Ranitidine pharmacokinetics

Rendic, S., Ruf, S., Weher, P. and Kajfez, F. (1984). Cimetidine and ranitidine Their interaction with human and pig liver microsomes and with purified cytochrome P-450. Eta J. Drug Metab. Pharmacokinet. 9 195-200. 

Toon S, Hopkins KJ, Garstang FM, et al. Comparative effects of ranitidine and cimetidine on the pharmacokinetics and pharmacodynamics of warfarin. Eur ] Clin Pharmacol 1987 32 165-72. 

Children-The safety and effectiveness of ranitidine have been established in children from 1 month to 16 years of age. There is insufficient information about the pharmacokinetics of ranitidine in neonatal patients under 1 month of age to make dosing recommendations. Do not give OTC ranitidine to children under 12 years of age unless directed by physician. 

Clinicians should be aware of a few drug interactions with Zolpidem. Flumazenil acts as an antagonist to the hypnotic effects of zolpidem. There is decreased alertness when zolpidem is combined with cimetidine. There is an increase in anterograde amnesia in volunteers treated with a combination of imipramine and zolpidem. Haloperidol, ranitidine, chlorpromazine, warfarin, and digoxin, along with cimetidine and flumazenil, do not alter the pharmacokinetics of zolpidem (Salva and Costa, 1995). 

Sanders, A. B., and Moore, J. G. Intragastric pH and pharmacokinetics of intravenous ranitidine during sinusoidal and constant-rate infusions. Chronobiol. Int. 8 267—276, 1991. 

S.R. Smith, and M.J. Kendall, Ranitidine versus cimetidine A comparison of their potential to cause clinically important drug interactions. Clin. Pharmacokinet. 15 44-56, 1988. 

Miller R. Pharmacokinetics and bioavailability of ranitidine in humans. J Pharm Sci 1984 73 1376-9. 

M, Muirhead, F, Bochnet and A. Somogyi, Pharmacokinetic drug interactions between triamterene and ranitidine in humans Alterations in renal and hepatic clearances and gastrointestinal absorption, /. Pharmacd. Exp. Ther., 244 734-739 (1988). 

Blouin RA, Kneer J, Ambros RJ, Stoeckel K. Influence of antacid and ranitidine on the pharmacokinetics of oral cefetamet pivoxil. Antimicrob Agents Chemother 1990 34(9) 1744-8. 

Kirch W, Janisch HD, Heidemann H, Ramsch K, Ohnhaus EE. Einfluss von Cimetidin und Ranitidin auf Pharmakokinetik und antihypertensiven Effect von Nifedipin. [Effect of cimetidine and ranitidine on the pharmacokinetics and anti-hypertensive effect of nifedipine.] Dtsch Med Wochenschr 1983 108(46) 1757-61. 

In the same way that pharmacokinetic studies have been used to ascertain whether co-administration of an inhibitor of CYP3A4 can lead to cardiotoxicity, similar studies have been carried out to indicate whether the co-administration of an inhibitor can enhance a limited sedative effect. Healthy subjects took a single dose of racemic chlorphenamine 4 mg on two separate occasions the second occasion coincided with the sixth day of dosing with ranitidine 75 mg bd for 8 days. Serum concentrations and urinary excretion of chlorphenamine were not altered, and so it was considered unlikely that co-administration with ranitidine would enhance the potential of chlorphenamine to cause drowsiness (5). 

Koch KM, O Connor-Semmes RL, Davis IM, Yin Y. Stereoselective pharmacokinetics of chlorpheniramine and the effect of ranitidine. J Pharm Sci 1998 87(9) 1097-100. 

The available data on a possible interaction between histamine H2 receptor antagonists and ciclosporin are inconclusive. Whereas neither cimetidine nor ranitidine significantly altered ciclosporin pharmacokinetics, there was an increase in serum creatinine concentration in patients taking both ciclosporin and cimetidine, but not ranitidine. The clinical significance of this interaction is probably limited, and it has been attributed to competition of cimetidine with creatinine for tubular secretion (251). 

Webster LK, Mihaly GW, Jones DB, Smallwood RA, Phillips JA, Vajda FJ. Effect of cimetidine and ranitidine on carbamazepine and sodium valproate pharmacokinetics. Eur J Chn Pharmacol 1984 27(3) 341-3. 

Sutherland DL, Remillard AJ, Haight KR, Brown MA, Old L. The influence of cimetidine versus ranitidine on doxepin pharmacokinetics. Eur J Chn Pharmacol 1987 32(2) 159-64. 

Fraser IM, Buttoo KM, Walker SE, Stewart JH, Babul N. Effects of cimetidine and ranitidine on the pharmacokinetics of a chronotherapeutically formulated once-daily theophylline preparation (Uniphyl). Clin Ther 1993 15(2) 383-93. 

Winship LC, McKenney JM, Wright JT Jr, Wood JH, Goodman RP. The effect of ranitidine and cimetidine on single-dose diltiazem pharmacokinetics. Pharmacotherapy 1985 5(1) 16-19. 

