Metronidazole antimicrobial effects

Antimicrobial agents, particularly metronidazole, are frequently used in attempts to control Crohn s disease but are not useful in ulcerative colitis. Metronidazole is of value in some patients with active Crohn s disease, particularly involving the perineal area or fistulas. The mechanism of metronidazole s effect on Crohn s disease has not been determined but is theorized to relate to interruption of a bacterial role in the inflammatory process. Ciprofloxacin has also been used for treatment of IBD. 

ANTIPARASITIC AND ANTIMICROBIAL EFFECTS Metronidazole and related nitroimidazoles are active in vitro against a wide variety of anaerobic protozoal parasites and anaerobic bacteria. The drug also has potent amebicidal activity against E. histolytica. 

Controlled and sustained drug delivery has recently begun to make an impression in the area of treatment of dental diseases. Many researchers have demonstrated that controlled delivery of antimicrobial agents, such as chlorhexidine [128-130], ofloxacin [131-133], and metronidazole [134], can effectively treat and prevent periodontitis. The incidence of dental caries and formation of plaque can also be reduced by controlled delivery of fluoride [135,136]. Delivery systems used are film-forming solutions [129,130], polymeric inserts [132], implants, and patches. Since dental disease is usually chronic, sustained release of therapeutic agents in the oral cavity would obviously be desirable. 

Animal and human studies support the use of antibiotics for the prevention of infectious morbidity and mortality in severe ANP. The most effective antimicrobial agents are the fluoroquinolones, imipenem-cilastatin, and metronidazole, which achieve adequate penetration into pancreatic juice and necrotic tissue and inhibit the growth of enteric bacteria. Although a recent meta-analysis [185] suggested that prophylactic antibiotic administration reduces sepsis and mortality and this approach has been recommended by recent guidelines and consensus state-... 

Metronidazole and tinidazole are the only antimicrobial agents available in the United States that are consistently effective in T. vaginalis infections. 

Echinacea (Echinacea purpurea) Uses immune system stimulant prevention/Rx of colds, flu as supportive th apy for colds chronic infxns of the resp tract lower urinary tract Action Stimulates phagocytosis cytokine production T resp cellular activity topically exerts anesthetic, antimicrobial, anti-inflammatory effects Efficacy Not established may X severity duration of URI Available forms Caps w/ powdered herb equivalent to 300-500 mg, PO, tid pressed juice 6-9 mL, PO, once/d tine 2-4 mL, PO, tid (1 5 dilution) tea 2 tsp (4 g) of powdered herb in 1 cup of boiling water Noles/SE Fever, taste p -version, urticaria, angioedema Contra w/ autoimmune Dz, collagen Dz, progressive systemic Dz (TB, MS, collagen-vascular disorders), HIV, leukemia, may interfere w/ immunosuppressive therapy Interactions t Risk of disulfiram-like reaction W/ disulfiram, metronidazole T risk of exacerbation of HIV or AIDS W/ chinacea amprenavir, other protease inhibitors X effects OF azathioprine, basiliximab, corticosteroids, cyclosporine, daclizumab, econazole vag cream, muromonab-CD3, mycophenolate, prednisone, tacrolimus EMS Possible immunosuppression... 

Jensen J., P.H. Krogh, and L.E. Sverdmp (2003). Effects of the antimicrobial agents tiamuhn, olanquindox and metronidazole and the anthelmintic ivermectin on the soil invertebrate species Folsomia fimetaria (Collembola) and Enchytraeus crypticus (Ench3draeidae). Chemosphere 50 437-443. 

Many antimicrobial agents have similar pharmacokinetic properties when given orally or parenterally (ie, tetracyclines, trimethoprim-sulfamethoxazole, quinolones, chloramphenicol, metronidazole, clindamycin, rifampin, linezolid and fluconazole). In most cases, oral therapy with these drugs is equally effective, is less costly, and results in fewer complications than parenteral therapy. 

In a study of analogues of the antibiotic metronidazole (12.a, R = OH), antimicrobial activity against T. vaginalis (log AA) was correlated to activation free energy of electroreduction (AG) and lipophilicity (log P). Both AG and log P are whole molecule parameters. Create a Hansch equation based on these parameter values and following activity data. Interpret the effect of each parameter on antimicrobial activity. (Chien, Y. W., Mizuba, S. S. Activity-Electroreduction Relationship of Antimicrobial Metronidazole Analogues. J. Med. Chem. 1978, 21, 374—380.)... 

In most instances patients demonstrate significant improvement of clinical symptomatology and physical signs in the first 2 to 3 weeks. Many patients, however, require chronic therapy and demonstrate exacerbations of the disease during its course. Metronidazole (MetroGel) is a topical gel developed to treat the skin of the facial area in patients with chronic disease and thus reduce the reliance on oral antimicrobial agents. It is applied twice daily. Although not yet an approved use, metronidazole gel applied to the eyelids was found to be an effective treatment of ocular rosacea. 

Antimicrobials. Aztreonam, cefamandole, chloramphenicol, ciprofloxacin, co-trimoxazole, erythromycin, fluconazole, itraconazole, ketoconazole, metronidazole, miconazole, ofloxacin and sulphonamides (including co-trimoxazole) increase anticoagulant effect by mechanisms that include interference with warfarin or vitamin K metabolism. Rifampicin and griseofulvin accelerate warfarin metabolism (enzyme induction) and reduce its effect. Intensive broad-spectrum antimicrobials, e.g. eradication regimens for Helicobacter pylori (see p. 630), may increase sensitivity to warfarin by reducing the intestinal flora that produce vitamin K. 

In contrast to ulcerative colitis, about 50% of patients with Crohn s colitis will respond to metronidazole given for up to 3 months, although adverse effects including alcohol intolerance, and peripheral neuropathy from such prolonged therapy often limit its use. The drug is also helpful in controlling perianal and small bowel disease and it decreases the incidence of anastamotic recurrence after surgery. Other antimicrobials, particularly ciprofloxacin may also be effective. 

Antimicrobial agents most likely to be affected by the first-pass effect include trimethoprim, sulphonamides, fluoroquinolones, chloramphenicol, metronidazole and rifampin. The metabolites of trimethoprim, sulphonamides, most fluoroquinolones and chloramphenicol are inactive, while ciprofloxacin and sarafloxacin formed by N-dealkylation of enrofloxacin and difloxacin, respectively, and desacetylrifampin have antimicrobial activity similar to or greater than (ciprofloxacin) the parent drug. Certain antimicrobial agents (chloramphenicol and erythromycin) inhibit hepatic microsomal enzyme activity, whereas rifampin is a potent inducer of hepatic microsomal enzymes. 

An important determinant of successful HP eradication therapy is the presence of preexisting antimicrobial resistance. " " Metronidazole resistance is most common (10% to 60%), but varies depending on prior antibiotic exposure and geographic region. 37,38,49 The clinical importance of metronidazole resistance in eradicating HP remains uncertain, as the synergistic effect of combining metronidazole with other antibiotics appears to render resistance to metronidazole less important. Ehimary resistance to clarithromycin is lower (10% to 15%) than with metronidazole, but it is more likely to affect... 

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