Sulfamethoxazole, consider

Fludarabine Consider prophylactic use of trimethoprin-sulfamethoxazole Fludarabine 25 mg/M2 IV days 1-5... 

The answer is d. (Hardman, p 989.) Both trimethoprim-sulfamethoxazole and pentamidine are effective in pneumonia caused by E carinii. This protozoal disease usually occurs in immunodeficient patients, such as those with AIDS. Nifurtimox is effective in trypanosomiasis and metronidazole in amebiasis and leishmaniasis, as well as in anaerobic bacterial infections. Penicillins are not considered drugs of choice for this particular disease state. 

Initial therapy with trimethoprim-sulfamethoxazole appears to be effective for CA-MRSA and should be considered in geographic areas in which CA-MRSA are commonly encountered. Alternative agents for documented infections with resistant gram-positive bacteria such as methicil-lin-resistant staphylococci and vancomycin-resistant enterococci include linezolid, quinupristin/dalfopristin, daptomycin, and tigecycline. 

Tetracycline or trimethoprim-sulfamethoxazole and fluoroquinolones are recommended as alternatives for infections caused by P. multocida or those allergic to penicillins (but not in children or pregnant women). Erythromycin may be considered an alternative in growing children or pregnant women. 

The recommended treatment is doxycycline (200 mg/day) plus rifampin (600 mg/day) for six weeks. An alternative effective treatment is six weeks of doxycycline (200 mg/day) plus streptomycin (1 gm/day) for three weeks. Trimethoprim-sulfamethoxazole given four to six weeks is less effective. In 5 to f 0 percent of cases, there may be a relapse or treatment failure. Regarding prophylaxis, killed and live attenuated human vaccines are available in many countries but are considered of unproven efficacy. There tends to be no information on the use of antibiotics for prophylaxis against human brucellosis. 

Tetracycline 500 mg every six hours or doxycycline 100 mg every twelve hours for five to seven days will shorten the duration of illness, and fever usually disappears within one to two days after treatment is begun. Ciprofloxacin and other quinolones are active in vitro and should be considered for victims unable to take tetracycline or doxycycline. Successful treatment of Q fever endocarditis is much more difficult. Tetracycline or doxycycline given in combination with trimethoprim-sulfamethoxazole (TMP-SMX) or rifampin for twelve months or longer has been successful in some cases. However, valve replacement is often required to achieve a cure. 

Trimethoprim exhibits broad-spectrum activity. It is most commonly used in combination with sulfamethoxazole and is active against most gram-positive and gramnegative organisms, especially the Enterobacteriaceae. There is little activity against anaerobic bacteria P. aeruginosa, enterococci, and methiciUin-resistant staphylococci should be considered resistant to trimethoprim. 

A combination of trimethoprim-sulfamethoxazole is effective treatment for a wide variety of infections including P jiroveci pneumonia, shigellosis, systemic salmonella infections, urinary tract infections, prostatitis, and some nontuberculous mycobacterial infections. It is active against most Staphylococcus aureus strains, both methicillin-susceptible and methicillin-resistant, and against respiratory tract pathogens such as the pneumococcus, Haemophilus sp, Moraxella catarrhalis, and Klebsiella pneumoniae (but not Mycoplasma pneumoniae). However, the increasing prevalence of strains of E coli (up to 30% or more) and pneumococci that are resistant to trimethoprim-sulfamethoxazole must be considered before using this combination for empirical therapy of upper urinary tract infections or pneumonia. 

It is important to consider the influence of interaction between functional groups of drugs that leads to their habit modification when formulated in suspension dosage form. Proton transfer from the N atom of sulfamethoxazole to the pyrimidine basic N1 atom of trimethoprim has been reported to occur in their equimolar complexes. Bettinetti et al. have reported nucleation of the complex of trimethoprim and sulfa-methoxypyridazine (1 1) to be accelerated by water or wet granulation. Our studies on cotrimoxazole (unpublished results) revealed immediate formation of fine needle-shaped crystals irrespective of the initial shape of sulfamethoxazole and trimethoprim crystals as a result of the interaction between the two drugs in suspension form. Small needles (Fig. 6A) were... 

Most patients presenting with pyuria will, in facL have infection that requires treatment. Single-dose or short-course therapy with trimethoprim-sulfamethoxazole has been used effectively, and prolonged courses of therapy are not necessary for most patients. If single-dose or short-course therapy is ineffective, a culture should be obtained. If the patient reports recent sexual activity, therapy for C. trachomatis should be considered. Chlamydial treatment should consist of 1-g azithromycin or doxycycline 100 mg twice daily for 7 days. Often, concomitant treatment of all sexnal partners is re-qnired to cure chlamydial infections and prevent reacqnisition (see Chap. 115). 

Several possibilities come to mind. One is that the sulfonamide actually forms a pteridinyl derivative such as I, which in turn may tend to reduce the availability of the pteridyl pyrophosphate ester D, and decrease the production of G. A condensation product of sulfamethoxazole and the pteridyl alcohol B was actually obtained, raising the possibility of a sulfonamide-containing imposter of dihydropteroic acid arising. A second viable possibility is to consider a tautometric equilibrium between the pteridine alcohol B and the aldehyde form C, which will very likely form the Schiff base derivative J, with the p-amino function of a sulfonamide. This would also lead to a pteridyl alcohol depletion from the path of the FH2 synthesis (Seydel, 1968). 

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