Pharmacovigilance in hospice/palliative care: Net effect of amitriptyline or nortriptyline on neuropathic pain:...

Real-world effectiveness of interventions in palliative care need to be systematically quantified to inform patient/clinical decisions. Neuropathic pain is prevalent and difficult to palliate. Tricyclic antidepressants have an established role for some neuropathic pain aetiologies, but this is less clear in palliative care.

To describe the real-world use and outcomes from amitriptyline or nortriptyline for neuropathic pain in palliative care.

An international, prospective, consecutive cohort post-marketing/phase IV/pharmacovigilance/quality improvement study of palliative care patients with neuropathic pain where the treating clinician had already made the decision to use a tricyclic antidepressant. Data were entered at set times: baseline, and days 7 and 14. Likert scales graded benefits and harms.

Twenty-one sites (inpatient, outpatient, community) participated in six countries between June 2016 and March 2019. Patients had clinician-diagnosed neuropathic pain.

One hundred and fifty patients were prescribed amitriptyline (110) or nortriptyline (40) of whom: 85% had cancer; mean age 73.2 years (SD 12.3); mean 0-4 scores for neuropathic pain at baseline were 1.8 (SD 1.0). By day 14, doses of amitriptyline were 57 mg (SD 21) and nortriptyline (48 mg (SD 21). Fifty-two (34.7%) patients had pain improvement by day 14 (amitriptyline (45/110 (43.3%); nortriptyline (7/40 (18.9%)). Thirty-nine (27.7%) had new harms; (amitriptyline 29/104 (27.9%); nortriptyline 10/37 (27.0%); dizziness (n = 23), dry mouth (n = 20), constipation (n = 14), urinary retention (n = 10)). Benefits without harms occurred (amitriptyline (26/104 (25.0%); nortriptyline (4/37 (10.8%)).

Benefits favoured amitriptyline while harms were similar for both medications.