indication

Short-term (up to 16 weeks) treatment of erosive esophagitis.

pharmacology

Pantoprazole is a substituted benzimidazole indicated for the short-term treatment (up to 16 weeks) in the healing and symptomatic relief of erosive esophagitis. Pantoprazole is a proton pump inhibitor (PPI) that suppresses the final step in gastric acid production.

mechanism of action

Pantoprazole is a proton pump inhibitor (PPI) that suppresses the final step in gastric acid production by forming a covalent bond to two sites of the (H⁺,K⁺ )- ATPase enzyme system at the secretory surface of the gastric parietal cell. This effect is dose- related and leads to inhibition of both basal and stimulated gastric acid secretion irrespective of the stimulus.

toxicity

Single intravenous doses of pantoprazole at 378, 230, and 266 mg/kg (38, 46, and 177 times the recommended human dose based on body surface area) were lethal to mice, rats and dogs, respectively. The symptoms of toxicity included hypoactivity, ataxia, hunched sitting, limb-splay, lateral position, segregation, absence of ear reflex, and tremor. There is limited experience regarding cases of human overdosage, and treatment should be symptomatic and supportive.

biotransformation

Pantoprazole is extensively metabolized in the liver through the cytochrome P450 (CYP) system. The main metabolic pathway is demethylation, by CYP2C19, with subsequent sulfation; other metabolic pathways include oxidation by CYP3A4. There is no evidence that any of the pantoprazole metabolites have significant pharmacologic activity.

absorption

Pantoprazole is well absorbed. It undergoes little first-pass metabolism resulting in an absolute bioavailability of approximately 77%.

half life

1 hour

route of elimination

After administration of a single intravenous dose of 14C-labeled pantoprazole to healthy, normal metabolizer subjects, approximately 71% of the dose was excreted in the urine with 18% excreted in the feces through biliary excretion.

drug interactions

Atazanavir: This gastric pH modifier decreases the levels/effects of atazanavir

Cefditoren: Proton pump inhibitors such as pantoprazole may decrease the serum concentration of cefditoren. If possible, avoid use of cefditoren with proton pump inhibitors (PPIs). Consider alternative methods to minimize/control acid reflux (eg, diet modification) or alternative antimicrobial therapy if use of PPIs can not be avoided.

Clopidogrel: Pantoprazole may decrease serum concentrations of the active metabolite(s) of clopidogrel. Due to the possible risk for impaired clopidogrel effectiveness with this combination, clinicians should carefully consider the need for concurrent pantoprazole therapy in patients receiving clopidogrel. Monitor response to clopidogrel closely when using clopidogrel with pantoprazole. Whether there are differences among individual proton pump inhibitors is unclear. Other acid-lowering therapies (e.g., H2-receptor antagonists, antacids, etc.) do not appear to share this interaction with clopidogrel.

Dasatinib: Pantoprazole may decrease the serum level of dasatinib.

Enoxacin: Pantoprazole may decrease the absorption of enoxacin.

Indinavir: Omeprazole decreases the absorption of indinavir

Itraconazole: The proton pump inhibitor, pantoprazole, may decrease the absorption of itraconazole.

Ketoconazole: The proton pump inhibitor, pantoprazole, may decrease the absorption of ketoconazole.

Topotecan: The BCRP/ABCG2 inhibitor, Pantaprazole, may increase the bioavailability and serum concentration of oral Topotecan. Monitor for change in the therapeutic and adverse effects of Topotecan if Pantaprazole is initiated, discontinued or dose changed.