diff --git a/src/Monolog/Formatter/LineFormatter.php b/src/Monolog/Formatter/LineFormatter.php
index d0b4de94a..766fe792c 100644
--- a/src/Monolog/Formatter/LineFormatter.php
+++ b/src/Monolog/Formatter/LineFormatter.php
@@ -180,7 +180,11 @@ protected function replaceNewlines(string $str): string
     {
         if ($this->allowInlineLineBreaks) {
             if (0 === strpos($str, '{')) {
-                return str_replace(array('\r', '\n'), array("\r", "\n"), $str);
+                $str = preg_replace('/(?<!\\\)\\\[rn]/', "\n", $str);
+                if (null === $str) {
+                    $pcreErrorCode = preg_last_error();
+                    throw new \RuntimeException('Failed to run preg_replace: ' . $pcreErrorCode . ' / ' . Utils::pcreLastErrorMessage($pcreErrorCode));
+                }
             }
 
             return $str;