This study comparatively investigated the toxicological effects of treatment with efavirenz, isoniazid and efavirenz-isoniazid (EFV-INH) combination on liver function parameters and histology of adult male albino rats. Animals used in this study were divided into five (5) groups A-E of sixteen (16) animals each. Animals in group A (placebo control) were treated with water while animals in group B (solvent control) were treated with arachis oil orally. Animals in groups C-E were treated orally with 15mg/kg of INH, 10mg/kg of EFV and a combination of INH-EFV for 2-8 weeks respectively. At the end of drug therapy, serum was extracted from centrifuged blood sample and evaluated for alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, total and conjugated bilirubin. Animals were sacrificed and liver was harvested, weighed and evaluated for histopathological changes. Effects produced by co-treatment with EFV-INH on absolute liver weight, alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, conjugated and total bilirubin were insignificant (p>0.05) when compared to effects produced by treatment with individual doses of EFV and INH. Histopathological evaluation of the liver of animals treated with EFV-INH combination showed vascular congestion, inflammation of parenchyma and hepatocytes degeneration. These results show that co-therapy with EFV-INH in patients with human immunodeficiency virus /tuberculosis co-infection may not be associated with synergistic hepatotoxicity.

This experimental study comparatively evaluated the toxicological effects of treatment with tenofovir, rifampicin and tenofovir-rifampicin (TDF-RIF) combination on kidney function and histology of male albino rats. Male albino rats used in this study were divided into five (5) groups A-E of sixteen (16) animals each. Animals in group A, (placebo control) were treated orally with normal saline, group B (solvent control) were treated orally with 0.1% ethanol while groups C-E were treated orally with 80 mg/kg of RIF, 32 mg/kg of TDF and a combination of TDF-RIF for 2-8 weeks respectively. Animals were sacrificed at the end of drug therapy, blood sample was collected, centrifuged and serum extracted for creatinine, urea and, uric acid evaluation. Kidney was harvested, weighed and examined for histopathological changes. Treatment with tenofovir-rifampicin combination had no significant (p<0.05) effect on absolute kidney weight when compared with treatment using individual doses of these drugs. Insignificant (p>0.05) time-dependent increases in serum creatinine, urea and uric acid levels were observed in animals treated with tenofovir-rifampicin combination when compared with treatment using individual doses of these drugs. Acute tubular necrosis, enlarged glomeruli and obliteration of the Bowman's capsule were observed in the kidneys of rats treated with tenofovir, rifampicin and a combination of tenofovir-rifampicin. This result shows that treatment with tenofovir-rifampicin combination in the management of human immunodeficiency virus /tuberculosis (HIV/TB) co-infection may not be associated with synergistic renal toxicity at the dose level used in this study.