Why does ibuprofen 600 mg make you drowsy?

Answer 1

In general, ibuprofen does not cause drowsiness. There are some people who might be affected by the medication in a way that is not standard, so it is possible that it could cause drowsiness in rare cases.

Answer 2

Symptoms of overdose are abdominal pain, nausea, vomiting, drowsiness, dizziness, and headache. 600 mg is very unlikely to be an overdose, the drowsiness can be a side effect in some.