Zegerid with Magnesium Hydroxide (Page 2 of 6)

Enterochromaffin-like (ECL) Cell Effects

In 24-month carcinogenicity studies in rats, a dose-related significant increase in gastric carcinoid tumors and ECL cell hyperplasia was observed in both male and female animals (see PRECAUTIONS, Carcinogenesis, Mutagenesis, Impairment of Fertility). Carcinoid tumors have also been observed in rats subjected to fundectomy or long-term treatment with other proton pump inhibitors or high doses of H2-receptor antagonists. Human gastric biopsy specimens have been obtained from more than 3000 patients treated with omeprazole in long-term clinical trials. The incidence of ECL cell hyperplasia in these studies increased with time; however, no case of ECL cell carcinoids, dysplasia, or neoplasia has been found in these patients. These studies are of insufficient duration and size to rule out the possible influence of long-term administration of omeprazole on the development of any premalignant or malignant conditions.

Serum Gastrin Effects

In studies involving more than 200 patients, serum gastrin levels increased during the first 1 to 2 weeks of once-daily administration of therapeutic doses of omeprazole in parallel with inhibition of acid secretion. No further increase in serum gastrin occurred with continued treatment. In comparison with histamine H2-receptor antagonists, the median increases produced by 20 mg doses of omeprazole were higher (1.3 to 3.6 fold vs. 1.1 to 1.8 fold increase). Gastrin values returned to pretreatment levels, usually within 1 to 2 weeks after discontinuation of therapy.

Other Effects

Systemic effects of omeprazole in the CNS, cardiovascular, and respiratory systems have not been found to date. Omeprazole, given in oral doses of 30 or 40 mg for 2 to 4 weeks, had no effect on thyroid function, carbohydrate metabolism, or circulating levels of parathyroid hormone, cortisol, estradiol, testosterone, prolactin, cholecystokinin, or secretin.

No effect on gastric emptying of the solid and liquid components of a test meal was demonstrated after a single dose of omeprazole 90 mg. In healthy subjects, a single I.V. dose of omeprazole (0.35 mg/kg) had no effect on intrinsic factor secretion. No systematic dose-dependent effect has been observed on basal or stimulated pepsin output in humans. However, when intragastric pH is maintained at 4.0 or above, basal pepsin output is low, and pepsin activity is decreased.

As do other agents that elevate intragastric pH, omeprazole administered for 14 days in healthy subjects produced a significant increase in the intragastric concentrations of viable bacteria. The pattern of the bacterial species was unchanged from that commonly found in saliva. All changes resolved within three days of stopping treatment.

The course of Barrett’s esophagus in 106 patients was evaluated in a U.S. double-blind controlled study of omeprazole 40 mg b.i.d. for 12 months followed by 20 mg b.i.d. for 12 months or ranitidine 300 mg b.i.d. for 24 months. No clinically significant impact on Barrett’s mucosa by antisecretory therapy was observed. Although neosquamous epithelium developed during antisecretory therapy, complete elimination of Barrett’s mucosa was not achieved. No significant difference was observed between treatment groups in development of dysplasia in Barrett’s mucosa and no patient developed esophageal carcinoma during treatment. No significant differences between treatment groups were observed in development of ECL cell hyperplasia, corpus atrophic gastritis, corpus intestinal metaplasia, or colon polyps exceeding 3 mm in diameter (see also CLINICAL PHARMACOLOGY, Enterochromaffin-like (ECL) Cell Effects).

Clinical Studies

Duodenal Ulcer Disease

Active Duodenal Ulcer – In a multicenter, double-blind, placebo controlled study of 147 patients with endoscopically documented duodenal ulcer, the percentage of patients healed (per protocol) at 2 and 4 weeks was significantly higher with omeprazole 20 mg once a day than with placebo (p ≤ 0.01). (See Table 2.)

Table 2: Treatment of Active Duodenal Ulcer; % of Patients Healed
Omeprazole 20 mg a.m. (n = 99) Placebo a.m. (n = 48)

* (p ≤ 0.01)

Week 2 41* 13
Week 4 75* 27

Complete daytime and nighttime pain relief occurred significantly faster (p ≤ 0.01) in patients treated with omeprazole 20 mg than in patients treated with placebo. At the end of the study, significantly more patients who had received omeprazole had complete relief of daytime pain (p ≤ 0.05) and nighttime pain (p ≤ 0.01).

In a multicenter, double-blind study of 293 patients with endoscopically documented duodenal ulcer, the percentage of patients healed (per protocol) at 4 weeks was significantly higher with omeprazole 20 mg once a day than with ranitidine 150 mg b.i.d. (p < 0.01). (See Table 3.)

Table 3: Treatment of Active Duodenal Ulcer; % of Patients Healed
Omeprazole 20 mg a.m. (n = 145) Ranitidine 150 mg b.i.d. (n = 148)

* (p < 0.01)

Week 2 42 34
Week 4 82* 63

Healing occurred significantly faster in patients treated with omeprazole than in those treated with ranitidine 150 mg b.i.d. (p < 0.01).

In a foreign multinational randomized, double-blind study of 105 patients with endoscopically documented duodenal ulcer, 40 mg and 20 mg of omeprazole were compared to 150 mg b.i.d. of ranitidine at 2, 4 and 8 weeks. At 2 and 4 weeks both doses of omeprazole were statistically superior (per protocol) to ranitidine, but 40 mg was not superior to 20 mg of omeprazole, and at 8 weeks there was no significant difference between any of the active drugs. (See Table 4.)

Table 4: Treatment of Active Duodenal Ulcer; % of Patients Healed
Omeprazole 40 mg (n = 36) Omeprazole 20 mg (n = 34) Ranitidine 150 mg b.i.d. (n = 35)

*(p ≤ 0.01)

Week 2 83* 83* 53
Week 4 100* 97* 82
Week 8 100 100 94

Gastric Ulcer

In a U.S. multicenter, double-blind, study of omeprazole 40 mg once a day, 20 mg once a day, and placebo in 520 patients with endoscopically diagnosed gastric ulcer, the following results were obtained. (See Table 5.)

Table 5: Treatment of Gastric Ulcer; % of Patients Healed (All Patients Treated)
Omeprazole 40 mg q.d. (n = 214) Omeprazole 20 mg q.d. (n = 202) Placebo (n = 104)

** (p < 0.01) omeprazole 40 mg or 20 mg versus placebo

+ (p < 0.05) omeprazole 40 mg versus 20 mg

Week 4 55.6** 47.5** 30.8
Week 8 82.7**,+ 74.8** 48.1

For the stratified groups of patients with ulcer size less than or equal to 1 cm, no difference in healing rates between 40 mg and 20 mg was detected at either 4 or 8 weeks. For patients with ulcer size greater than 1 cm, 40 mg was significantly more effective than 20 mg at 8 weeks.

In a foreign, multinational, double-blind study of 602 patients with endoscopically diagnosed gastric ulcer, omeprazole 40 mg once a day, 20 mg once a day, and ranitidine 150 mg twice a day were evaluated. (See Table 6.)

Table 6: Treatment of Gastric Ulcer; % of Patients Healed (All Patients Treated)
Omeprazole 40 mg q.d. (n = 187) Omeprazole 20 mg q.d. (n = 200) Ranitidine 150 mg b.i.d. (n = 199)

**(p < 0.01) Omeprazole 40 mg versus ranitidine

++(p < 0.01) Omeprazole 40 mg versus 20 mg

Week 4 78.1**,++ 63.5 56.3
Week 8 91.4**,++ 81.5 78.4

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