Isoniazid acetylation phenotypes in the Sudanese population; findings and implications

Isoniazid (INH) is the mainstay antimicrobial in the treatment of tuberculosis (TB). It is acetlylated in the liver to acetyl-INH. However, there is variation in rate of acetylation of INH among TB patients (i.e. fast, intermediate or slow acetylators) which impacts on the treatment outcomes.

The isoniazid acetylation phenotypes in the expatriate Sudanese population were determined to provide future guidance since TB is prevalent in Sudan.

A community-based trial among Sudanese expatriates in Saudi Arabia was undertaken to identify INH-acetylation phenotypes. After overnight fasting, a single dose of 200 mg of INH was given to the volunteers. Three hours later, 5 ml of blood were drawn from each volunteer and prepared for High-Performance Liquid Chromatography (HPLC) analysis. The main outcomes were INH and Acetyl-INH concentrations in plasma and the subsequent Acetyl-INH/INH metabolic ratio (MR).

The findings suggest that slow acetylation is highly prevalent among the study participants (n = 43; 84.31%). Moreover, there was no statistically significant correlation between age and the MR (r = -0.18, P = 0.20). Further, there was no significant association between gender and the MR (P = 0.124). Similarly, no significant association was found between smoking habits and MR (P = 0.24).

Isoniazid phenotyping suggests predominantly slow acetylation among the Sudanese in this sample. The study found no statistically significant associations between the MR and age or gender or smoking.