"Doctors believe the incident was triggered by a change in medication. Senator Kennedy will return home tonight and looks forward to watching the (presidential) debate," the office said in a statement.
Kennedy had a seizure in May and underwent surgery in June for a malignant brain tumor.
The longtime senator and patriarch of America's most fabled political family was diagnosed on May 17 with brain cancer.
He made a dramatic appearance at the Democratic National Convention in Denver last month in support of Democratic presidential candidate Barack Obama.