Efficacy of Bilateral Greater Occipital Nerve Block with Lidocaine Hydrochloride in Headache Management Post-Spontaneous Subarachnoid Hemorrhage

The primary objective of this study is to evaluate the **efficacy** of bilateral greater occipital nerve block in the management of headache pain related to **spontaneous subarachnoid hemorrhage** (SAH). This is clinically relevant as headaches are a common and debilitating symptom associated with SAH, and effective management can significantly improve patient quality of life. The intervention involves the use of **lidocaine hydrochloride** as the active substance, compared against a placebo, to assess its therapeutic potential in alleviating headache symptoms in affected individuals.

The clinical trial involves participants experiencing **headache pain related to spontaneous subarachnoid hemorrhage (SAH)**. The study population includes both male and female subjects, with an age range corresponding to categories 3 and 4, which typically encompass adults and older adults. Participants are selected based on specific inclusion criteria, such as being admitted to the Semicritical Care Unit or ICU with diffuse or perimesencephalic aneurysmal SAH and having a Hunt and Hess scale score of 1-3. The trial does not focus on a vulnerable population, and lifestyle factors such as diet and physical activity are not specified as considerations. The sponsor has not provided information regarding the total number of participants in this study.

The clinical trial is designed to evaluate the **efficacy** of bilateral greater occipital nerve block in managing headache pain related to spontaneous subarachnoid hemorrhage (SAH). This study is a randomized, double-blind, controlled trial, classified as a Phase 4 low-intervention study. The investigational drug, **lidocaine hydrochloride**, is administered as a solution for injection, with a maximum daily dose of 3 ml. The trial is expected to commence recruitment on February 28, 2025, and conclude by July 26, 2026.

Participants will undergo a series of study visits, beginning with an inclusion visit where eligibility is confirmed based on criteria such as admission to a specific care unit and a Hunt and Hess scale score of 1-3. Informed consent must be obtained from the patient or their representative. The primary endpoint is a composite variable measuring headache reduction using the Numerical Pain Rating Scale (NPRS) at one hour post-procedure, with a reduction of ≥30% considered a partial response and ≥50% an optimal effect.

Follow-up visits will be scheduled to monitor the participants' response to treatment and any adverse effects. The end-of-study visit will assess the overall efficacy and safety of the intervention. The expected length of participant involvement is approximately one day, given the acute nature of the intervention. Conditions that may lead to early termination from the study include withdrawal of consent or the occurrence of significant adverse events. The trial aims to provide valuable insights into the management of headache pain associated with SAH, utilizing a well-established anesthetic agent in a controlled clinical setting.

The clinical trial involves the administration of **lidocaine hydrochloride** as the experimental medication. The product used is "Lidocaína B. Braun 20 mg/ml solución inyectable," which is a **solution for injection**. The pharmaceutical form is a clear, injectable solution, and the active substance is chemically derived. The administration route is via **subcutaneous injection**. The dosage is set at a maximum of 3 ml per day, with a total maximum dose of 3 ml over the treatment period. The treatment period is limited to one day. The product is manufactured by B.BRAUN MEDICAL, S.A., and is not a pediatric formulation. Compliance with the dosing schedule is monitored to ensure adherence to the protocol.

The non-experimental treatment used in this study is a placebo, which is "Suero Fisiológico Braun 0,9% disolvente para uso parenteral Cloruro de sodio," containing **sodium chloride** as the active substance. This product is also a **solution for injection** and is administered subcutaneously. The placebo is chemically derived and serves as a comparator to the experimental treatment. The dosage and administration schedule for the placebo mirror those of the experimental medication, with a maximum daily dose of 3 ml and a total maximum dose of 3 ml over a one-day treatment period. The placebo is also produced by B.BRAUN MEDICAL, S.A., and is not intended for pediatric use. Participant compliance with the administration of the placebo is similarly monitored to maintain the integrity of the trial results.

The efficacy of the bilateral greater occipital nerve block as a treatment for headache secondary to spontaneous subarachnoid hemorrhage (SAH) will be assessed using a primary endpoint. This endpoint is a composite variable that includes headache reduction measured with the Numerical Pain Rating Scale (NPRS) at 1 hour post-procedure. The efficacy is defined as a ≥30% reduction in headache (partial response) or a ≥50% reduction (optimal effect), evaluated as dichotomous variables (yes/no; n, %). Additionally, the absence of headache within the first hour after the procedure will be considered.