Antimicrobial agents combinations

Mag nesia. ndAlumina. Suspension. A mixture of salts, available as Maalox, Mylanta, Gelusil, and Aludrox, contains magnesium hydroxide [1309-42-8] Mg(OH)2, and variable amounts of aluminum oxide in the form of aluminum hydroxide and hydrated aluminum oxide, ie, 2.9—4.2% magnesium hydroxide and 2.0—2.4% aluminum oxide, Al O, for a mixture of 4.9—6.6% combined magnesium hydroxide and aluminum oxide. This mixture may contain a flavoring and antimicrobial agents in a total amount not to exceed 0.5% (see Aluminum compounds, aluminum oxide). 

An antimicrobial agent that reduces dental plaque and can be deUvered effectively from toothpaste is a combination of Triclosan [3380-34-5] (0.2% in the toothpaste) and zinc citrate (0.5%) (7). This agent influenced plaque accumulation and reduced the incidence of gingival bleeding in clinical tests. Additional dentifrices for improved gingival health are in the offing. 

Very occasionally a combination of antimicrobial agents exhibits synergy. Synergy is measured against a single microorganism and is exhibited when a combination of two compounds exerts a greater inhibitory effect than could be expected from a simple additive effect of the two compounds in the mixture. 

Antimicrobial additives can be used in polymeric materials to prevent or reduce the growth of bacteria and other organisms. A common antimicrobial agent is 2,4,4 -trichloro-2 -hydroxydiphenyl ether also known as triclosan. Its presence can be detected using combined GC/MS (Figures 8 and 9). 

Table 5. Parenterally administered antimicrobial agents which can be used alone or combined to provide effective coverage of the mixed aerobic-anaerobic infections arising from human colonic bacteria for patients requiring preventive therapy...

The IM and SC routes are by far the most frequently used extravascular parenteral routes of drug administration in farm animals. The less frequently used parenteral routes have limited application, in that they aim at directly placing high concentrations of antimicrobial agent close to the site of infection. These routes of administration include intra-articular or subconjuctival injection and intra-mammary or intra-uterine infusion. These local routes differ from the major parenteral routes in that absorption into the systemic circulation is not a prerequisite for delivery of drug to the site of action. The combined use of systemic and local delivery of drug to the site of infection represents the optimum approach to... 

Rifampicin, a semisynthetic derivative of the antimicrobial agent rifamycin B obtained from Strep-tomyces mediterranei, is bactericidal for intra- and extracellular bacteria. Bacterial RNA synthesis is inhibited by binding to the beta-subunit of DNA-dependent RNA polymerase. Human polymerases are not affected. It has activity against gram-positive and gram-negative cocci, chlamydia as well as mycobacteria. It is used in combination with dapsone for leprosy. 

Because of development of resistance and availability of more advanced antimicrobial agents, the use of sulfonamides is limited. However they are used in combination with trimethoprim. The important therapeutic uses are ... 

Most infections should be treated with a single antimicrobial agent. Although indications for combination therapy exist, antimicrobial combinations are often overused in clinical practice. The unnecessary use of antimicrobial combinations increases toxicity and costs and may occasionally result in reduced efficacy due to antagonism of one drug by another. Antimicrobial combinations should be selected for one or more of the following reasons ... 

Giacometti, A., Cirioni, O., Barchiesi, F., Fortuna, M., and Scalise, G. (1999) In-vitro activity of cationic peptides alone and in combination with clinically used antimicrobial agents against Pseudomonas aeruginosa. J. Antimicrob. Chemother. 44, 641-645. 

Fyfe, L., Armstrong, F. and Stewart, J. (1998) Inhibition of Listeria monocytogenes and Salmonella enteriditis by combinations of plant oils and derivatives of benzoic acid the development of synergistic antimicrobial combinations. International journal of Antimicrobial Agents 9(3), 1 95-1 99. 

Certain combinations of antibiotics,such as (3-lactams and aminoglycosides, show synergism, that is, the combination is more effective than either of the drugs used separately. Because such synergism among antimicrobial agents is rare, they should only be used in special situations summarized in Figure 28.7)... 

Drug therapy, particularly with broad spectrum antimicrobials or combinations of agents, can lead to alterations of the normal microbial flora of the upper respiratory, intestinal and genitourinary tracts, permitting the overgrowth of opportunistic organisms, especially fungi or resistant bacteria. These infections are often difficult to treat. 

Drug Discovery Today 7 25-27 Li AP (2004) In vitro approaches to evaluate ADMET drug properties. Curr Top Med Chem 4 701-706 Li W, Escarpe PA, Eisenberg EJ et al. (1998) Identification of GS 4104 as an orally bioavailable prodrug of the influenza virus neuraminidase inhibitor GS 4071. Antimicrobial Agents and Chemotherapy 42 647-653 Los LE, Welsh DA, Herold EG et al. (1996) Gender differences in toxicokinetics, liver metabolism, and plasma esterase activity observations from a chronic (27-week) toxicity study of enalapril/diltiazem combinations in rats. Drug Metab Dispos 24 28-33... 

Mayers D, Jemesk J, Eyster E, et al. In A double-blind, placebo-controlled study to assess the safety, tolerability and antiretroviral activity of efavirenz (EFV DMP 266) in combination with open-label zidovudine (ZDV) and lamivudine (3TC) in HIV infected patients (DMP 266-004)38th Interscience Conference on Antimicrobial Agents and Chemotherapy (San Diego). Washington DC American Society for Microbiology, 1998 22340. 

The combination of EC and antistatic finishes, achieved with selected products is important for synthetic microfibre textiles. Other common finish combinations include hand builders, flame retardant and antimicrobial agents, which generate valuable and useful multifunctional finishes. 

There are no drugs specifically approved by the FDA to treat Acanthamoeba, necessitating the compounding of all medications.Antimicrobial agents are generally used in combination to increase the likelihood of a successful response. Treatment is often prolonged as the mean time to healing is about 100 days. A small number of patients develop Acanthamoeba sclerokeratitis. It is not known whether this severe scleral inflammation is infective or immime mediated. 

Phenylephrine and the imidazole derivatives are chemically compatible with a variety of compounds. They can be combined in ophthalmic formulations with antihistamines, corticosteroids, and antimicrobial agents. 

Treatment of microbial keratitis is started immediately irrespective of whether microbiologic evaluation has been performed. The best antimicrobial agent or agents to use initially is debated in the ophthalmic literature. The two main choices for initial antibiotic treatment are the combination of two fortified antibiotics, such as cefazolin and tobramycin, or monotherapy with topical fluoroquinolones. Just as with the decision to culture, the choice of antibiotic is often influenced by history and clinical presentation. Milder presentations, in low-risk... 

Most clinicians use a combination of oral antimicrobial agents and corticosteroids until there are definite signs of disease resolution. Decreasing inflammation with healing... 

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