en General پژوهشي Research Article <div style="text-align: justify;"><span style="font-size:14px;"><span style="font-family:Times New Roman;"><strong>Background:</strong>Inducing analgesia in patients is a primary goal of anesthesia, achieved through various methods and drugs.<br> <strong>Objectives:</strong>The present study compares the block quality and complications associated with different doses of Marcaine and fentanyl during spinal anesthesia for leg fracture surgery in opium abusers.<br> <strong>Methods:</strong>In this randomized clinical trial, 80 patients with a history of opium abuse, classified as American Society of Anesthesiology (ASA) class I or II, who presented with leg fractures at Vali-Asr Hospital in 2020 - 2021, were selected through convenience sampling and randomly assigned to two groups. Group A (40 patients) received 15 mg of Marcaine and 10 &mu;g of fentanyl intrathecally. Group B (40 patients) received 12.5 mg of Marcaine and 25 &mu;g of fentanyl intrathecally. The duration of sensory block, incidence of nausea, vomiting, shivering, itching, and duration of painlessness were recorded on a checklist for both groups. Data were analyzed using chi-square and independent t-test in SPSS version 21 software (P = 0.05).<br> <strong>Results:</strong>Eighty leg fracture patients participated. There were no significant differences in age, gender, or anesthesia class between the two groups. The duration of motor block return was significantly longer in group A compared to group B (115.23 &plusmn; 42.71 vs. 63.35 &plusmn; 24.5 minutes) (P < 0.001). Group B had a longer duration of analgesia (148 &plusmn; 27 minutes) compared to group A (90 &plusmn; 34 minutes). There was no significant difference in complications (nausea, vomiting, shivering, and itching). Visual Analog Scale (VAS) scores were lower in group B than in group A (P < 0.001). Group A had significantly higher average pethidine consumption compared to group B.<br> <strong>Conclusions:</strong>Higher fentanyl doses resulted in less pain without increasing complications. This method is recommended for spinal anesthesia in addicted patients.</span></span></div> Marcaine,Fentanyl,Block Quality,Spinal Anesthesia,Opium Abuser 0 0 http://mcj.bums.ac.ir/browse.php?a_code=A-10-1-311&slc_lang=en&sid=1 Bibi Fatemeh Shakhs Emampour 10031947532846004884 10031947532846004884 No Department of Anesthesia, Birjand University of Medical Sciences, Birjand, Iran Somayeh Sabaghian 10031947532846004885 0009-0003-6192-6691 No Department of Anesthesia, Mashhad University of Medical Sciences, Mashhad, Iran Dorsa Abbasi 10031947532846004886 0009-0009-3420-2579 No Student Research Committee, Birjand University of Medical Sciences (BUMS), Birjand, Iran Bita Bijari bita.bijari@yahoo.com 10031947532846004887 10031947532846004887 Yes Department of Community Medicine, Cardiovascular Diseases Research Center, School of Medicine, Birjand University of Medical Sciences, Birjand, Iran