Table 2.

Combination therapy with pregabalin or gabapentin

Pregabalin/gabapentin combined with:	CDC rating of scientific evidence	RCTs testing the combination	Clinical practice experience concerning combinations
TCAs	I + A	Gilron et al¹⁰ and Holbech et al¹¹	Combination well documented. Most with peripheral NeP. Useful combination for patients who do not tolerate either drug in larger doses, as well as sedative effect from TCA to improve sleep disturbance
SNRIs	I/II + B/C	Tesfaye et al¹² and Tannenberg et al¹³	Combination reasonably well documented. Used by some of the experts with good effect and fewer side effects than with TCA
SSRIs	III + C	None	Insufficient evidence available. SSRIs not relevant in the treatment of NeP
Opioids^a	I + B	Gilron et al¹⁶, Hanna et al¹⁷ and Caraceni et al¹⁸	Good evidence to support combination therapy. Frequently used in daily clinical practice
Other antiepileptics^b (Na+ channel blockers)	C	None	Insufficient evidence available. Combination could work in theory due to different mechanisms of action. Limited clinical experience
Cutaneous patches	I + A/C	Casale et al,¹⁹ Meier et al²⁰ and Irving et al²¹	Mixed evidence and results for localized NeP. Patches add-on to oral therapy are used by some experts with good effect
Others	C	None	Insufficient evidence and clinical practice available

Notes:

Including synthetics.

Mainly sodium channel blockers, but also multiple mode of action drugs (valproic acid and topiramate).

Abbreviations: CDC, Centers for Disease Control and Prevention; NeP, neuropathic pain; RCTs, randomized controlled trials; SNRIs, serotonin-noradrenaline reuptake inhibitors; SSRIs, selective serotonin reuptake inhibitors; TCAs, tricyclic antidepressants.