Isoniazid and Rifampicin as Therapeutic Regimen in the Current Era: A Review

Tuberculosis represents one of the biggest challenges in the medical field. According to World Health Organization (WHO) Global Tuberculosis Report, 2012, there were estimated 8.7 million new TB cases worldwide while 1.4 million people died of TB. Additionally, 90% of the cases of TB are reported in developing countries, with India having the largest number of incident cases. The current treatment method includes the administration of a cocktail of drugs which includes Isoniazid (INH), Rifampicin (RIF), Ethambutol (EMB) and Pyrazinamide (PZA) which are referred to as the first line of drugs. Isoniazid and Rifampicin are currently the two most powerful anti-TB medications. The occurrences of multi-drug and extensive-drug resistant strains (MDR-TB and XDR-TB, respectively) have become a global concern and pose a serious challenge for public health management. Treatment of these resistant cases involves the usage of the second line of anti-tuberculosis drugs which are less effective than the first line and are known to cause adverse reactions or toxic side-effects. Tuberculosis research should not only focus on treatment methods but also on management of the current cases of resistance and measures to prevent an outbreak of resistant TB infection. This review outlines the mechanism of action of isoniazid and rifampicin and how resistance to these drugs emerges. We also provide a brief insight into the prevalence of HIV in TB patients and the challenges associated with treatment regimens in this co-infection.