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Clinical Management Algorithm
Many HCV-infected
patients cannot tolerate full
doses of IFN and ribavirin therapy. It is
recognized that many of the thresholds for dose reduction of IFN or ribavirin
are arbitrary and may vary from center
to center. The important point
is that every practitioner who treats HCV infection should construct an
algorithm with predefined decision points. It is increasingly the goal
to keep as many
patients as possible on full-dose IFN and ribavirin therapy,
even if the patient becomes anemic or thrombocytopenic.
What follows is the ideal (although not always achievable) algorithm for a management strategy directed by the nurse practitioner (Figure 13).
- Assess patients
for symptoms and side effects and perform blood tests at weeks 1, 2,
and 4. Thereafter, perform these assessments at regular intervals every
4 to 8 weeks. If significant anemia occurs (ie, hemoglobin <10 g/dL
or hematocrit <30%), adjust the ribavirin dose downward in 200-mg
increments. If severe anemia occurs (ie, hemoglobin <8.5 g/dL or
hematocrit <26%), discontinue ribavirin and consider intervention
to treat the anemia. We recommend adjunctive therapy with an erythropoietic
growth factor at the physician's discretion. We also recommend weekly
monitoring of blood parameters and blood pressure.
- If side effects
become intolerable or if there are marked decreases in the absolute
neutrophil count (<500 cells/mm3) or platelet counts (<30,000
cells/mm3), adjust the dose of PEG-IFN downward. Again, we
recommend adjunctive therapy with a granulocyte colony-stimulating factor
at the physician's discretion as well as more frequent monitoring of
blood parameters. The clinician must keep in mind that the dose-reduction
recommendations contained in package inserts are overly cautious, and
most clinicians do not adhere to them.
- Following the completion
or discontinuation of therapy, measure aminotransferase levels at 2-,
6-, and 12-month intervals. For responders, repeat the HCV RNA assay
6 months after the end of treatment. Thereafter, the decision whether
or not to continue monitoring should be made on an individual basis.
- For patients with
genotype 1 HCV, repeat the HCV RNA assay at week 12. If HCV RNA levels
have decreased by at least 2 log or have disappeared altogether, continue
therapy for the full 48 weeks while continuing to monitor at 4- to 8-week
intervals. If HCV RNA levels have not decreased by at least 2 log, consider
discontinuation of therapy. This "12-week stopping rule" should
be flexible and open to discussion.
- For patients with
genotype 2 or 3 HCV, assess aminotransferase and HCV RNA levels at the
completion of treatment at 24 weeks, and base further management on
the results of this determination.
- Measure thyroid-stimulating
hormone levels every 3 to 6 months during therapy.
- If a patient becomes pregnant at any time, discontinue treatment immediately. The patient should be counseled regarding the possibility of birth defects and the options available. If the pregnancy is continued to term, the child should be monitored for 2 years both for late-appearing birth defects and for HCV infection. Because of the presence of maternal antibodies, monitoring in the first year should be by HCV RNA PCR.
| MONITORING |
One useful schedule for laboratory tests is illustrated in Table 17.
In addition, all patients
older than 50 years should undergo electrocardiography, and those with
cardiac risk factors should undergo a stress test. Finally, any patient
who develops ophthalmic symptoms should undergo an eye examination. Routine
pretreatment ophthalmic examinations, while suggested in the package insert
for IFNs, seems impractical and not particularly useful to our panel of
experts.
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