Genotyping patients

The current standard of treatment for chronic HCV infection is a combination of once-weekly PEG-IFN and a daily oral dose of ribavirin. Sustained virologic response rates are 54% to 56%. Therapy is optimized based on genotype, patient weight, and response to therapy. Recommended treatment regimens for HCV infection are given in Table 25-8 and Fig. 25-3. 

The nature of the test to be used to genotype patients in the trial and subsequently in general use is also critical. 

The hypothesis that the optimal dose of SSRI may be dependent on HTT variants is intriguing it can be speculated that dose-response correlations differ across genotypes patients with one or two copies of the short variant of the serotonin transporter might respond at lower doses and/or plasma levels of SSRIs than patients with two copies of the long variant. This hypothesis could be tested using flexible-dose placebo-controlled designs coupled with family-based association studies. 

The study population consisted of CYP2C19-genotyped patients infected with H. pylori who had completed initial treatment with omeprazole 20 mg or lansoprazole 30 mg twice daily, and clarithromycin 200 mg and amoxicillin 500 mg three times a day for 1 week. Patients in whom the infection was not eradicated after initial treatment were retreated with lansoprazole 30 mg and amoxicillin 500 mg four times a day for 2 weeks. 

Figure 24.4 Illustration of value of genotyping patients. See text for explanation.

Bondolfi G, Morel F, Crettol S, Rachid F, Baumann P, Eap CB. Increased clozapine pla a concentrations and side effects induced by smoking cessation in 2 CYP1A2 genotyped patients. TherDrugMonit (2005) 27, 539-43. 

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