A Randomized cross-over controlled trial comparing the bioavailability of a single oral dose of rifampicin in smoking male volunteers with or without TB / Angelin F. Apostol, Michell B. Cruz, Crispin Reynaldo B. Abarientos, Archiebald M. Bonagua, Anthony G. Borlongan, Catherine B. Bueno, Lea Riza P. Catre, Lani D. Cayabayab, Edward Vincent R. Cheng, Aileen D. Danga, Maribeth R. De Leon, Giselle D. Dizon, Winston S. Eduarte, Elmer I. Esguerra, Zilpha Florida E. Felix, Robert T. Gonzales, Jenefer H. Hernandez, Karen May P. Lorenzo, Maria Gracia A. Mabasa and Lerma C. Magundayao.

Includes appendices and bibliographical references.

Abstract: Tuberculosis remains a frequently encountered disease entity. After the advent of chemotherapy, a dramatic decrease in the incidence of the pulmonary disease had been observed. The primary agents used in the treatment are isoniazid, rifampicin, ethambutol, streptomycin, and pyrazinamide. Of these, rifampicin has the most promising effects on the tubercle bacilli because of the less development of resistant strains it. The primary aim of this study is to determine if smoking has a corresponding effect on the rate of bioavailability of rifampicin between TB patients and non-TB patients. The methodology is divided into three phases: history and physical examination, laboratory work-up and the blood analysis after the oral rifampicin and placebo intake. After the selection process, 20 selected patients, 21-70 yrs. old male smokers, underwent extensive physical examination conducted by a physician. Out of the 20 patients screened, 14 patients passed and underwent laboratory work-up that included CBC, blood chemistries, urinalysis, AFB stain, ECG and chest x-ray. Among the 14 patients, 9 of them proceeded to the experiment proper wherein they were divided into two groups: one for rifampicin and another for placebo. After two weeks, there was a cross-over among the two groups. The experiment proper was a double-blind study, wherein the patient and the examiner were blinded into which group they are in. After each intake, plasma samples at different intervals were taken and were analyzed using the simplified solid phase extraction technique. Out of the nine patients, five were suspected to have TB as manifested in their history, physical examination and laboratory results. Their drug assay result in the first session showed a mean plasma rifampicin concentration of 3.6856 ug/ml and the second session, 1.6852 ug/ml. On the other hand, the four non-TB patients on the first session had a mean plasma rifampicin concentration of 11.2536 ug/mL and the second session, 4.7732 ug/mL. The data collected were statistically analyzed using the Two-tailed t-test with an a = 0.05 and a critical value = + 2.704. The t-test result obtained on the first session was 3.1826 and for the second session, 28211. Therefore, mean plasma rifampicin concentrations of TB and non-TB smokers on the two sessions showed that there is a statistically significant difference in rifampicin bioavailability between the two groups.

Thesis - Department of Community & Family Medicine