Page 918 - Basic _ Clinical Pharmacology ( PDFDrive )

51 Clinical Use of
C H A P T E R

Antimicrobial Agents

Harry W. Lampiris, MD, &
Daniel S. Maddix, PharmD

C ASE STUD Y

A 65-year-old man undergoes cystoscopy because of the 90/50, pulse of 120, temperature of 38.5° C and respira-
presence of microscopic hematuria in order to rule out tory rate of 24. The patient is disoriented but the physical
urologic malignancy. The patient has mild dysuria and exam is otherwise unremarkable. Laboratory test shows
3
pyuria and empirically receives oral therapy with cip- WBC 24,000/mm and elevated serum lactate; urinalysis
rofloxacin for presumed urinary tract infection prior to shows 300 WBC per high power field and 4+ bacteria.
the procedure and tolerates the procedure well. Approxi- What possible organisms are likely to be responsible for
mately 48 hours after the procedure, the patient presents the patient’s symptoms? At this point, what antibiotic(s)
to the emergency department with confusion, dysuria would you choose for initial therapy of this potentially
and chills. Physical exam reveals a blood pressure of life-threatening infection?

The development of antimicrobial drugs represents one of the 3. What are the likely etiologic agents for the patient’s illness?
most important advances in therapeutics, both in the control 4. What measures should be taken to protect individuals exposed
or cure of serious infections and in the prevention and treat- to the index case to prevent secondary cases, and what measures
ment of infectious complications of other therapeutic modalities should be implemented to prevent further exposure?
such as cancer chemotherapy, immunosuppression, and surgery. 5. Is there clinical evidence (eg, from well-executed clinical trials) that
However, evidence is overwhelming that antimicrobial agents antimicrobial therapy will confer clinical benefit for the patient?
are vastly overprescribed in outpatient settings in the USA, and
the availability of antimicrobial agents without prescription in Once a specific cause is identified based on specific microbio-
many developing countries has—by facilitating the development logic tests, the following further questions should be considered:
of resistance—already severely limited therapeutic options in the 1. If a specific microbial pathogen is identified, can a narrower-
treatment of life-threatening infections. Therefore, the clinician spectrum agent be substituted for the initial empiric drug?
should first determine whether antimicrobial therapy is warranted 2. Is one agent or a combination of agents necessary?
for a given patient. The specific questions one should ask include 3. What are the optimal dose, route of administration, and dura-
the following:
tion of therapy?
1. Is an antimicrobial agent indicated on the basis of clinical find- 4. What specific tests (eg, susceptibility testing) should be under-
ings? Or is it prudent to wait until such clinical findings taken to identify patients who will not respond to treatment?
become apparent? 5. What adjunctive measures can be undertaken to eradicate
2. Have appropriate clinical specimens been obtained to establish the infection? For example, is surgery feasible for removal
a microbiologic diagnosis? of devitalized tissue or foreign bodies—or drainage of an

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