diff --git a/lib/AktiveMerchant/Http/Adapter/cUrl.php b/lib/AktiveMerchant/Http/Adapter/cUrl.php
index f51887c..a647b54 100644
--- a/lib/AktiveMerchant/Http/Adapter/cUrl.php
+++ b/lib/AktiveMerchant/Http/Adapter/cUrl.php
@@ -228,7 +228,7 @@ protected function apply_options(RequestInterface $request)
         );
 
         $config = $this->map_config($request->getConfig());
-        $this->options = $this->options + $config + $default;
+        $this->options = array_replace($this->options, $config, $default);
 
         curl_setopt_array($this->ch, $this->options);
     }
diff --git a/tests/AktiveMerchant/Http/Adapter/cUrlTest.php b/tests/AktiveMerchant/Http/Adapter/cUrlTest.php
index fc80b85..d82ec46 100644
--- a/tests/AktiveMerchant/Http/Adapter/cUrlTest.php
+++ b/tests/AktiveMerchant/Http/Adapter/cUrlTest.php
@@ -5,8 +5,9 @@
 namespace AktiveMerchant\Http\Adapter;
 
 use AktiveMerchant\Mock\Request;
+use PHPUnit_Framework_TestCase;
 
-class cUrlTest extends \PHPUnit_Framework_TestCase
+class cUrlTest extends PHPUnit_Framework_TestCase
 {
     public function testAdapterConfig()
     {
@@ -26,4 +27,26 @@ public function testAdapterConfig()
 
         $this->assertEquals(20, $options[CURLOPT_CONNECTTIMEOUT]);
     }
+
+    /**
+     * @throws Exception
+     */
+    public function testItShouldOverrideOptionsOnConcurrentRequests()
+    {
+        $request = new Request();
+        $adapter = new cUrl();
+
+        $request->setUrl('http://www.httpbin.org/get');
+        $adapter->sendRequest($request);
+
+        $concurrentRequestUrl = 'https://www.examples.com/';
+        $request->setUrl($concurrentRequestUrl);
+        $adapter->sendRequest($request);
+        $concurrentOptions = $adapter->getOptions();
+
+        $this->assertEquals(
+            $concurrentRequestUrl,
+            $concurrentOptions[10002]
+        );
+    }
 }