Metronidazole bioavailability

The bioavailability of a single 500-mg dose of metronidazole in 5 healthy subjeets was not significantly changed by 30 mL of a kaolin-pectin antid-iarrhoeal mixture. However, a 14.5% reduction in metronidazole bioavailability occurred with 30 mL of an aluminiiim hydroxide/simeticone suspension, and a 21.3% reduction occurred with a single 4-g dose of colestyramine. The clinical importance of these reductions is probably small, and no special precautions seem necessary. 

H. Bundgaard, C. Larsen, E. Arnold, Prodrugs as Drug Delivery Systems XXVII. Chemical Stability and Bioavailability of a Water-Soluble Prodrug of Metronidazole for Parenteral Administration , Int. J. Pharm. 1984, 18, 79-87. 

Oral bioavailability is almost 100%. Metronidazole is protein bound for less than 20% and is widely distributed, including the CNS. It is metabolized in the liver with an elimination half-life of 8 hours. Common adverse effects include nausea, headache and taste disturbances. With alcohol a severe disulfiram-like reaction, with flushing, sweating and abdominal cramps will occur. 

The coadministration of mycophenolate mofetil with antacids results in decreased absorption. The plasma MPA concentration is significantly reduced by cholestyramine due to binding of the cholestyramine to MPAG in the intestine and interfering with the enterohepatic recirculation of the drug. The bioavailability of mycophenolate mofetil is higher when administered with tacrolimus as opposed to cyclosporine. The bioavailability of MPA is reduced by antibiotics including fluoroquinolones and metronidazole. 

Bundgaard, H., C. Larsen, and E. Arnold. 1984a. Prodrugs as drug delivery systems. XXVII. Chemical stability and bioavailability of a water-soluble prodrug of metronidazole for parenteral administrated. 

Sidelmann UG, Cornett C, Tjornelund J, Hansen SH (1996) A comparative study of precision cut liver slices, hepatocytes and liver microsomes from the Wistar rat using metronidazole as a model substance. Xenobiotica 26 709-722 Stratford RE, Clay MP, Heinz BA et al. (1999) Application of Oral Bioavailability Surrogates in the Design of Orally Active Inhibitors of Rhinovirus Replication. J Pharm Sci 88 747-753... 

METRONIDAZOLE MYCOPHENOLATE Likely 1 in plasma concentration of mycophenolate Theoretically, drugs that alter gastrointestinal flora may 1 oral bioavailability of mycophenolic acid products by 1 bacterial hydrolytic enzymes that are responsible for regenerating mycophenolic acid from its glu-curonide metabolites following first-pass metabolism Avoid co-administration... 

Hoffmann, C. Focke, N. Franke, G. Zschiesche, M. Siegmund, W. Int. comparative bioavailability of metronidazole formulations (vagimid) after oral and vaginal administration. J. Clin. Pharm. Ther. 1995, 33, 232-239. 

Rajnarayana K, Reddy MS, Krishna DR. Diosmin pretreatment affects bioavailability of metronidazole. Eur J Chn Pharmacol 2003 58(12) 803-7. 

Metronidazole is rapidly and well absorbed after p.o. administration to horses, with a bioavailability... 

Table 2.2 Oral bioavailability in horses of rifampin (5mg/kg aqueous suspension), metronidazole (20mg/kg aqueous suspension), pyrimethamine (1 mg/kg suspended in corn syrup), trimethoprim (5mg/kg) and sulphadiazine (25mg/kg oral paste combination preparation).

Spenard J, Aumais C, Massicotte J, Tremblay C, Lefebvre M. Influence of omeprazole on bioavailability of bismuth following administration of a triple capsule of bismutii biskalcitrate, metronidazole, and tetracycline. J Clin Pharmacol (2004) 44, 640-5. 

Esomeprazole, lansoprazole and omeprazole do not alter the pharmacokinetics of amoxicillin, and omeprazole does not alter bacampicillin bioavailability. Isolated reports describe glossitis, stomatitis and/or black tongue in a small number of patients when treated with lansoprazole and antibacterials, which included amoxicillin, clarithromycin and metronidazole. 

Ortiz PG, Hansen SH, Shah VP, Menne T, Benfeldt E. The effect of irritant dermatitis on cutaneous bioavailability of a metronidazole formulation, investigated by microdialysis and dermatopharmacokinetic method. Contact Dermatitis. 2008 59 23-30. 

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