Terapi tuberkulosis (TB) menggunakan beberapa antibiotik yang sering diberikan dalam Kombinasi Dosis Tetap (KDT) kategori I dan II berdasarkan Directly Observed Treatment Short-course (DOTS). Kombinasi berbagai jenis obat antituberkulosis (OAT) dan durasi terapi yang lama bisa menimbulkan efek samping. Tujuan penelitian ini adalah untuk mengetahui gambaran dan frekuensi efek samping OAT kategori I dan II. Penelitian cross-sectional ini mengambil data dari rekam medis pasien TB paru dewasa di Klinik DOTS Rumah Sakit Dr. Hasan Sadikin Bandung, Indonesia, pada periode Juli 2015–Juni 2016. Data yang diambil adalah jenis TB, jenis OAT, efek samping dan waktu kemunculan efek samping. Dari 178 pasien, 27 pasien (15,2%) mengalami efek samping. Jumlah pasien dengan OAT kategori I yang mengalami efek samping sebanyak 22 pasien, sedangkan OAT kategori II sebanyak 5 pasien. Efek samping terbanyak adalah hepatotoksisitas. Efek samping di kategori I paling banyak adalah hepatotoksisitas (52%) sedangkan di kategori II frekuensinya sama yaitu 20% yang terdiri dari hepatotoksisitas, gangguan gastrointestinal, ruam dan gatal, gangguan neurologi dan gagal ginjal. Efek samping pada kategori I banyak terjadi di bulan pertama (48%), sedangkan kategori II banyak terjadi di bulan pertama dan kedua yang masing-masing adalah 40%. Efek samping tidak berhubungan dengan usia dan jenis kelamin (nilai p>0,05). Kesimpulan penelitian ini adalah kejadian efek samping OAT kategori I dan II bervariasi dan terdapat 27 pasien yang mengalami satu atau lebih efek samping dengan efek samping terbanyak adalah hepatotoksisitas.Kata Kunci: Efek samping, obat antituberkulosis, tuberkulosis paru Adverse Reactions of Category I and II Regimens of Anti-tuberculosis Drugs among Adult Pulmonary Tuberculosis Patients in Hasan Sadikin General HospitalAbstractAnti-tuberculosis therapy (ATT) with multiple antibiotics, administered as category I and II regimens fixed dose combination (FDC) which based on Directly Observed Treatment Short-course (DOTS) is commonly used. Since the process of this treatment is long-term and consists of multidrug, adverse reaction may occur. The aim of this study was to find the description and frequency of adverse reactions during the therapy of category I and II regimens of ATT. This cross-sectional study used data which was taken from adult pulmonary TB medical record at DOTS clinic of Hasan Sadikin General Hospital, Bandung, Indonesia, in the period of July 2015–June 2016. The data consisted of type of TB, drug choice, adverse effect and the time of emergence. Among 178 patients, 27 patients (15.2%) experienced adverse effects which consisted of 22 patients in category I regimens and 5 patients in category II regimens. The majority of adverse effects is hepatotoxicity. Adverse effects occurred in category I regimens mostly was hepatotoxicity (52%) and in category II regimens were hepatotoxicity, gastrointestinal disorder, skin reactions, neurological disorder and renal failure, with each frequency was 20%. Adverse effects in category I regimens mostly occurred in first month (48%) and in category II regimens mostly occurred in first and second month, with both frequencies were 40%. Side effects were not related to age and sex (p-value >0.05). The conclusion of this study is there were various pattern of adverse reactions of category I and II regimens of ATT. A total of 27 patients experienced one or more adverse reactions, the most frequent reaction was hepatotoxicity.Keywords: Adverse effects, anti-tuberculosis drugs, pulmonary tuberculosis