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Tetracycline interaction with other drugs

Reduced absorption due to complex formation or other interactions between drugs and intestinal components leading to poor absorption has been described in a few cases. One example is the precipitation of cationic drugs as very poorly-soluble salts with bile acids, which has been reported for several compounds [62], Another well-known example is the complex formation between tetracycline together with calcium due to chelation after administration of the drug together... [Pg.513]

Chemical drug interactions result when two administered substances combine with each other chemically Tetracyclines complex with Ca (in milk), with aluminum (Al) and magnesium (Mg) (often components of antacids), and with Fe (in some multiple vitamins) to reduce the absorption of the tetracycline antibiotic. [Pg.52]

Drugs may bind to other drugs in the gut. We have already met the iron/calcium interaction with tetracyclines, which reduces the absorption of the antibiotic. [Pg.151]

The absorption of tetracyclines is markedly reduced by aluminium and magnesium containing antacids. Tetracyclines may chelate other ions, in particular iron salts, with resultant poor absorption of both drugs. This interaction can be avoided by giving iron salts either 3 hours before or 2 hours after the tetracycline. [Pg.250]

Buffering agents that are compounded with didanosine to counteract its degradation by gastric acid may interfere with the absorption of other drugs that require acidity (e.g., indinavir, delavirdine, ketoconazole, fluoroquinolones, tetracyclines, dapsone). An enteric-coated formulation Videx EC) that dissolves in the basic pH of the small intestine is not susceptible to these interactions. Ganciclovir and valganciclovir can increase blood levels of didanosine. The use of zalcitabine with didanosine is not recommended because that combination carries an additive risk of peripheral neuropathy. The combination of didanosine with stavudine increases the risk of pancreatitis, hepatotoxicity, and peripheral neuropa-... [Pg.587]

Apart from being a diffusional barrier, mucin can also interact with drugs to decrease their bioavailability, as has been shown with tetracycline [106], phenylbutazone, and warfarin [107]. On the other hand, studies in rats showed that binding of some water-soluble drugs to intestinal mucus was essential for their absorption and that damage to the mucus significantly reduced absorption [108], The acidic mucus is essential for lipid absorption and could be important for the diffusion of lipophilic drugs (see below). [Pg.15]

Several other examples of drug-membrane interactions have been reported. Using X-ray diffraction techniques, interactions with tetracyclines [75], pindolol [76], and chlorpromazine [77, 78] have been described. In these studies, it was shown that in the presence of chlorpromazine the bilayer thickness or lipid head group separation in DPPC liposomes is only 30 A, which is about 20 A smaller than two fully extended DPPC molecules. Chlorpromazine produced an interdigitated phase, which is in agreement with the observed effect of chlorpromazine on the shape of erythrocytes. [Pg.86]

Chemical interactions in the gastrointestinal tract between nutrients and drugs may considerably reduce the absorption of some drugs calcium ions from dairy products form insoluble and therefore nonabsorbable complexes with the antibiotic tetracycline. On the other hand, certain drugs are irritants to the gastrointestinal tract (nonsteroidal antiinflammatory drugs and potassium chloride tablets) and must be ingested with food. [Pg.3]

Fig. I.l A drug chelation interaction. Tetracycline forms a less-soluble chelate with iron if the two drugs are allowed to mix within the gut This reduces the absorption and depresses the serum levels and the antibacterial effects (after Neuvonen PJ, BMJ (1970) 4, 532, with permission). The same interaction can occur with other ions such as Al, Ca, Mg, Bi and Zi . ... Fig. I.l A drug chelation interaction. Tetracycline forms a less-soluble chelate with iron if the two drugs are allowed to mix within the gut This reduces the absorption and depresses the serum levels and the antibacterial effects (after Neuvonen PJ, BMJ (1970) 4, 532, with permission). The same interaction can occur with other ions such as Al, Ca, Mg, Bi and Zi . ...
Some of the didanosine preparations (e.g. chewable tablets) are formulated with antacid buffers that are intended to facilitate didanosine absorption by minimising acid-induced hydrolysis in the stomach. These preparations can therefore alter the absorption of other drugs that are affected by antacids (e.g. azole antifungals, quinolone antibacterials, tetracyclines). This interaction may be minimised by separating administration by at least 2 hours. Alternatively, the enteric-coated preparation of didanosine (gastro-resistant capsules) may be used. [Pg.772]

