diff --git a/c-user/interrupt_manager.rst b/c-user/interrupt_manager.rst
index 5882261..11293f6 100644
--- a/c-user/interrupt_manager.rst
+++ b/c-user/interrupt_manager.rst
@@ -199,9 +199,6 @@ is a list of RTEMS system calls that may be made from an ISR:
   - rtems_clock_get_ticks_per_second
   - rtems_clock_get_ticks_since_boot
   - rtems_clock_get_uptime
-  - rtems_timecounter_tick
-  - rtems_timecounter_simple_downcounter_tick
-  - rtems_timecounter_simple_upcounter_tick
 
 - Timer Management