Evaluation of the pharmacokinetics and pharmacodynamics of intravenous lansoprazole

To compare the pharmacokinetics and pharmacodynamics of lansoprazole 30 mg administered intravenously in 0.9% NaCl or in polyethylene glycol, or orally.

Twenty-nine subjects received lansoprazole orally on days 1-7 and intravenous lansoprazole in NaCl on days 8-14. Blood samples were collected on days 1, 7, 8 and 14. Fasting basal acid output and pentagastrin-stimulated maximal acid output were determined on days -1, 8, 9 and 15. Thirty-six different subjects received one of four regimen sequences: intravenous lansoprazole in NaCl, intravenous in polyethylene glycol, per orally, or intravenous placebo, each for 5 days. Twenty-four hour intragastric pH was recorded on days 1 and 5.

Intravenous and per oral lansoprazole for 7 days produced equivalent basal acid output and maximal acid output suppression. Pharmacokinetics and mean pH values with intravenous lansoprazole in NaCl or polyethylene glycol were equivalent. Both produced mean pH and percentages of time pH above 3, 4, 5 and 6 that were significantly greater than did per orally.

Intravenous lansoprazole inhibits acid secretion as effectively in NaCl as in polyethylene glycol, and its onset of action is faster than per oral lansoprazole.