Harm Reduction Diazepam increases codeine half-life by 1.5 times? Confused 🤔

[mauve]

Hi guys! I've been of Morphine for a week now.

I bought some co codamol to take as needed as my back pain is horrendous sometimes.

I'm currently taking 40mg diazepam a day.

I know codeine lasts about 4-6hrs
Has a half life of 3hrs~
So by 15hrs it's cleared my system

However reading this article

[Pilot study of the metabolism of codeine to morphine and a possible modification by benzodiazepines] - PubMed

After administration of high-dose codeine we found that in two cases 20-40% of the total morphine-equivalents in the 24-hour urine sample were free morphine. After another 24 hours the proportion of free morphine was up to 70% and after roughly 96 hours even went up to 96%. Although 10% of the...

pubmed.ncbi.nlm.nih.gov

"The short half-life of codeine in serum was 2-4 hours, the final half-life was 9-11 hours. In urine we found a short half-life of 1-6 hours as well as a long half-life of 7-12 hours. When diazepam was administered simultaneously with codeine the expected half-life in serum was up to 1.5 times and in urine 2.5 times."


Am I correct that it says diazepam taken simultaneously with codeine increases the half life of codeine by 1.5 times this increasing the time taken to clear the system by the same amount

So does that mean instead of the average 15hrs codeine being cleared when taken alone if taken with diazepam would increase it to 37.5hrs? If it increases it by 1.5 times

Or am I missing something?

Thank you in advance!

 

[Xorkoth]

Increasing by 1.5 times means adding 50%. Increasing by 1 times means it's the same (something N x 1 = N). So if that study is correct, it means it would make it go from 15 hours to 22.5 hours.

 

[mauve]

Increasing by 1.5 times means adding 50%. Increasing by 1 times means it's the same (something N x 1 = N). So if that study is correct, it means it would make it go from 15 hours to 22.5 hours.

Thank you so much! Got it now