++
The agents discussed in this chapter include miscellaneous antimicrobials,
including those specific for urinary infections, and disinfectants
and antiseptics (Figure 30–1). Because physical therapists
often treat patients with infections and use equipment that can
potentially transfer pathogens, the use of antiseptics and disinfectants
discussed in the latter half of the chapter is particularly relevant
to rehabilitation practice.
++
++
Chemistry and
Pharmacokinetics
++
Metronidazole is a nitroimidazole drug used primarily in treating
infections caused by anaerobic bacteria and protozoa. Metronidazole
can be administered orally, intravenously, or by rectal suppository.
The drug penetrates readily into almost all tissues, including the
cerebrospinal fluid, achieving levels similar to plasma.
++
Mechanism of
Action and Clinical Uses
++
Metronidazole kills amoebae, bacteria, and sensitive protozoans.
The drug is readily taken up by anaerobic organisms and cells, where
it acts by disrupting DNA and inhibiting nucleic acid synthesis.
Metronidazole is the treatment of choice for anaerobic or mixed
intra-abdominal infections, pseudomembranous colitis, and brain
abscess involving susceptible organisms. Metronidazole may be used
in treating anaerobic infections such as might be present in empyema,
lung abscess, bone and joint infections, and diabetic foot ulcers.
In the treatment of diabetic lower extremity infections in older
males, once-daily use of metronidazole combined with another antibiotic
has been shown to be as effective as the traditional antibiotic
regimen given every 6 hours with significantly less associated cost.
Metronidazole is also used to treat infections caused by Clostridium difficile, a gram-positive
bacillus that can precipitate pseudomembranous colitis, which is
clinically manifested as severe diarrhea (C
difficile–associated diarrhea, CDAD). C difficile is one of the most rapidly
increasing communicable infections, possibly exceeding methicillin-resistant Staphylococcusaureus (MRSA)
and other drug-resistant microorganisms.
++
Metronidazole has many other uses. As an oral tablet or topical
vaginal gel, it effectively treats bacterial vaginosis. As part
of a multidrug regimen, metronidazole is commonly used in the eradication
of Helicobacter pylori in peptic
ulcer disease. As an antiprotozoaldrug, metronidazole is the drug
of choice for treating giardiasis (traveler’s diarrhea)
and the common sexually transmitted disease trichomoniasis. Metronidazole
is also used as a topical antibiotic for the chronic dermatologic
condition rosacea.
++
The most common adverse effects include nausea or vomiting, gastrointestinal
discomfort, diarrhea, headache, dizziness, dry mouth, and altered
taste sensation (especially the perception of a sharp metallic taste).
Because metronidazole has a disulfiram-like effect, drinking alcoholic
beverages while taking metronidazole can cause stomach pain, nausea,
vomiting, headache, and flushing of the face. Patients should be
instructed to avoid alcohol (including alcohol-containing cough
syrups) while taking this drug and for at ...