Diabetes Talking

Question:

– Hide quoted text — Show quoted text – were wondering if it is possible for insulin to go bad. Is there any way Yes there is. Insulin should be kept cool ie in a fridge – but not frozen. Otherwise it loses its effectiveness. It is possible to keep it at room temperature for several weeks but it has to be discarded after this.                                      john b. .sig later For whatever it’s worth, I’m a type I who takes relatively little regular each day, like maybe 10 units.  This means my Regular bottle of 1000 units lasts me over 3 months.  I keep it with me all the time, in my backpack, and have never (for 28 years worth of diabetes) noticed a decrease  in activity over time.  That doesn’t mean there isn’t one, just that I haven’t ever noticed it. Dave (type I, 28 yers, 2 injections per day) — Dave Breeden

I also take small doses of Lente and regular insulin and I test regularly. I have been a diabetic for about 25 years and I rarely refridgerate my insulin. I have never found that the insulin looses its effectiveness. Allan — Allan Meltzer Ottawa, Ontario Canada K1N 7N8 613-565-3635

Response:

I have never found that the insulin looses its effectiveness. Ottawa, Ontario

Well, you *live* in a refrigerator, that’s why. Actually, I have noticed that regular insulin is far more susceptible to heat than lente or NPH.  (What does NPH stand for, anyway?)  Apparently, the Zinc has something to do with it.  Do doctor’s read this list?

Response:

(What does NPH stand for, anyway?)

NPH stands for Neutral Protamine Hagedorn, Hagedorn being the name of the Danish researcher who developed it, and protamine being one of the added ingredients. (Diabetes A to Z, Amer. Diabetes Assoc., pg. 50) Do doctor’s read this list?

Yes (I’m NOT one), but most prefer to lurk unless someone goes way off-base medically on a statement. And that’s ok with me, at least they’re involved. — God put me on Earth to accomplish a certain number of things. Right now, I am so far behind, I will never die.

Response:

I have never found that the insulin looses its effectiveness. Ottawa, Ontario Well, you *live* in a refrigerator, that’s why. Actually, I have noticed that regular insulin is far more susceptible to heat than lente or NPH.  (What does NPH stand for, anyway?)  Apparently,

NPH is the initials for Neutral Protamine Hagadorn (sp?), being a preparation of insulin complexed with the small basic peptide protamine.  Hagadorn was the pharmacist who developed and characterised the preparation.  The peptide protamine originates from trout and salmon testis, where it acts to condense the DNA to a workable size during spermatazoon maturation. the Zinc has something to do with it.  Do doctor’s read this list?

Zinc causes insulins to crystallize (by promoting the formation of hexamers, or is it octamers, from insulin monomers).  This process is used to extend the time course of insulin action, especially in the case of Ultralente (Ultratard) insulins where the crystals are visible as a sandy precipitate in the vial.  NPH (or protophane) relies on a combination of zinc and a peptide carrier to achieve similar ends.  I note that other proteins (globin for example) have also been used for this purpose, although I’m not aware that these preparations are now in common use. Peter A. Stockwell PS – in answer to your final question – I am a doctor, tho not a medical one – P.S.

Response:

Zinc causes insulins to crystallize (by promoting the formation of hexamers, or is it octamers, from insulin monomers).  This process is used to extend the time course of insulin action, especially in the case of Ultralente (Ultratard) insulins where the crystals are visible as a sandy precipitate in the vial.  NPH (or protophane) relies on a combination of zinc and a peptide carrier to achieve similar ends.  I note that other proteins (globin for example) have also been used for this purpose, although I’m not aware that these preparations are now in common use.

I thought that it was a ligand coordination reaction, not a crystalization. I could be misinformed.

Response:

Most adjustment problems result from changes in the individual, not changes in the insulin. Newly diagnosed patients usually change quite a bit over the first year or more, and constant adjustment is expected. *All* patients vary in their sensitivity to insulin over time periods on the order of days or weeks. All treatment plans should include procedures for adjusting basic dosages based on bG monitoring. Again, such changes are expected. Patients who have not been given such instructions may think their insulin has changed when it is their own sensitivity which has changed. However, if large changes occur while using a bottle, it is prudent to be very careful when starting the next, since a sudden increase in activity could cause hypoglycemia. The activity of commercial insulin preparations is not tightly controlled. At least, it wasn’t in the past — this may have changed with the advent of biosynthetic insulin. But it was never particularly important to get a high degree of consistency in the manufactured product because the natural variation of individual sensitivity over time buried the manufacturing variation. As others have pointed out, insulin can be damaged by heat or freezing. It does *not* have to be refrigerated and can be kept at room temperature for months without significant degradation. If monitoring and adjustment of dosage are set up properly, small changes in the insulin simply won’t matter, as they will be adjusted for automatically. Agitating most insulin preparations (as opposed to most patients) doesn’t damage the product. NPH insulins are the exception and should be kept from a lot of agitation, especially Humulin-N. Naturally occurring insulin is a hexamer. Monomeric insulin is being tested and may be marketed soon; it has faster action but is definitely a synthesized form. I don’t know the details of the chemical changes which cause the delayed action of protamine zinc and NPH insulins. —

Response:

were wondering if it is possible for insulin to go bad. Is there any way Yes there is. Insulin should be kept cool ie in a fridge – but not frozen. Otherwise it loses its effectiveness. It is possible to keep it at room temperature for several weeks but it has to be discarded after this.                                      john b. .sig later

For whatever it’s worth, I’m a type I who takes relatively little regular each day, like maybe 10 units.  This means my Regular bottle of 1000 units lasts me over 3 months.  I keep it with me all the time, in my backpack, and have never (for 28 years worth of diabetes) noticed a decrease  in activity over time.  That doesn’t mean there isn’t one, just that I haven’t ever noticed it. Dave (type I, 28 yers, 2 injections per day) — Dave Breeden

Response:

My sixteen year old son has type I diabetes, diagnosed earlier this year. He says that recently he is having trouble bringing his blood sugar level down, even with additional insulin. He may still be just adjusting, but we were wondering if it is possible for insulin to go bad. Is there any way to test this at home? He uses humulin (Lilly).

Response:

were wondering if it is possible for insulin to go bad. Is there any way

 Yes there is. Insulin should be kept cool ie in a fridge – but not frozen. Otherwise  it loses its effectiveness. It is possible to keep it at room temperature for several  weeks but it has to be discarded after this.                                       john b. .sig later

Response:

were wondering if it is possible for insulin to go bad. Is there any way Yes there is. Insulin should be kept cool ie in a fridge – but not frozen. Otherwise it loses its effectiveness. It is possible to keep it at room temperature for several weeks but it has to be discarded after this.

Users of insulin are also cautioned against excessive agitation (of the insulin, not the user ), which I have found by personal experience to be detremental to its effectiveness. The only way that I know of to "check" is to switch to another bottle and see if the numbers come down. If they do, I toss the old vial. That’s not definitive or scientific, but it’s enough to confirm any suspicions I may have. Better safe than sorry and all that. Now that I think about it, users of insulin are cautioned against excessive agitation of BOTH the insulin and the user. — God put me on Earth to accomplish a certain number of things. Right now, I am so far behind, I will never die.

Response: