Methods of treating patients with dyskinesias, by administering a therapeutically effective amount of a dual-action μ-opioid receptor antagonist/κ-opioid receptor agonists or prodrug thereof to a subject in need thereof, sufficient to mitigate the dyskinesia. Alternatively, a combination of both a μ-opioid receptor antagonist or prodrug thereof, and a κ-opioid receptor agonist or prodrug thereof can be administered, either together or separately.