Omeprazole is widely used in the treatment
of the gastroesophageal ref lux and peptic ulcer
diseases. It inhibits the proton pump in the gastric
parietal cells. Proton pumps also exist in kidney
nephron. However, the renal effects of omeprazole
have not been elucidated yet. This study
investigates the effects of omeprazole intramuscular
administration for four weeks on mean
arterial pressure (MAP), renal blood flow (RBF),
renal vascular reactivity to both phenylephrine
(PHE1 and dopamine (DA) and on tubular excretion.
Kidneys were also examined for histopathological
changes. The study included four
groups of rat (n=6), the second and the fourth
served as control and were injected with the
vehicle for 4 weeks. The first and the third
were inejcted with omeprazole (0.2 mg/kg) for
the same time period. Chronic omeprazole
administration slightly reduced P.BF (from 12.1 +
0.3 to 11.2 + 0.4 ml/min) but significantly reduced
the responsNeness of the renal vasculature to the
vasoconstrictor PEE and the vasodilator DA.
Urinary pH was increased (6.8 to 7.6) and urine
flow rate was slightly decreased (from 50+6 to
38+5 tit/min). Na.- and K excretion was impaired
(from 110+11 to 72+9 mmol/min for Na+ and
from 69+6 to 47+7 mmol/min for K+). Albumin
traces were (-fleeted in urine. Histopathological
examination 'i.owed evidence of interstitial nephritis.
Thus chronic use of omeprazole may be
associated • fth renal damage and impaired kidney
functions.
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