My codeine tolerance - what's going on?

[curious_24]

I am a 200lb+ male who has been using codeine on a daily basis for around three years. I guess I am lucky in that even after all this time, my optimal dose for euphoria/contentedness is around 100mg and I can even feel doses as low as 25mg in a very subtle way. Recently I have begun to notice that my tolerance varies on a day to day basis. The other day I took around 100mg at 09;00 and had a good warm feeling going on. I then redosed around 19:00 with around the same amount and I thought I was about to OD! My heartbeat slowed, I got very tired and dizzy and had absolutely no euphoria. This feeling slowly wore off after about two and a half hours and is exactly the same feeling as I remember when I first tries upping my dose to around 150mg from my then standard of 75mg.

Two questions I have -

1. Why can I still enjoy such low doses after years of daily abuse?
2. How can 100mg be perfect one day, not enough the next then too much the day after?

As a side note, I am using pure UK manufactured codeine phosphate pills so no complications from CWE or similar.

Please forgive any typos - posted on my phone

 

[NeighborhoodThreat]

1. You're lucky, that's for sure. Different people metabolize codeine differently, sounds to me like you're just one one of the people who gets more out of codeine.

2. I'm not exactly sure, but it may have something to do with your metabolism. Are you taking any other drugs or supplements? Many things interact with codeine metabolism...but it is hard to be 100% sure.