Leslie, Thanks so much for the reply. It's my husband that has the Sleep Apnoea.
Since I initially posed the question, he has been prescribed a variety of drugs, and the drug of choice currently is Tegratol. He has recently diagnosed with Nocturnal Epilespy, and it appears Gabapentin also acts as an anti-convulsant drug.
My husband had a lot of trouble with his initial mask when it was a small mask, he now has a full face mask and sleeps very well with it.
Funny though you should mention Lyrica, I suffer with CRPS, and initially Gabapentin did not work for me, but a combo of Lyrica and Tramadol helps somewhat.
Thanks again for taking the time to reply.