diff --git a/zerver/tests/test_user_topics.py b/zerver/tests/test_user_topics.py
index f90ea280b7..f13be71544 100644
--- a/zerver/tests/test_user_topics.py
+++ b/zerver/tests/test_user_topics.py
@@ -113,23 +113,14 @@ class MutedTopicsTests(ZulipTestCase):
                 topic_name="Verona3",
             )
 
-        # Verify the error handling for the database level
-        # IntegrityError we'll get with a race between two processes
-        # trying to mute the topic.  To do this, we patch the
-        # topic_is_muted function to always return False when trying
-        # to mute a topic that is already muted.
         assert stream.recipient is not None
-        add_topic_mute(
-            user_profile=user,
-            stream_id=stream.id,
-            recipient_id=stream.recipient.id,
-            topic_name="Verona3",
-            date_muted=datetime(2020, 1, 1, tzinfo=timezone.utc),
-        )
+        result = self.api_patch(user, url, data)
 
-        with mock.patch("zerver.views.user_topics.topic_is_muted", return_value=False):
-            result = self.api_patch(user, url, data)
-            self.assert_json_error(result, "Topic already muted")
+        # Now check that error is raised when attempted to mute an already
+        # muted topic. This should be case-insensitive.
+        data["topic"] = "VERONA3"
+        result = self.api_patch(user, url, data)
+        self.assert_json_error(result, "Topic already muted")
 
     def test_remove_muted_topic(self) -> None:
         user = self.example_user("hamlet")
@@ -181,10 +172,6 @@ class MutedTopicsTests(ZulipTestCase):
 
         url = "/api/v1/users/me/subscriptions/muted_topics"
 
-        data: Dict[str, Any] = {"stream": stream.name, "topic": "Verona3", "op": "add"}
-        result = self.api_patch(user, url, data)
-        self.assert_json_error(result, "Topic already muted")
-
         data = {"stream_id": 999999999, "topic": "Verona3", "op": "add"}
         result = self.api_patch(user, url, data)
         self.assert_json_error(result, "Invalid stream ID")
diff --git a/zerver/views/user_topics.py b/zerver/views/user_topics.py
index a19df25aa4..5ec77f0a48 100644
--- a/zerver/views/user_topics.py
+++ b/zerver/views/user_topics.py
@@ -17,7 +17,6 @@ from zerver.lib.streams import (
     access_stream_for_unmute_topic_by_name,
     check_for_exactly_one_stream_arg,
 )
-from zerver.lib.user_topics import topic_is_muted
 from zerver.lib.validator import check_int, check_string_in
 from zerver.models import UserProfile
 
@@ -35,9 +34,6 @@ def mute_topic(
         assert stream_id is not None
         (stream, sub) = access_stream_by_id(user_profile, stream_id)
 
-    if topic_is_muted(user_profile, stream.id, topic_name):
-        raise JsonableError(_("Topic already muted"))
-
     try:
         do_mute_topic(user_profile, stream, topic_name, date_muted)
     except IntegrityError: