Acid suppression by omeprazole does not affect orally administered metronidazole bioavailability and metabolism in healthy male volunteers.
BACKGROUND
The addition of omeprazole to classical triple therapy for eradication of H. pylori may enhance compliance through reducing ulcer symptoms and side-effects. The aim of this study was to investigate the effects of a 5-day administration of omeprazole on metronidazole pharmacokinetics.


METHODS
Fourteen healthy male volunteers were selected. The study had an open, randomized, two-period crossover design with a 21-day washout period between the phases. Plasma concentrations of metronidazole and its hydroxy-metabolite were measured by reversed-phase HPLC with ultraviolet detection.


RESULTS
Administration of omeprazole did not affect the pharmacokinetic parameters of orally administered metronidazole.


CONCLUSIONS
Our results indicate that short-term treatment with omeprazole in healthy volunteers does not alter the extent or the rate of metronidazole absorption, and does not affect metronidazole clearance.
Clinical Pharmacology Unit, São Francisco University Medical School, Bragança Paulista, SP, Brazil.
F L
FL
David
C M
CM
Da Silva
F D
FD
Mendes
J G
JG
Ferraz
M N
MN
Muscara
H
H
Moreno
G
G
De Nucci
J
J
Pedrazzoli
D000284:Administration, Oral; D000328:Adult; D000897:Anti-Ulcer Agents / Q000008:administration & dosage / Q000494:pharmacology* / Q000627:therapeutic use; D000994:Antitrichomonal Agents / Q000009:adverse effects / Q000493:pharmacokinetics* / Q000627:therapeutic use; D001682:Biological Availability; D018592:Cross-Over Studies; D004347:Drug Interactions; D005744:Gastric Acid / Q000378:metabolism*; D016481:Helicobacter Infections / Q000188:drug therapy; D016480:Helicobacter pylori; D006801:Humans; D008297:Male; D008795:Metronidazole / Q000009:adverse effects / Q000493:pharmacokinetics* / Q000627:therapeutic use; D009853:Omeprazole / Q000008:administration & dosage / Q000494:pharmacology* / Q000627:therapeutic use
D000897:Anti-Ulcer Agents; D000994:Antitrichomonal Agents; D008795:Metronidazole; D009853:Omeprazole