diff --git a/examples/requirements.txt b/examples/requirements.txt
index 2eb5a0b..83db150 100644
--- a/examples/requirements.txt
+++ b/examples/requirements.txt
@@ -6,6 +6,7 @@
 alabaster==0.7.6
 Babel==2.1.1
 docutils==0.12
+gevent_subprocess==0.1.2
 Jinja2==2.8
 MarkupSafe==0.23
 Pygments==2.0.2
@@ -14,6 +15,7 @@ six==1.10.0
 snowballstemmer==1.2.0
 Sphinx==1.3.3
 sphinx-rtd-theme==0.1.9
+zope.interface==4.2.0
 
 # VSC repositories
 [-e] git+git://git.myproject.org/MyProject#egg=MyProject # Git
diff --git a/syntax/requirements.vim b/syntax/requirements.vim
index a5b9bcf..3bb66a1 100644
--- a/syntax/requirements.vim
+++ b/syntax/requirements.vim
@@ -12,7 +12,7 @@ syn case match
 syn region requirementsComment start="[ \t]*#" end="$"
 syn match requirementsCommandOption "\v^\[?--?[a-zA-Z\-]*\]?"
 syn match requirementsVersionSpecifiers "\v(\=\=\=?|\<\=?|\>\=?|\~\=|\!\=)"
-syn match requirementsPackageName "\v^[a-zA-Z][a-zA-Z\-0-9]*"
+syn match requirementsPackageName "\v^[a-zA-Z][a-zA-Z\-_\.0-9]*"
 syn match requirementsVersionControls "\v(git\+?|hg\+|svn\+|bzr\+)\S+"
 
 hi link requirementsComment Comment