A known sputum positive pulmonary tuberculosis patient currently on INH, rifampicin, pyrizinamide and ethambutol is found to be HIV positive. His CD4 count is 100 /dl and viral load is more than 50,000 copies/ml. Which of the following antiretroviral drug should be avoided in this patient?

Ritonavir a protease inhibitor should be avoided from the treatment of HIV, in a patient receiving rifampicin as a pa of antituberculosis treatment regime. Rifampin is a potent hepatic enzyme inducer. When this is co administered with a protease inhibitor, it decrease the availability of the drug upto 80%. This resulting low concentration of the drug promotes the development of drug resistance and treatment failure. Ref: Antiretroviral Therapy By Erik De Clercq, Page 347