Avoid taking Benzos as the poster above mentioned, since both opioids and Diazepam act on the central nervous system and there is a considerable risk.
I'd also skip the Lyrica as it potentiates (too much) opioids, I have also read that it could lead to Serotonin Syndrome when mixed with Oxycodone.
In regards to Fexofenadine, it is a third generation antihistamine which doesn't really act on the CNS even at higher doses. But I'd still avoid taking it.
I take Dihydrocodeine too and my rule of thumb is to NEVER mix anything with it, therefore no Benzos, alcohol, antihistamines, anti-epileptics etc...