The Study of Voriconazole Trough Level in the First Two Weeks After Administration in King Chulalongkorn Memorial Hospital.

Invasive fungal infections are a significant cause of morbidity and mortality in immunocompromised host such as prolong neutropenic patients , post transplantation patients, malignancies or advanced AIDS . The majority of these infections were caused by Aspergillus species, which the first line of treatment is antifungal agent, Voriconazole , a triazole antifungal drug which was approved by the Food and Drug Administration in May 2002 for the treatment of invasive aspergillosis and refractory infections of Scedosporium apiospermum and Fusarium spp. There are two forms of Voriconazole , oral and intravenous form. The recommendation dose is 6 mg/kg twice daily for two dosages, followed by 4 mg/kg twice daily in intravenous form or a loading dose of 400 mg twice daily for two doses is used (for individuals >40 kg), followed by 200 mg twice daily, and in individuals <40 kg the maintenance dose is 100 mg twice daily in oral form.

Voriconazole has a narrow therapeutic window and nonlinear pharmacokinetic profile with wide inter-individual and intra-individual variability, such as age, race, genotypic variation, liver dysfunction, the presence of food and drug-drug interactions with CYP450 inhibitors. These large variations in pharmacokinetics may be associated with decreased efficacy or increased toxicity. Therefore , monitoring of serum trough concentrations is recommended in the following infections: invasive aspergillosis treatment , endophthalmitis; meningitis or osteoarticular infections due to Exserohilum rostratum.

In Thai population , there are different genetic polymorphism from Caucasian ,resulting in a different response to the initial dose and there is limited resources in Thailand , mostly patients are unaccessible for Voriconazole level. Especially,in the period of starting drug, which is the critical period for patients ,most of them are post chemotherapy which may have gastrointestinal problems, mucositis , vomiting or diarrhea ,as well as receiving multiple concurrent medications. All of these affect drug absorption,drug level and efficacy of treatment. Thus, this study was designed to evaluated Voriconazole level in Thai patients in the first two week after administration.

Primary question

• From the first collected of Voriconazole drug level , Are the invasive fungal infection patients in King Chulalongkorn Memorial Hospital achieved the drug level more than 60% ?

Secondary question

• Which factor affecting Voriconazole through level in the first two weeks after administration?

Research Design

• Observational Studies (Descriptive retrospective and prospective study)

Research Methodology

Target Population

• Patients received Voriconazole for treatment or prophylaxis invasive fungal infection

Study population

• Patients in King Chulalongkorn Memorial hospital received Voriconazole for treatment or prophylaxis invasive fungal infection

Sample size

n= ZZ/2P(1-P) /dd

• n = sample size
• P =Incident rate
• From the pilot study of 15 Invasive fungal infection patients in King Chulalongkorn memorial hospital from February to September 2015 , 60% ( 9 of 15 patients) of the first collected of Voriconazole trough level achieved the therapeutic level. replaced P = 0.6
• Z = 95% confident interval = 1.96
• d = acceptable error = 0.10 n = (1.96) (1.96) (0.60)(1-0.60) / (0.10)(0.10) n =92 , sample size = 92

Study processing and data collection

Data collection

• Collected data of patients received Voriconazole in first two weeks of treatment or prophylaxis invasive fungal infection in King Chulalongkorn Memorial hospital in 2015-2017 from outpatient records , inpatient records and computer database in King Chulalongkorn Memorial hospital. This data included
• Baseline characteristics : sex, age ,weight ,BMI ,co-morbid ,personal history of smoking or alcohol drinking
• Basic laboratory investigation : complete blood count , Creatinin , liver function test , albumin level
• Gastrointestinal problems
• Indication of Voriconazole treatment
• Data of invasive fungal infection :
• Data of Voriconazole usage : Loading dose, Maintenance dose, Trough level , Data of drug adjustment, Concurrent medication used, Side effect
• All data was summarized and recorded in case report forms.

Data Analysis and Statistics

The data was analysed by computer using SPSS17 program This study used descriptive statistics ,describing general information, age, results, laboratory results and side effects of the drug in mean ,percentage or standard deviation. And used the chi-square test for analysis of the proportion of patients with serum drug levels within the therapeutic range.

This study used a confidence level of 95%, p-value less than 0.05 was statistically significant.