The aim of this study was to determine the relapse rate and failure rate in the regimen of less than 6-months and this regimen was compared with the 6 month regimen. This study was an experimental clinical trial on one hundred of patients with pulmonary tuberculosis at Zahedan (a city in Southeast of Iran) in a time period of 5 years from August 1996. The study patients were adults with newly diagnosed, sputum smear positive pulmonary tuberculosis, who had no cavitation and no abnormality in more than one lobe on plain chest X-ray. Eligible patients were randomly allocated to one of the following regimens: (A) Isoniazid, Rifampicin, Pyrazinamide and Ethambutol daily for 2 months, followed by Isoniazid and Rifampicin daily for 2 months: (B) Isoniazid, Rifampicin, Pyrazinamide and Ethambutol daily for 2 months, followed by Isoniazide and Rifampicin daily for 4 months. The patients were assessed clinically and bacteriologically every month during treatment and every two months after treatment. Follow up was continued for 5 years. The results up to 5 years after treatment are presented here. Thirty three cases were treated with the 4- month regimen and 67 cases treated with the 6 month regimen. Then the relapse and failure rate was compared together for the two regimens. Over a follow-up period of 5 years, among the patients who were entered into the 4 month regimen (A), the relapse rate was 9.09% (3 cases) and the failure rate was zero. The relapse and failure rates in the 6- month regimen (B) were 8.95% (6 cases) and 4.48% (3 cases), respectively. This results showed that, there was no significant difference between two regimens in the relapse rate and the failure rate (p>0.05). Regimen of 4 months duration can achieve a high cure rate and low 5 years relapse rate in newly diagnosed patients with smear positive pulmonary tuberculosis where, there is not any report of drug resistance. Larger studies are needed to confirm these results.
Batool Sharifi-Mood , Malihe Metanat , Roya Alavi-Naini , Hamid-Reza Kouhpayeh , Masoud Salehi , Mohammad Naderi , S. Mohammad Hashemi -Shahri and Taghi Naser-Poor , 2006. The Comparison of Six-month and Four-month Regimens of Chemotherapy in the Treatment of Smear Positive Pulmonary Tuberculosis. Journal of Medical Sciences, 6: 108-111.