THE EFFECT OF RANITIDINE ON THE ABSORPTION KINETICS OF METRONIDAZOLE

THE EFFECT OF RANITIDINE ON THE ABSORPTION KINETICS OF METRONIDAZOLE

Abstract:

The effect of a singleoral dose of ranitidine I50mg was s t u d i e d on t h e a b s o r p t i o n and pharmacokinetic parameters of metronidazole following a s i n g l e o r al dose of 4OOmg in four h e a l t h y v o l u n t e e r s (age 28-35, weight 50-65kg) administered one hour a f t e r r a n i t i d i ne i n a c r o s s – o v e r s t u d y. The a d m i n i s t r a t i o n of r a n i t i d i n e l50mg an hour b e f o r e the dose of metronidazole did not a f f e ct s i g n i f i c a n t l y the mean a b s o r p t i o n and pharmacokinetic parameters of metronidazole ( p > 0 . 5 ) . Ranitidine i n c r e a s e d Kabs by 20.5%, t1 / 2 by 10.15%, Tiag by 60.8% and d e c r e a s e d Tmax and Cmax by 7% and 3,kh% r e s p e c t i v e ly ( i n a l l cases P > 0 . 0 5 ) . S i m i l a r l y , Kel and ClTBC were d e c r e a s e d by 8.11% and 1.1% (P> 0 . 1 and > 0.5 r e s p e c t i v e l y ) while t1/2, Vd and AUC were i n c r e a s e d by 8.26%, 6.8% and 1.92% r e s p e c t i v e l y ( P > 0 . 1 , > 0.5 and > 0 . 5 ) . S i m i l a r t o r e s u l t s obtained i n previous s t u d i e s, t h e r e were v a r i a t i o n s in t h e plasma c o n c e n t r a t i o n s and p h a r m a c o k i n e t i c parameters of metronidazole in man. The e f f e c t of r a n i t i d i n e on t h e k i n e t i c s of metronidazole was h i g h l y v a r i a b l e and in some v o l u n t e e r s it was s u b s t a n t i a l . It i s concluded t h a t d e s p i t e the l a r ge i n t e r – i n d i v i d u a l d i f f e r e n c e s , r a n i t i d i n e does not a l t er the mean pharmacokinetics of metronidazole in man, but that simply using the mean data for comparison could be misleading

THE EFFECT OF RANITIDINE ON THE ABSORPTION KINETICS OF METRONIDAZOLE