Hi @Susan SS, Welcome to the forum.
Humulin insulins are based on regular human insulin. I think Humulin I is called NPH outside the UK. NPH is a 'cloudy' insulin with added zinc to give it a longer profile than regular human insulin, it is slower to start and longer to finish working.
It is 'peaky' and tends to have its peak action at 4-8 hours,and last 10-12 hours. Where as Levemir is supposed not to peak over its duration.
Often NPH is used to offer some meal coverage, as well as covering basal, and taken 2-3 times a day.
When changing from Levemir to NPH you will need to adjust the dosage and timing to suit the new profile.
It is. But it's unusual to change from a true basal insulin like Levemir to an intermediate acting NPH insulin.
A much more common change would be to Tresiba or Lantus.
Forewarned is forearmed and i'm grateful and its one of many reasons i love this site.
My concern is i might have to see a specialist or one of those DSN people who, and i haven't seen either of those for years, always tell me i'm doing it wrong...lol and i end up arguing, i try not to, and i always fall back with an " i've been at it most of my life never been hospitalised and i currently have a hba1c of 39 or 5.7" this irritates the life out of them and i end up being smug and pompous....and i'm getting worse as i get older.