Lansoprazole
Introduction
Lansoprazole is a proton pump inhibitor (PPI) that suppresses gastric acid secretion by specific inhibition of the H+/K+-ATPase in the gastric parietal cell. By acting specifically on the proton pump, lansoprazole blocks the final step in acid production, thus reducing gastric acidity. This effect is dose-related and leads to inhibition of both basal and stimulated acid secretion irrespective of the stimulus.
Pharmacology
Lansoprazole belongs to a class of antiseptic drugs known as proton pump inhibitors (PPIs). Other drugs in the same class include omeprazole, pantoprazole, and rabeprazole. Lansoprazole is used for treating ulcers of the stomach and duodenum, gastroesophageal reflux disease (GERD) and Zollinger-Ellison Syndrome.
Mechanism of Action
Lansoprazole is a prodrug that is converted to the active form in the acidic environment of the parietal cells. The active form of lansoprazole specifically binds to the H+/K+ ATP pump and inhibits the activity of the pump. This results in the blockage of the final step of gastric acid production and reduces gastric acidity.
Pharmacokinetics
The absorption of lansoprazole is rapid, with the peak plasma concentration occurring within 1.7 hours. The bioavailability of lansoprazole is over 80%. The drug is extensively metabolized in the liver. The elimination half-life of lansoprazole is approximately 1.5 hours. The drug is excreted in the urine and feces.
Clinical Use
Lansoprazole is used for the treatment of peptic ulcer disease, gastroesophageal reflux disease (GERD), and Zollinger-Ellison syndrome. It is also used for the treatment of Helicobacter pylori infection in combination with antibiotic therapy. Lansoprazole is also used for the prevention of gastric ulcers induced by non-steroidal anti-inflammatory drugs (NSAIDs).
Side Effects
The most common side effects associated with lansoprazole use include headache, abdominal pain, constipation, diarrhea, and nausea. Rarely, lansoprazole may cause pancreatitis, liver disease, fractures, and low magnesium levels.
Drug Interactions
Lansoprazole can interact with other medications such as warfarin, digoxin, and theophylline. It may also interact with certain antifungal drugs, HIV medications, and certain antibiotics.
Contraindications
Lansoprazole is contraindicated in patients with known hypersensitivity to any component of the formulation or to substituted benzimidazoles. It is also contraindicated in patients receiving rilpivirine-containing products.