PREVACID SoluTab (lansoprazole) Delayed-Release Orally Disintegrating Tablets (十四)
razole (active ingredient) and the following inactive ingredients: mannitol, methacrylic acid, hydroxypropyl cellulose, lactose monohydrate-microcrystalline cellulose sphere, triethyl citrate, crospovidone, polyacrylate, magnesium carbonate, aspartame2, glyceryl monostearate, hypromellose, magnesium stearate, citric acid, titanium dioxide, talc, artificial strawberry flavor, polyethylene glycol, polysorbate 80 and ferric oxide.
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1 PREVACID 15-mg capsules only.
2 Phenylketonurics: Contains Phenylalanine 2.5 mg per 15 mg Tablet and 5.1 mg per 30 mg Tablet.
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12 CLINICAL PHARMACOLOGY
12.1 Mechanism of ActionPREVACID (lansoprazole) belongs to a class of antisecretory compounds, the substituted benzimidazoles, that suppress gastric acid secretion by specific inhibition of the (H+, K+)-ATPase enzyme system at the secretory surface of the gastric parietal cell. Because this enzyme system is regarded as the acid (proton) pump within the parietal cell, lansoprazole has been characterized as a gastric acid-pump inhibitor, in that it blocks the final step of acid production. This effect is dose-related and leads to inhibition of both basal and stimulated gastric acid secretion irrespective of the stimulus. Lansoprazole does not exhibit anticholinergic or histamine type-2 antagonist activity.
12.2 Pharmacodynamics
Antisecretory Activity: After oral administration, lansoprazole was shown to significantly decrease the basal acid output and significantly increase the mean gastric pH and percent of time the gastric pH was greater than 3 and greater than 4. Lansoprazole also significantly reduced meal-stimulated gastric acid output and secretion volume, as well as pentagastrin-stimulated acid output. In patients with hypersecretion of acid, lansoprazole significantly reduced basal and pentagastrin-stimulated gastric acid secretion. Lansoprazole inhibited the normal increases in secretion volume, acidity and acid output induced by insulin.
The intragastric pH results of a five-day, pharmacodynamic, crossover study of 15 mg and 30 mg of once daily lansoprazole are presented in Table 4:
Table 4: Mean Antisecretory Effects After Single and Multiple Daily PREVACID Dosing PREVACID
Baseline Value 15 mg 30 mg
Parameter Day 1 Day 5 Day 1 Day 5
Note: An intragastric pH of greater than 4 reflects a reduction in gastric acid by 99%
* (p<0.05) versus baseline only. † (p<0.05) versus baseline and lansoprazole 15 mg.
Mean 24 Hour pH 2.1 2.7* 4.0* 3.6† 4.9†
Mean Nighttime pH 1.9 2.4 3.0* 2.6 3.8†
% Time Gastric pH>3 18 33* 59* 51† 72†
% Time Gastric pH>4 12 22* 49* 41† 66†
After the initial dose in this study, increased gastric pH was seen within 1 to 2 hours with 30 mg of lansoprazole and 2 to 3 hours with 15 mg of lansoprazole. After multiple daily dosing, increased gastric pH was seen within the first hour post-dosing with 30 mg of lansoprazole and within 1 to 2 hours post-dosing with 15 mg of lansoprazole.
Acid suppression may enhance the effect of antimicrobials in eradicating Helicobacter pylori (H. pylori). The percentage of time gastric pH was elevated above 5 and 6 was eva luated in a crossover study of PREVACID given daily, twice daily and three times daily (Table 5).
Table 5: Mean Antisecretory Effects Afte |
