You don't want to take diphenhydramine because it inhibits action of the enzyme 2D6. Dhc is a prodrug for dihydromorphine , or in other words, dhc must be metabolized into dihydrmorphine by the enzyme 2D6 for euphoria and pain killing effects . If 2D6 is inhibited, dhc will seem weaker than usual
Second there is a difference between synergy and potentiation . For example, Diazepam synergizes well with dhc because it doesnr increase the amount of dhc absorbed or metabolized, but rather it adds cns depression, muscle relaxation, and anxiolytic properties combine well with dhc pain killings effects and dopamine release in the cns. On the other hand, white grapefruit juice would be a potentiate dhc by indirectly increasing the amount of dihydrmorphine that can bind to mu opiate receptors . Eating a raw grapefruit contains the most amount of alkaloids that are moderately strong at inhibiting 3A4 which is the enzyme that converts dhc into inactive metabolites which will be flushed out of your body. By blocking 3A4 , dhc has s strong probability of being metabolized into dihydromorphine by 2D6 instead of inactive shit by 3A4
Gabapentin is an synergizes exceptionally well with opiates. I would definitely add some in, neurontin will increase analgesia from dhc, and it will make your diaZepam feel stronger. Good thing is that gabapentin causes minimal cns depression and almost extremely impossible to od on if you have a toleranc
I also recommend smokn weed, but only if you are a regular smoker. Marijuana creates the best synergy with opiates and almost every drug IMO
Make sure you exercise if your condition allows for light exercise. Exercise is the best natural painkiller; like 15 mins of walking around the block, or s bike ride, or tennis, ect..sometging not so intense but will still get your heart rate up