Efficacy and safety of oral Nigella sativa oil for symptomatic treatment of knee osteoarthritis: A double-blind, randomized, placebo-controlled clinical trial

Abstract

Background and purposeThe oil of Nigella sativa (NS) seeds has analgesic and anti-inflammatory effects. Therefore, the efficacy and safety of NS oil in the treatment of knee osteoarthritis were evaluated. Materials and methodsOne hundred and sixteen patients aged 50–70 years were randomly assigned to take 2.5 mL NS oil (N = 58) or placebo (N = 58) orally every 8 h for 1 month. WOMAC (Western Ontario and McMaster Universities Osteoarthritis Index) was the primary outcome measure and Visual Analog Scale (VAS) for pain, number of 500 mg acetaminophen tablets taken per day during the trial, patients’ satisfaction with the interventions, complete blood count and the blood levels of alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, creatinine and blood urea nitrogen were the secondary outcome measures. ResultsFifty two and 54 patients respectively in the NS oil and placebo groups completed the study. The VAS scores were decreased by 33.96 ± 17.04% (NS oil group) and 9.21 ± 0.32% (placebo group) (p < 0.001), and WOMAC total scores were decreased by 27.72 ± 18.61% (NS oil group) and 1.34 ± 2.31% (placebo group) (p < 0.001) compared to baseline. The NS oil reduced the dose of acetaminophen significantly compared with the placebo (p = 0.001). The patients were significantly more satisfied with the NS oil than the placebo (p < 0.001). The NS oil had no significant effect on the other variables. There was no side effect. ConclusionOral NS oil safely reduces the osteoarthritis symptoms and analgesic dose in the knee osteoarthritis patients.