Children who were given oral arginine supplements during vaso-occlusive crises as a result of SCD reported lower levels of pain, required less pain medication, and were discharged from the hospital earlier than those given a placebo, on average, in a clinical trial conducted in Nigeria.

Nigeria has a larger population of people with SCD than any other country. The study bolsters the evidence that arginine enhances the effectiveness of other pain medications and suggests arginine could help improve SCD management in Nigeria and other African countries with limited resources and a high prevalence of SCD, according to researchers.

“Arginine is a cheap, readily available over-the-counter supplement,” said senior study author Richard Onalo, FCPaed, University of Abuja, Nigeria. “Oral arginine is a safe and useful product in patients experiencing painful crises. The supplement adds to the pain killing ability of conventional drugs, and may lead to faster resolution of a crisis and a shorter hospital stay.”

Arginine, an amino acid, is a key building block for nitric oxide, a bio-regulatory molecule that relaxes blood vessels. During a vaso-occlusive crisis, small blood vessels in affected parts of the body become obstructed, depriving tissues of oxygen. At the same time, concentrations of arginine drop precipitously, limiting the body’s ability to produce nitric oxide and reopen the obstructed blood vessels.

Only a few previous studies have investigated the use of arginine supplements to replenish depleted arginine and help resolve vaso-occlusive crises. One U.S. trial found children given intravenous arginine when hospitalized for SCD-related pain had a significant decrease in pain and opioid use compared to placebo. The new study is the first conducted in Africa and the first to test the use of arginine supplements delivered orally, rather than through an injection, for acute pain control, Dr. Onalo said.

The researchers enrolled 68 children hospitalized for vaso-occlusive crises at two hospitals in Abuja, Nigeria. Half were given oral arginine every eight hours until hospital discharge or up to 15 doses total, while half were given a placebo on the same schedule.

Children given arginine had their pain decline more quickly, reached the end of their vaso-occlusive crisis faster, and required less total pain medication overall, though the decrease in total opioid dose was not statistically significant. More than half of children receiving arginine were discharged from the hospital by day five while only a quarter of children receiving placebo were discharged by that point.

The researchers observed no difference between the groups in terms of serious adverse events, though children receiving arginine were more likely to experience vomiting. The arginine supplement is unpalatable, Dr. Onalo noted, though the taste typically can be masked by mixing the supplement with Gatorade or grape juice.

Taken together, the new study and the previous trial of intravenous arginine in the U.S. make a strong case for further research, Dr. Onalo said. For example, future studies could help to determine whether giving oral arginine supplements at home at the onset of crisis or in the hospital for those already on admission could prevent hospitalizations and readmissions in children with SCD-related pains. Additionally, future studies could examine the use of oral arginine supplementation in adults with SCD and assess how disease severity, race, and location affect the benefits of arginine for managing vaso-occlusive crises.

This article is a news release from American Society of Hematology Annual Press Meeting. Read the original here.