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Protonix I.V.

Clinical Pharmacology
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Clinical Pharmacology

Pantoprazole is a proton pump inhibitor (PPI) that suppresses the final step in gastric acid production by covalently binding to the (H+, K+)-ATPase enzyme system at the secretory surface of the gastric parietal cell. This effect leads to inhibition of both basal and stimulated gastric acid secretion irrespective of the stimulus. The binding to the (H+, K+)-ATPase results in a duration of antisecretory effect that persists longer than 24 hours for all doses tested.

Antisecretory Activity

The magnitude and time course for inhibition of pentagastrin-stimulated acid output (PSAO) by single doses (20 to 120 mg) of PROTONIX I.V. for Injection were assessed in a single-dose, open-label, placebo-controlled, dose-response study. The results of this study are shown in the table below. Healthy subjects received a continuous infusion for 25 hours of pentagastrin (PG) at 1 µg/kg/h, a dose known to produce submaximal gastric acid secretion. The placebo group showed a sustained, continuous acid output for 25 hours, validating the reliability of the testing model. PROTONIX I.V. for Injection had an onset of antisecretory activity within 15 to 30 minutes of administration. Doses of 20 to 80 mg of PROTONIX I.V. for Injection substantially reduced the 24-hour cumulative PSAO in a dose-dependent manner, despite a short plasma elimination half-life. Complete suppression of PSAO was achieved with 80 mg within approximately 2 hours and no further significant suppression was seen with 120 mg. The duration of action of PROTONIX I.V. for Injection was 24 hours.

Gastric Acid Output (mEq/hr, Mean ± SD) and Percent Inhibitiona (Mean ± SD) of Pentagastrin-Stimulated Acid Output Over 24 Hours Following a Single Dose of PROTONIX I.V. for Injectionb in Healthy Subjects

  2 hours 4 hours 12 hours 24 hours
Treatment Dose Acid Output % Inhibition Acid Output % Inhibition Acid Output % Inhibition Acid Output % Inhibition
0 mg (Placebo, n=4) 39 ± 21 NA 26±14 NA 32 ± 20 NA 38 ± 24 NA
20 mg (n=4-6) 13 ± 18 47 ± 27 6 ± 8 83 ± 21 20 ± 20 54 ± 44 30 ±23 45 ± 43
40 mg (n=8) 5 ± 5 82 ± 11 4 ± 4 90 ± 11 11 ± 10 81 ± 13 16 ± 12 52 ± 36
80 mg (n=8) 0.1 ± 0.2 96 ± 6 0.3 ± 0.4 99 ± 1 2 ± 2 90 ± 7 7 ± 4 63 ± 18
a Compared to individual subject baseline prior to treatment with PROTONIX I.V. for Injection. NA = not applicable.
b Inhibition of gastric acid output and the percent inhibition of stimulated acid output in response to PROTONIX I.V. for Injection may be higher after repeated doses.

Brand Name: Protonix I.V.
Generic Name: Pantoprazole Sodium
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