug business was acquired by Nycomed. Nycomed was in turn acquired by Takeda in 2011 and Wyeth was acquired by Pfizer in 2009.The patent protecting the drug was set to expire in 2010, but Teva Pharmaceuticals filed an Abbreviated New Drug Application (ANDA) in 2007, and Wyeth and Nycomed sued Teva for patent infringement, but Teva decided to launch its generic drug "at risk" that year, before the patent had been invalidated.  Wyeth launched an authorized generic in 2008.  Pfizer and Takedas patent exclusivity expired in 2010, and an administrative exclusivity they had for pediatric use expired in January 2011, and full generic competition began. The litigation between Teva and Pfizer/Takeda was settled in 2013, with Teva paying the patent holders $2.15 billion in damages for its early launch.

Society and culture
As of 2017, the drug was marketed under many brands worldwide, including as a combination drug with domperidone, a combination with itopride, in combination with both clarithromycin and amoxicillin, in combination with  levosulpiride, and in combination with naproxen.

Other animals
Pantoprazole has been demonstrated to increase the 3rd compartment pH in alpacas. It has been shown to be generally safe to use in cattle, sheep and goats.

See also
Hyoscine butylbromide
Pirenzepine

References
External links
"Pantoprazole". Drug Information Portal. U.S. National Library of Medicine.