Objective: There is substantial evidence that tricyclic antidepressants are effective in the management of chronic pain, including cancer pain. In oncological settings, these agents are used as adjuvant analgesic drugs. However, cases of akathisia due to tricyclic antidepressants used as adjuvant analgesic therapy have not previously been reported.
Case reports: Two cancer patients experiencing chronic pain who were refractory to nonsteroidal anti-inflammatory drugs and opioids were prescribed amoxapine as an adjuvant analgesic therapy for neuropathic pain. These patients developed inner restlessness and restless physical movements after amoxapine was prescribed. Although symptoms were atypical, akathisia was suspected and discontinuation of amoxapine resolved the symptoms.
Results and significance of results: Akathisia should be considered in patients receiving adjuvant analgesic therapy with tricyclic antidepressants. Early detection and appropriate treatment will relieve this distressing symptom. Restless movements involving parts of the body other than the legs may be the clue to the diagnosis.