diff --git a/markup/pygments/Makefile.am b/markup/pygments/Makefile.am
index a0f6c21..c17157f 100644
--- a/markup/pygments/Makefile.am
+++ b/markup/pygments/Makefile.am
@@ -1,5 +1,5 @@
 install-exec-local:
-	$(PYTHON) -m pip install $(srcdir)
+	$(PYTHON) -m pip install --prefix=$(prefix) $(PIP_ISOLATION_FLAG) $(srcdir)
 
 EXTRA_DIST = \
     pyrejournal_lexer.py \