https://www.aidsinfo.nih.gov www.hiv-druginteractions.org www.hivinsite.com www.iasusa.org www.hepatitisc.uw.edu/page/treatment/drugs
Combination antiviral therapy against both HIV and hepa-titis B virus (HBV) is indicated in this patient, given the high viral load and low CD4 cell count. However, the use of methadone and possibly excessive alcohol consumption necessitate caution. Tenofovir plus emtricitabine (two nucle-oside/nucleotide reverse transcriptase inhibitors) would be excellent choices as the NRTI “backbone” of a fully sup-pressive regimen, since both are active against HIV-1 and HBV, do not interact with methadone, and are available in a once-daily, fixed-dose combination. A strand inhibitor such as raltegravir or dolutegravir, or the boosted combina-tion of darunavir/ritonavir could be added. There are other alternatives as well. Prior to initiation of this regimen, renal and liver function should be checked, HBV DNA level should be assessed, the patient should be screened for Hepa-titis A and HCV infection, and a bone mineral density test should be considered. Pregnancy should be ruled out, and the patient should be counseled that efavirenz should not be taken during pregnancy. Avoidance of alcohol should be rec-ommended. The potential for lowered methadone levels with darunavir, if used, necessitates close monitoring and possibly an increased dose of methadone. Finally, the patient should be made aware that abrupt cessation of these medications may precipitate an acute flare of hepatitis.
Miscellaneous Antimicrobial Agents; Disinfectants, Antiseptics, & Sterilants
Camille E. Beauduy, PharmD, & Lisa G. Winston, MD*
A 56-year-old man is admitted to the intensive care unit of a hospital for treatment of community-acquired pneumonia. He receives ceftriaxone and azithromycin upon admission, rapidly improves, and is transferred to a semiprivate ward room. On day 7 of his hospitalization, he develops copi-ous diarrhea with eight bowel movements but is otherwise clinically stable. Clostridium difficile infection is confirmed by stool testing. What is an acceptable treatment for the patient’s diarrhea? The patient is transferred to a single-bed room. The housekeeping staff asks what product should be used to clean the patient’s old room.
■ METRONIDAZOLE, FIDAXOMYCIN, RIFAXIMIN, MUPIROCIN, POLYMYXINS, & URINARY ANTISEPTICS
Metronidazole is a nitroimidazole antiprotozoal drug (see Chapter 52) that also has potent antibacterial activity against anaerobes, including Bacteroides and Clostridium species. Metronidazole is selectively absorbed by anaerobic bacteria and sensitive protozoa. Once taken up by anaerobes, it is nonenzymatically reduced by reacting with reduced ferredoxin. This reduction * The authors thank Henry F. Chambers, MD and Daniel H. Deck, PharmD, for their contributions to previous editions of this chapter.
results in products that accumulate in and are toxic to anaerobic cells. The metabolites of metronidazole are taken up into bacterial DNA, forming unstable molecules. This action occurs only when metronidazole is partially reduced, and, because this reduction usually happens only in anaerobic cells, it has relatively little effect on human cells or aerobic bacteria.