The tricyclic antidepressants prevent the reuptake of monoamines, including serotonin and noradrenaline, as both pathways are important in the pain propagation. So the mixed reuptake drugs work better than more selective drugs like SSRIs
But serotonin-noradrenaline reuptake inhibitor antidepressants (SNRIs), for example, venlafaxine & duloxetine and the atypical antidepressant group, such as bupropion and mirtazapine are also effective for some chronic pain conditions and are increasingly used because of their improved tolerability
The superiority of tricyclics, particularly clomipramine and amitriptyline, in the management of pain may also be explained by their additional action on sodium channels blockade ( which is an action that SNRIs do not exhibit.)
The dose of amitriptyline to treat pain is much lower when compared to that needed to treat depression
The analgesic action has a faster onset, whereas antidepressant action takes weeks to start
The sedative action of tricyclic antidepressants are helpful in treating the sleep disturbances associated with neuropathic syndromes. Nortriptyline is less sedative than amitriptyline.
#antidepressants , #analgesics , #PainManagement , #ChronicPain
Reference: Medscape, Pharmacogenetics and Analgesic Effects of Antidepressants in Chronic Pain Management, Frédérique Rodieux; Valérie Piguet; Patricia Berney; Jules Desmeules; Marie Besson, Personalized Medicine. 2015;12(2):163-175.
Ryder S A, Stannard C F. Treatment of chronic pain: antidepressant, antiepileptic and antiarrhythmic drugs. Contin Educ Anaesth Crit Care Pain 2005; 5: 18–20 .