Pain Management in Children and Young Adults With Sickle Cell Disease

This is a phase II double-blind placebo-controlled clinical trial evaluating the effect of gabapentin when added to standard pain management for patients with sickle cell disease experiencing acute pain crisis in the ambulatory care setting. Sickle cell pain is different for every patient. Some patients get complete relief from routine pain medicines, and others need more time or more doses of pain medicines before the pain goes away completely. It is known that humans have many types of pain, including something called neuropathic pain. Neuropathic pain in other conditions (such as diabetes) has been treated successfully with a medicine called gabapentin. The investigators in this study suspect that some sickle cell pain is a combination of pain types. They would like to see if adding gabapentin to the usual pain medicines makes pain go away faster or more completely. Primary Objective: * To assess the analgesic efficacy of gabapentin vs. placebo for pain during vaso-occlusive crisis (VOC) in participants with sickle cell disease (SCD). A response to study drug will be defined by a decrease in pain score of ≥ 33% between presentation to the acute care setting and assessment at 3 hours post administration of study drug. Secondary Objective: * To compare the total morphine equivalent dose (mg/kg) used to control pain during VOC between presentation to the acute care setting and assessment at 3 hours post administration of study drug in the gabapentin vs. placebo groups.