PROTON PUMP INHIBITORS

 

INTRODUCTION: Proton pump inhibitors act by blocking the enzyme responsible for secreting hydrochloric acid in the stomach. They are drugs of choice for the short-term therapy of PUD and GERD. Proton pump inhibitors (PPIs) reduce acid secretion in the stomach by binding irreversibly to K⁺/H⁺ATPase, the enzyme that acts as a pump to release acid (also called H⁺, or protons) onto the surface of the GI mucosa. The PPIs reduce acid secretion to a greater extent than the H2-receptor antagonists and have a longer duration of action.  PPIs heal more than 90% of duodenal ulcers within 4 weeks and about 90% of gastric ulcers in 6 to 8 weeks. Several days of PPI therapy may be needed before patients gain relief from ulcer pain. Beneficial effects continue for 3 to 5 days after the drugs have been stopped. These drugs are used only for the short-term control of peptic ulcers and GERD: Peptic ulcer disease

The typical length of therapy is 4 weeks. Omeprazole and lansoprazole are used concurrently with antibiotics to eradicate H. pylori. Esomeprazole and pantoprazole offer the convenience of once-a-day dosing.

OMEPRAZOLE

Therapeutic Class: Antiulcer drug

Pharmacologic Class: Proton pump inhibitor

ACTIONS AND USES: Omeprazole was the first PPI to be approved for PUD: Both prescription and OTC forms are available. Its pharmacodynamics is discussed in the introduction. Although this drug can take 2 hours to reach therapeutic levels, its effects last up to 72 hours. It is used for the short-term, 4- to 8-week therapy of active peptic ulcers and GERD. Most patients are symptom free after 2 weeks of therapy. It is used for longer periods in patients who have chronic hypersecretion of gastric acid, a condition known as Zollinger–Ellison syndrome.

It is the most effective drug for this syndrome. Omeprazole is available only in oral form.

ADMINISTRATION ALERTS: If possible, administer before breakfast on an empty stomach. It may be administered with antacids. Capsules and tablets should not be chewed, divided, or crushed.

Pregnancy category C. [read about drug use inrelation to pregnancy]

ADVERSE EFFECTS: Adverse effects are generally minor and include headache, nausea, diarrhea, rash, and abdominal pain. Although rare, blood disorders may occur, causing unusual fatigue and weakness. Therapy is generally limited to 2 months. Atrophic gastritis and hypomagnesemia have been reported rarely with prolonged treatment with PPIs.

CONTRAINDICATIONS: The only contraindication is hypersensitivity to the drug. OTC use is not approved for patients under 18 years of age.

INTERACTIONS:

Drug–Drug: Concurrent use with diazepam, phenytoin, and central nervous system (CNS) depressants may cause increased blood levels of these drugs. Concurrent use with warfarin may increase the likelihood of bleeding. Alcohol can aggravate the stomach mucosa and decrease the effectiveness of omeprazole.

Lab Tests: Omeprazole may increase values for ALT, AST, and serum alkaline phosphatase.

Herbal/Food: Ginkgo and St. John’s wort may decrease the plasma concentration of omeprazole.

RELATED;

1. PEPTIC ULCER DISEASE

2.  ANTIACIDS

REFERENCES