Tetracyclines combination therapy

Erythromycin has efficacy similar to tetracycline, but it induces higher rates of bacterial resistance. Resistance may be reduced by combination therapy with benzoyl peroxide. Erythromycin can be used for patients who require systemic antibiotics but cannot tolerate tetracyclines, or those who acquire bacterial resistance to tetracyclines. The usual dose is 1 g/day with meals to minimize GI intolerance. 

Treatment of H. pylori infection typically consists of a combination therapy, using several drugs simultaneously.42 For example, one common form of triple therapy consists of two antibacterials (amoxicillin and clarithromycin) and one of the PPIs described earlier in this chapter.17 36 Alternatively, various quadruple therapies have been used combining bismuth compound (described later in the section on Treatment of Diarrhea ) with a PPI and two antibacterials (e.g., tetracycline and metronidazole).5,36 These drug regimens are typically administered for 1 to 2 weeks and... 

Amebiasis. The causative agent, Entamoeba histolytica, lives and multiplies in the colon (symptom diarrhea), its cyst form residing also in the liver among other sites. In tropical regions, up to half the population can be infested, transmission occurring by the fe-cal-oral route. The most effective treatment against both intestinal infestation and systemic disease is administration of metronidazole. If monotherapy fails, combination therapy with chloroquine, emetine or tetracyclines may be indicated. 

TETRACYCLINE ANTIMALARIALS -ATOVAQUONE 1 atovaquone levels (40%) Uncertain Not clinically significant combination therapy has been used effectively... 

When chronic Q fever infection is manifested by infective endocarditis, treatment is very difficult the mortality is 24% even when patients receive appropriate treatment.73 At least 2 years of therapy are required, usually with a tetracycline combined with rifampin or a quinolone, although tri-methoprim-sulfamethoxazole has also been used.84 Quinolones alone or in combination have also been effective. Most recently, the addition of hydroxychloroquine to tetracycline has shown promising results both in vitro87 and in a small number of patients.88... 

Another subclass of proteases attacks internal peptide bonds and Hberates large peptide fragments. Bromelain, a plant protease derived from the stem of the pineapple plant, can even produce detectable semm proteolysis after oral adrninistration (180). Oral therapy with bromelain significantly reduces bmising that stems from obstetrical manipulations (181). Bromelain—pancreatin combinations have been more effective in digestive insufficiency compared to either pancreatin or placebo (182,183). Bromelain may also enhance the activity of antibiotics, especially tetracycline, when adrninistered concurrently (184). 

Helidac therapy combines bismuth subsalicylate, metronidazole, and tetracycline in a consumer-tested, patient-friendly kit. 

Antibiotics also are active against other protozoans. Tetracycline and erythromycin are alternative therapies for the treatment of intestinal amebiasis. Clindamycin, in combination with other agents, is effective therapy for toxoplasmosis, pneumocystosis, and babesiosis. Spiramycin is a macrolide antibiotic that is used to treat primary toxoplasmosis acquired during pregnancy. Treatment lowers the risk of the development of congenital toxoplasmosis. 

When acne is severe it may require medidnes that have to be taken by mouth and these may be stronger antibiotics combined with hormone therapy. Tetracyclines and erythromycin are typically used and they have to be taken for many weeks, but there are signs that bacteria are becoming resistant to these antibiotics and if there is no improvement in the acne within three months then this type of treatment has to be discontinued, or a much stronger antibiotic tried. Hormone therapy is available for young women with severe acne and this can block the sebum-stimulating effect of natural hormones - as well as having a contraceptive effect. 

Infections limited to soft tissue will require between 7 and 10 days of intravenous therapy followed by an additional 14 days of oral therapy (total duration 2-4 weeks). If MRSA is isolated, intravenous vancomycin must not be switched to oral vancomycin which has negligible absorption from the gastrointestinal tract. Oral agents may be selected from rifampicin, tetracyclines, fusidic acid or trimethoprim depending on sensitivity data and a combination of two agents is recommended. Oral linezolid monotherapy is an effective alternative. 

Tetracyclines and Metals. Tetracyclines can combine with metal ions, such as calcium, magnesium, aluminum, and iron, in the GI tract to form complexes that are poorly absorbed. Thus, the simultaneous administration of certain drugs (e.g., antacids, iron preparations, products containing calcium salts) by patients on tetracycline therapy could result in a significant decrease in the amount of antibiotic absorbed. When two drugs are recognized as having a potential to interact, there is sometimes a tendency to believe that one of them should be discontinued. In the case of the tetracycline antacid interactions, problems can be... 

