foreach (string item in HttpContext.Current.Request.Headers)
{
     if (string.IsNullOrWhiteSpace(item)) continue;

     if (item == "HTTP_X_NEWRELIC_TRANSACTION" || item == "HTTP_X_NEWRELIC_ID")
     {
            HttpContext.Current.Response.StatusCode = 403; //Forbidden  
            HttpContext.Current.Response.End();
     }
}