Muck W, Wingender W, Seiberling M, Woelke E, Ramsch KD, Kuhlmann J. Influence of the H2-receptor antagonists cimetidine and ranitidine on the pharmacokinetics of nimodipine in healthy volunteers. Eur J Chn Pharmacol 1992 42(3) 325-8. 

In a randomized, placebo-controlled study of the effects of cimetidine and ranitidine on the pharmacokinetics and pharmacodynamics of a single dose of dofetilide 500 micrograms in 20 healthy men, ranitidine 150 mg bd did not affect the pharmacokinetics or pharmacodynamics of dofetilide, but there was a dose-dependent increase in exposure to dofetilide with cimetidine (61). With cimetidine 100 and 400 mg bd the AUC of dofetilide increased by 11 and 48%, the maximum plasma dofetilide concentration increased by 11 and 29%, renal clearance fell by 13 and 33%, and non-renal clearance by 5 and 21% dofetilide-induced prolongation of the QT interval was increased by 22 and 33%. The authors suggested that cimetidine inhibited renal tubular dofetilide secretion,... 

Misiak PM, Eldon MA, Toothaker RD, Sedman AJ. Effects of oral cimetidine or ranitidine on the pharmacokinetics of intravenous enoxacin. J Clin Pharmacol 1993 33(l) 53-6. 

Orenstein SR, Blumer JL, Faessel HM, McGuire JA, Fung K, Li BU, Lavine JE, Grunow JE, Treem WR, Ciociola AA. Ranitidine, 75 mg, over-the-counter dose pharmacokinetic and pharmacodynamic effects in children with symptoms of gastro-oesophageal reflux. Aliment Pharmacol Ther 2002 16(5) 899-907. 

Roxithromycin did not alter the pharmacokinetics of carbamazepine (15) or interact with warfarin, ranitidine, or antacids containing hydroxides of aluminium and magnesium (1). 

Pharmacokinetics All oral H -receptor antagonists are rapidly absorbed within 1 to 3 hours. Oral bioavailability is lower for ranitidine, cimetidine, and famotidine than for nizatidine. This is because ranitidine, cimetidine, and famotidine are incompletely absorbed and undergo first-pass hepatic metabolism. All of the Hj-receptor antagonists are eliminated via renal filtration and secretion. For this reason, the Hj-receptor antagonist T A may be increased in patients with renal dysfunction. 

This variability in response to the H2 antagonists probably reflects the variable and relatively poor oral bioavailability of these drugs in horses. In one study of five horses, the mean oral bioavailability of cimetidine, ranitidine and famotidine were 30%, 13% and 24%, respectively (Duran Ravis 1993). In another report, the mean oral bioavailability of cimetidine was 14% (range 7-22%) (Sams et al 1997). When administered p.o. at 3.3mg/kg, cimetidine could not be detected in plasma (Smyth et al 1990). Pharmacokinetic studies of ranitidine in six foals and six adult horses revealed a mean oral bioavailability of 38% in foals and 27% in adult horses. The half-life of cimetidine ranges from 1 to 2.2 h (Sams et al 1997, Smyth et al... 

Roberts CJ. Clinical pharmacokinetics of ranitidine. Clinical Pharmacokinetics, 1984, 9 211-221. 

The H2-receptor antagonists inhibit acid production by reversibly competing with histamine for binding to H2 receptors on the basolateral membrane of parietal cells. Four different H2-receptor antagonists, which differ mainly in their pharmacokinetics and propensity to cause drug interactions, are available in the United States cimetidine (Tagamet), ranitidine (Zantac), famotidine (Pepcid), and nizatidine (Axid). These drugs are less potent than proton-pump... 

Rustum, A.M. Rapid and sensitive HPLC determination of ranitidine in plasma. Application to pharmacokinetics study. J.Liq.Chromatogr., 1988, 11, 2315-2335... 

Smith, M.S. Oxford, J. Evans, M.B. Improved method for the separation of ranitidine and its metabolites based on supercritical fluid chromatography. J.Chromatogr.A, 1994, 683, 402-406 [SFC] Stiles, M.L. Allen, L.V., Jr. Prince, S. Stability of ranitidine hydrochloride during simulated home care use. Am.J.Hosp.Pharm., 1994, 51, 1706-1707 [stability-indicating ii jections saline 5% dextrose] Suttle, A.B. Brouwer, K.L.R. Bile flow but not enterohepatic recirculation influences the pharmacokinetics of ranitidine in the rat. Drug Metab.Dispos., 1994,22, 224-232 [serum bile pharmacokinetics procaine (IS) LOQ 75 ng/mL (serum) LOQ 500 ng/mL (bile)]... 

Reviews of ranitidine continue to substantiate its clinical efficacy and selectivity of action. " A multicenter trial in America has been assessed. Drug interactions, pharmacodynamics and pharmacokinetics of ranitidine and clmetldine have been compared. ... 

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