Get emergency medical help if you have any of these signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat. Stop using tramadol and call your doctor at once if you have any of these serious side effects:
a red, blistering, peeling skin rash; or
shallow breathing, weak pulse.
Continue taking tramadol and talk to your doctor if you have any of these less serious side effects:
dizziness, drowsiness, weakness;
nausea, vomiting, constipation, loss of appetite;
flushing (redness, warmth, or tingly feeling); or
sleep problems (insomnia).
Side effects other than those listed here may also occur. Talk to your doctor about any side effect that seems unusual or that is especially bothersome.