Evaluating the Effectiveness of Escalating Intravenous Infusions of Lignocaine and Ketamine in Reducing Pain and Disability for Fibromyalgia Syndrome: A Prospective Observational Study

Introduction: Fibromyalgia is a chronic syndrome characterised by widespread musculoskeletal pain accompanied by fatigue, disability, sleep, memory and mood issues. The pain of fibromyalgia is difficult to manage and has no complete remission. While there is no cure for fibromyalgia, a variety of medications have been tried to minimise symptoms and improve general health. Hence, a trial was conducted to evaluate lignocaine and ketamine as pharmacological modalities to treat fibromyalgia.

Aim: To evaluate effectiveness of intravenous (i.v.) lignocaine-ketamine infusions in reducing pain and disability in fibromyalgia syndrome.

Materials and Methods: A prospective observational study was conducted at Basaveshwara Medical College and Hospital, Chitradurga, Karnataka, India, between March 2021 and March 2022, on patients aged between 18-60 years diagnosed with fibromyalgia syndrome. Sixty patients were included in the study. Escalating doses of i.v. lignocaine of 5 mg/kg, 6 mg/kg and 7 mg/kg followed by escalating doses of i.v. ketamine of 0.4 mg/kg, 0.5 mg/kg and 0.6 mg/kg were administered on alternate days over a period of 12 days. Infusions were given in 50 mL normal saline through syringe pump over a period of 45 minutes. Pre and postinfusion 11 point Numerical Rating Scale (NRS) score was used to assess pain and World Health Organisation Disability Assessment Schedule (WHODAS) 2.0 score to assess disability. Data are presented as mean and standard deviation. Statistical analysis was done by using the t-test for pre and post-treatment score, with a p-value<0.05 was considered statistically significant.

Results: The present study showed female predominance of 42 out of 60 patients (70%) compared to males 18 out of 60 (30%). Pretreatment average baseline NRS score was 8.8. The mean reduction in NRS scores after lignocaine-ketamine infusions at the end of one month was 1.40 and at sixth month 1.25 which was statistically significant (p-value=0.001). Pretreatment mean average disability score was 2.70 and at the end of sixth month it was 0.59 which was statistically significant (p-value=0.001). Three patients did not have reduction in NRS scores and reported mild to moderate side-effects in the form of dizziness, headache and raised blood pressure.

Conclusion: Combined infusions of lignocaine-ketamine resulted in significant reduction in pain and disability in patients with fibromyalgia. Higher and repeated doses seem to be more effective and resulted in longer pain relief. Long-term follow-up periods are needed to determine the effectiveness, dose response and safety of these infusions as a therapeutic modality for fibromyalgia.