Amlnocyclitols in general, and spectinomycin in particular, are effective in no more than half the patients with NGU, an observation that correlates with the fact that U. urealyticum is susceptible but C. trachomatis is not. Conversely, sulfonamide therapy is successful in chlamydial NGU, but not in NGU associated with U. urealyticum. The differential response to sulfisoxazole or spectinomycin has been used to differentiate chlamydial from ureaplasmal NGU, and a combination of these two agents deserves a clincial trial as an alternative to the tetracyclines. C. trachomatis and U. urealyticum are individually susceptible to several other antimicrobial agents,but all are clinically ineffective or have not been subjected to controlled studies. 

It is fascinating to note the recent re-awakening of interest in bismuth therapies since the discovery in 1982 that the intestinal bacterium Helicobacter pylori may well initiate ulcer formation by excreting acid. Bismuth, in common with many heavy metals, is bactericidal and so the lasting effects of bismuth citrate therapy may well be a combination of ulcer healing (from the precipitates) as well as ulceration initiator suppression (from the bacteriocidal action). In vitro the organism is sensitive to bismuth but results in vivo are feeble. However, combinations of bismuth with antibiotics such as amoxicillin or tetracycline have success rates of 80%, i.e. four times the 20% success rate described above. 

Adverse effects of tetracyclines include resistant bacteria, folliculitis, candidiasis, gastrointestinal upset, and phototoxic effects. Tetracyclines must not be combined with systemic retinoids because of the increased probability for development of intracranial hypertension. Tetracycline is used in the treatment of moderate to severe acne vulgaris. It is the least expensive of the tetracyclines and therefore often prescribed for initial therapy. A common initial approach includes tetracycline 1 g daily (500 mg twice daily), 1 hour before meals after 1 or 2 months, when marked improvement of inflammatory lesions is observed, the dose may be decreased to 500 mg every day, for another 1 or 2 months. Drawbacks to the use of tetracycline include also a drug-food interaction with dairy prodncts. 

For infected bite wounds, penicillin and a peniciUinase-resistant penicillin or amoxiciUin-clavulanic acid 875 mg/125 mg oraUy twice daily (40 mg/kg per day oraUy of the amoxicillin component divided into two doses) should be started empirically pending the culture results. Tetracyclines or a combination of clindamycin plus a fluoroquinolone or trimethoprim-sulfamethoxazole may be used as an alternative therapy for the penicillin-allergic patient. Hospitalization for minor wounds is not necessary if surgical repair of vital structures has not been performed. Patients suffering serious injuries or clenched-fist injuries should be started on intravenous antibiotics. Duration of therapy for infected bite injuries should be 7 to 14 days. 

Resistant strains of P. acnes are emerging that may respond to jndicions nse of retinoids in combination with antibiotics. Commonly nsed topical antimicrobials in acne inclnde erythromycin, clindamycin (Cleocin-t), and benzoyl peroxide and antibiotic-benzoyl peroxide combinations (Benzamycin, Benzaclin, others). Other antimiaobials nsed in treating acne inclnde sulfacetamide (Klaron), sulfacetamide/sulfur combinations (Snlfacet-R), metronidawie (Metrocream, Metro-Gel, noritate), and azelaic acid (Azelex). Systemic therapy is prescribed for patients with more extensive disease and acne that is resistant to topical therapy. Effective agents inclnde tetracycline (snmycin, others), minocycline (MINO-CIN, others), erythromycin (ERYC, others), clindamycin (CLEOCIN), and trimethoprim-sulfamethoxazole (bactrim, others). Antibiotics nsnally are administered twice daily, and doses are tapered after control is achieved. 

H. pylori [269]. Multiple studies investigating azithromycin in combination with one or two other drugs (amoxicillin, metronidazole, tinidazole, tetracycline, bismuth subsalicylate, and/or a PPl) revealed that the more effective azithromycin-containing regimens involved triple therapy [270-275]. In contrast to clarithromycin, azithromycin is not FDA approved for treatment of H. pylori disease. The role of azithromycin in the treatment of H. pylori remains to be defined. Several in vitro and animal studies have suggested that azithromycin may be clinically active in the treatment of early Lyme disease (LD) [276-278], Several clinical trials of treatment of early Lyme disease performed in the United States and Europe comparing azithromycin vs. doxycycline, oral penicillin, amoxicilUn/ probenicid, or oral amoxicillin revealed no significant difference in clinical outcome [279-283]. The precise role and dose of azithromycin in the treatment of early LD remains to be established. 

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