Background: Trigeminal neuralgia (TN) is considered one of the most debilitating disorders. Several medications such as anticonvulsants are available to provide relief from pain. In this study we used either ketamine which acts as an antagonist to N-methyl-d-aspartate receptors, or lidocaine which can block sodium channels in controlling of refractory trigeminal neuralgia.
Aim: The primary outcome of the study was the pain score (The NRS) for pain assessment during the 12-week study period. The secondary outcomes were (1) Amount of analgesic medications (2) Frequency of pain (3) descriptors of pain.
Methods: This study was conducted on 100 adult patients (aged 20-70 years) with refractory trigeminal neuralgia. Patients were enrolled into two groups each group contain 50 patients. In group I (ketamine group), patients underwent ketamine infusion protocol which consisted of 3 sessions of ketamine infusion in a dose of 0.4 mg/Kg over 30-45 minutes in 250 mL of 5% dextrose solution, and each session was performed consecutively every 4 days. In group II (lidocaine group), patients underwent lidocaine infusion protocol which consisted of 3 sessions of lidocaine infusion in a dose of 5 mg/kg over 30-45 minutes in 250 mL of 5% dextrose solution, and each session was performed consecutively every 4 days.
Results: Our results showed that both groups were comparable regarding age, gender and site of pain. A significantly longer duration of pain relief was noticed in group I when compared to group II at 2 weeks, 1 month, 2 months and 3 months (3.11 ± 2.01, 3.15 ± 1.23, 4.23 ± 1.12, 4.50 ± 1.02) p<0.001. Immediately after infusion, 12 h and at 24 h pain relief was highly significant decreased in lidocaine group when compared to ketamine group (1.27 ± 1.11, 1.67 ± 1.48, 2.35 ± 1.25) p<0.001. At 48 h there was decrease in pain scores in both groups when compared to pre infusion values but without any statistical significance (3.25 ± 1.24, 3.56 ± 1.25) p=0.216. The analgesic consumption was significantly decreased in ketamine group. Complications were minor and self-controlled.
Conclusion: The infusion of either ketamine or lidocaine controls pain in refractory trigeminal neuralgia and decreases anticonvulsant consumption with minimal post- infusion complications but with the upper hand to ketamine.