Effect of gastric acidity on enoxacin absorption.
The effect of gastric acidity on the oral absorption of the quinolone antibiotic enoxacin was evaluated in 12 healthy volunteers. In a randomized, crossover design, single 400 mg oral enoxacin doses were administered on four occasions: alone, after 50 mg intravenous ranitidine, after 2 micrograms/kg subcutaneous pentagastrin, and after combined ranitidine and pentagastrin treatment. Gastric pH was monitored by radiotelemetry capsule for 4 hours after enoxacin administration. Ranitidine pretreatment reduced enoxacin oral bioavailability by an average of 26%. This effect was abolished when pentagastrin was used to maintain low gastric pH. Thus the ranitidine-induced decrease in enoxacin oral bioavailability probably results from a decrease in gastric acidity rather than from an interaction with ranitidine itself.
Lebsack
M E
ME
Clinical Pharmacology Department, Parke-Davis Pharmaceutical Research Division, Warner-Lambert Company, Ann Arbor, Mich.
Nix
D
D
Ryerson
B
B
Toothaker
R D
RD
Welage
L
L
Norman
A M
AM
Schentag
J J
JJ
Sedman
A J
AJ
D000284:Administration, Oral; D000293:Adolescent; D000328:Adult; D001682:Biological Availability; D004347:Drug Interactions; D015365:Enoxacin / Q000493:pharmacokinetics*; D005260:Female; D005744:Gastric Acid / Q000502:physiology*; D005745:Gastric Acidity Determination; D006801:Humans; D007262:Infusions, Intravenous; D007279:Injections, Subcutaneous; D007408:Intestinal Absorption / Q000187:drug effects; D008297:Male; D010418:Pentagastrin / Q000494:pharmacology; D011899:Ranitidine / Q000494:pharmacology
D015365:Enoxacin; D011899:Ranitidine; D010418:Pentagastrin