Which of the following drug is wrong about proton pump inhibitors (AIIMS Nov 2010)
|D||High first pass metabolism|
a. Proton pump inhibitors are long acting sulphonamide derivatives. These act by blocking the enzyme Na+K+ ATPase. The drugs are well absorbed orally and in the apex of parietal canaliculi; these drugs get converted into their active moiety.
b. The drugs have high first pass metabolism. They form a covalent bond with their target. Perhaps, that is the reason of their long duration of action.
c. These drugs produce prolonged acid suppression and bring the pH of stomach to nearly zero. This is the result of virtual 100% acid suppression. The drugs though have an average half life of 1 hour; but effect of acid suppression lasts for about 2 days or so. Drugs are very well tolerated.
d. Usual side effects are nausea, abdominal pain and very rarely pneumonitis due to prolonged acid suppression. Sometimes, breakthrough pain occurs during therapy. This can be managed by antacids (BG Katzung’ 10th Edition, 2010).
(Remember: PPI are known as HIT & RUN drugs because of long duration of action, bind irreversibly to Na+K+ ATPase)