diff --git a/opentelemetry-api/src/opentelemetry/metrics/_internal/instrument.py b/opentelemetry-api/src/opentelemetry/metrics/_internal/instrument.py
index f98cbd72430..b203b8ffe7c 100644
--- a/opentelemetry-api/src/opentelemetry/metrics/_internal/instrument.py
+++ b/opentelemetry-api/src/opentelemetry/metrics/_internal/instrument.py
@@ -18,7 +18,6 @@
 from abc import ABC, abstractmethod
 from dataclasses import dataclass
 from logging import getLogger
-from re import ASCII
 from re import compile as re_compile
 from typing import (
     Callable,
@@ -39,8 +38,8 @@
 
 _logger = getLogger(__name__)
 
-_name_regex = re_compile(r"[a-zA-Z][-.\w]{0,62}", ASCII)
-_unit_regex = re_compile(r"\w{0,63}", ASCII)
+_name_regex = re_compile(r"[a-zA-Z][-_.a-zA-Z0-9]{0,62}")
+_unit_regex = re_compile(r"[\x00-\x7F]{0,63}")
 
 
 @dataclass(frozen=True)
diff --git a/opentelemetry-api/tests/metrics/test_instruments.py b/opentelemetry-api/tests/metrics/test_instruments.py
index ff2ab2b3e52..3e1e3fe745d 100644
--- a/opentelemetry-api/tests/metrics/test_instruments.py
+++ b/opentelemetry-api/tests/metrics/test_instruments.py
@@ -571,6 +571,7 @@ def test_name_regex(self):
         self.assertTrue(instrument._check_name_and_unit("a.", "unit")[0])
         self.assertTrue(instrument._check_name_and_unit("a-", "unit")[0])
         self.assertTrue(instrument._check_name_and_unit("a_", "unit")[0])
+
         self.assertFalse(instrument._check_name_and_unit("a" * 64, "unit")[0])
         self.assertFalse(instrument._check_name_and_unit("Ñ", "unit")[0])
         self.assertFalse(instrument._check_name_and_unit("_a", "unit")[0])
@@ -582,5 +583,7 @@ def test_unit_regex(self):
         instrument = ChildInstrument("name")
 
         self.assertTrue(instrument._check_name_and_unit("name", "a" * 63)[1])
+        self.assertTrue(instrument._check_name_and_unit("name", "{a}")[1])
+
         self.assertFalse(instrument._check_name_and_unit("name", "a" * 64)[1])
         self.assertFalse(instrument._check_name_and_unit("name", "Ñ")[1])