Lansoprazole

Absorption

The oral bioavailability of lansoprazole is reported to be 80-90% and the peak plasma concentration(Cmax) is achieved about 1.7 hours after oral dosing. Food reduces the absorption of lansoprazole (both Cmax and AUC are reduced by 50-70%); therefore, patients should be instructed to take lansoprazole before meals.

Toxicity

The most commonly reported adverse events occurring more frequently in lansoprazole treated patients compared to placebo include abdominal pain, constipation, diarrhea, and nausea. Lansoprazole is classified as Pregnancy Category B. Although there are animal studies that suggest lansoprazole does not cause harm to the fetus, there is still a paucity of human data. Hence, lansoprazole should only be administered to pregnant women if other options with more safety data have been exhausted. It is unknown if lansoprazole is excreted in human breast milk. It is worth mentioning that lansoprazole has been used safely in infants, and is therefore likely safe to use during breastfeeding.

Description

Lansoprazole is the second proton pump inhibitor approved as an antiulcer agent for the short term treatment of duodenal ulcer and gastroesophageal reflux disease. It is a proton-pump inhibitor that reduces the stomach’s ability to produce acids. It is also used to treat gastric ulcers and, along with antibiotics, to combat Helicobacter pylori infections. It is in the same drug class as omeprazole (Prilosec), another widely used heartburn remedy.

Chemical properties

White Crystalline Powder

The Uses of Lansoprazole

Lansoprazole is used as a gastric proton pump inhibitor. Treatment of gastroesophageal reflux disease (GERD), erosive esophagitis, duodenal ulcers, Helicobacter pylori (H. pylori) infections,stomach ulcers, prevention of stomach ulcers in those people taking non-steroidal anti-inflammatory drugs (NSAIDs)

Indications

Lansoprazole is used to reduce gastric acid secretion and is approved for short term treatment of active gastric ulcers, active duodenal ulcers, erosive reflux oesophagitis, symptomatic gastroesophageal reflux disease, and non-steroidal anti-inflammatory drug (NSAID) induced gastric and duodenal ulcers. It may be used in the maintenance and healing of several gastric conditions including duodenal ulcers, NSAID related gastric ulcers, and erosive esophagitis. Lansoprazole prevents recurrence of gastric ulcers in patients who have a documented history of gastric ulcers who also use NSAIDs chronically. Predictably, it is also useful in the management of hypersecretory conditions including Zollinger-Ellison syndrome. Lansoprazole is effective at eradicating H. pylori when used in conjunction with amoxicillin and clarithromycin (triple therapy) or with amoxicillin alone (dual therapy).

Definition

ChEBI: Lansoprazole is a member of benzimidazoles, a member of pyridines and a sulfoxide. It has a role as an EC 3.6.3.10 (H(+)/K(+)-exchanging ATPase) inhibitor and an anti-ulcer drug.

brand name

Prevacid (TAP);Ogast;Lanzor.

Biological Activity

Lansoprazole is a proton pump inhibitor that inhibits the H+/K+-ATPase. It inhibits K+ and H+ accumulation in gastric microsomes in a concentration-dependent manner (IC50s = 6.3 and 7.0 μM, respectively) and inhibits H+/K+-ATPase activity by approximately 60% when used at a concentration of 10 μM. Lansoprazole inhibits the H+/K+-ATPase in parietal cells, thus inhibiting gastric acid secretion and increasing intragastric pH. It is a substituted benzimidazole that binds covalently to proton pumps, providing complete and prolonged inhibition of acid secretion.

Pharmacokinetics

Lansoprazole decreases gastric acid secretion by targeting H+,K+-ATPase, which is the enzyme that catalyzes the final step in the acid secretion pathway in parietal cells. Conveniently, lansoprazole administered any time of day is able to inhibit both daytime and nocturnal acid secretion. The result is that lansoprazole is effective at healing duodenal ulcers, reduces ulcer-related pain, and offers relief from symptoms of heartburn Lansoprazole also reduces pepsin secretion, making it a useful treatment option for hypersecretory conditions such as Zollinger-Ellison syndrome.

Metabolism

Lansoprazole is predominantly metabolized in the liver by CYP3A4 and CYP2C19. The resulting major metabolites are 5-hydroxy lansoprazole and the sulfone derivative of lansoprazole.