Taking a stray dose of a medicine that isn't yours once isn't usually addictive or harmful if you have no allergy to it. These are not habit-forming drugs, so one mistaken dose won't start a dependency or a "course" you need to continue.
Next Steps
If you feel fine and have no other health conditions or regular medicines, no action is needed. Mention it to your doctor if you're on something else regularly, so they can rule out any interaction.
Health Tips
Watch for any new symptoms like dizziness, rash or unusual tiredness over the next day or two, and see a doctor if they appear.