Greater Occipital Nerve Block For Treatment of Medication Overuse Headache: A Randomized double blind placebo controlled study

Medication-overuse headache is also known as analgesic rebound headache, drug-induced headache or medication-misuse headache. When patients with established primary headache disorders like migraine or tension-type headaches overuse medication for their acute headaches, medication-overuse inadvertently increases the frequency and intensity of their headaches, creating a vicious cycle of further drug consumption and increase in their headache frequency eventually transforming their headache from migraine or tension-type headache to medication-overuse headache. Greater occipital nerve blockade (GONB) is postulated to modulate the pain pathway through its connections at trigemino-cervical complex (TCC). Prior to treatment, subjects will participate in a run-in period where they are instructed to record their pain on a visual analogue scale of 0 to 10 as well as hours of pain free time per day in a paper daily diary for one month (4 weeks) and headache disability assessed by HIT 6 questionnaire to ensure an adequate baseline for comparison. Patient will be continued on any previous prophylaxis medication however any acute treatment taken by patients fulfilling the duration for abuse will be stopped. However, any rescue medication taken by the patient during follow-up period will be noted in both arms and the frequency and dosage will be analysed at the end of study. Eligible participants will undergo Randomization, and patients will be allocated to groups A or B (1:1) by investigator 1 into case (those who receive GONB 2ml 2% lignocaine bilaterally) and control (those who do not receive intervention) groups. The study will be a prospective study and assessment will be done by investigator 2, unaware of the treatment received by both group (blinded end point) at week 4 and week 8 post GONB with Primary outcome being 50% reduction in headache frequency and Secondary outcome being 50% reduction in headache severity based on VAS score and Impact on functional disability based on HIT-6 questionnaire.