Absorption of antimicrobial agents such as fluoroquinolones and tetracyclines that can be bound by divalent and trivalent cations potentially could be compromised by administration with EN formulas containing these cations. The fluoroquinolones (e.g., levofloxacin and ciprofloxacin) have been best studied in this regard, and results of studies are not consistent. Mechanisms for an interaction between fluoroquinolones and EN formulas other than chelation by cations have been postulated.40 Some institutions hold tube feedings for 30 to 60 minutes or more before and after enteral dosages of fluoroquinolones. Because ciprofloxacin absorption has been shown to be decreased with jejunal administration, this drug probably should not be given by jejunal tube.41... [Pg.1527]

There are problems as well in the absorption of certain drugs in the presence of specific food components. L-Dopa absorption may be inhibited in the presence of certain amino acids formed from the digestion of proteins [43], The absorption of tetracycline is reduced by calcium salts present in dairy foods and by several other cations, including magnesium and aluminum [115-117], which are often present in antacid preparations. In addition, iron and zinc have been shown to reduce tetracycline absorption [118], Figure 17 illustrates several of these interactions. These cations react with tetracycline to form a water-in-soluble and nonabsorbable complex. Obviously, these offending materials should not be co-administered with tetracycline antibiotics. [Pg.62]

Resistance is related largely to changes in cell permeability and a resultant decreased accumulation of drug due to increased efflux from the cell by an energy-dependent mechanism. Other mechanisms, such as production of a protein that alters the interaction of tetracycline with the ribosome and enzymatic inactivation of the drug, have been reported. [Pg.544]

Another point that has defied explanation is this SM is bacteriocidal only during periods of high rates of protein synthesis. Thus other protein inhibitors such as tetracyclines or chloramphenicol should interfere with its action, yet this theoretical drug interaction is not necessarily clinically contraindicated. In fact, a combination of streptomycin and tetracycline is the treatment of choice for glanders and brucellosis. [Pg.252]

The interactions between the oral contraceptives and tetracyclines summarised here are all that have been identified in the literature. Much of the evidence is anecdotal with insufficient controls (if any). These interactions are not adequately established and the whole issue remains controversial. Bearing in mind the extremely wide use of both drugs, any increase in the incidence of contraceptive failure above the accepted failure rate is clearly very low indeed. On the other hand, the personal and ethical consequences of an unwanted pregnancy can be very serious. For this reason, the Faculty of Family Planning and Reproductive Health Care (FFPRHC) Clinical Effectiveness Unit recommends that an additional form of contraception, such as condoms, should be used while taking a short course of antibacterials that do not induce liver eiKymes, and for 7 days after the antibacterial has been stopped. See Hormonal contraceptives + Antibacterials Penicillins , p.981, for more detailed information on how to manage this interaction. [Pg.984]


See other pages where Tetracycline interaction with other drugs is mentioned: [Pg.191]    [Pg.1458]    [Pg.249]    [Pg.16]    [Pg.1587]    [Pg.278]    [Pg.358]    [Pg.915]    [Pg.621]    [Pg.2]    [Pg.113]    [Pg.662]    [Pg.392]    [Pg.25]    [Pg.499]    [Pg.151]    [Pg.169]    [Pg.98]    [Pg.225]    [Pg.3]    [Pg.485]    [Pg.171]   
See also in sourсe #XX -- [ Pg.383 ]

See also in sourсe #XX -- [ Pg.383 ]




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