Trimethoprim-sulfamethoxazole dosage

The most common adverse effects of lamivudine seen at doses used to treat HBV are mild they include headache, malaise, fatigue, fever, insomnia, diarrhea, and upper respiratory infections. Elevated alanine aminotransferase (ALT), serum lipase, and creatine kinase may also occur. The safety and efficacy of lamivudine in patients with decompensated liver disease have not been established. Dosage adjustment is required in individuals with renal impairment. Coadministration of trimethoprim-sulfamethoxazole decreases the renal clearance of lamivudine. 

Zidovudine should be used cautiously with any other agent that causes bone marrow suppression, such as interferon-a, trimethoprim-sulfamethoxazole, dap-sone, foscarnet, flucytosine, ganciclovir, and valganci-clovir. Probenecid and interferon-p inhibit the elimination of zidovudine therefore, a dosage reduction of zidovudine is necessary when the drugs are administered concurrently. Ribavirin inhibits the phosphorylation reactions that activate zidovudine, and zidovudine similarly inhibits the activation of stavudine thus, the coadministration of zidovudine with ribavirin or stavudine is contraindicated. 

Pentamidine is a well-established alternative therapy for pulmonary and extrapulmonary disease caused by P jiroveci. The drug has somewhat lower efficacy and greater toxicity than trimethoprim-sulfamethoxazole. The standard dosage is 3 mg/kg/d intravenously for 21 days. Significant adverse reactions are common, and with multiple regimens now available to treat P jiroveci infection, pentamidine is best reserved for patients with severe disease who cannot tolerate or fail other drugs. 

Cotrimoxazole (trimethoprim-sulfamethoxazole) or trimethoprim alone may be nsed for treating patients who do not tolerate tetracycline and erythromycin or in cases of resistance to these antibiotics. The adnlt dosage is usually 800 mg sulfamethoxazole and 160 mg trimethoprim twice daily. 

Alert All dosage forms have same 5 1 ratio of sulfamethoxazole (SMX) to trimethoprim (TMP). 

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... 

Bonazzi, D. Andrisano, V. Di Pietra, A.M. Cavrini, V. Anal3rsis of trimethoprim-sulfonamide drug combinations in dosage forms by UV spectroscopy and liquid chromatography (HPLC). Farmaco, 1994, 49, 381-386 [simultaneous sulfadiazine, sulfamethoxazole, sulfamethoxypyridazine]... 

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