Hello, I'm Dr. Deb and will do my best to help you today.
I'm sorry for this concern for your Dachshund.
Fortunately, there's quite a wide range of dosages for Tramadol which means that it's highly unlikely that the dose you gave him/her would be anywhere near a toxic one. So while the Dachshund probably received a double dose from what he/she would normally be given, this shouldn't be a problem.
Signs which might be seen (even with a normal dose) include excessive sedation, agitation, anxiety, tremor, dizziness or GI effects such as inappetence, vomiting, constipation to diarrhea).
Should any of these signs develop, they'll resolve within about 24-36 hours or less.
I hope this helps to reassure you. Deb