Lantus Insulin (aka Glargine)
Lantus/Glargine is human analog insulin that comes in U100 strength and requires the use of U100 syringes. Because it cannot be given any sooner than 10 hours after the last shot, it is the best insulin for those folks who are gone for extended hours during the day. Lantus is
not a good insulin to use for a cat with a history of ketones or DKA. It is sold in either 10ml vials, or 3ml cartridges (in 5 packs) that are designed for use with injection pens that are purchased separately. We recommend purchasing Lantus cartridges, but do not recommend buying the injection pens as it is impossible to measure part unit doses. Lantus cartridges look very much like "mini" vials, with a rubber stopper at the top. Purchasing cartridges will be more expensive at the outset (about $25-$30 more than a 10ml vial of Lantus) but there is much less waste compared to purchasing 10ml vials. Lantus expires approximately 28 days after opening, so it's likely that even a 3ml vial would not be empty by the time Lantus loses its potency. We recommend storing Lantus in the fridge. Depending on how it has been handled, we have found that Lantus can remain potent well past 28 days.
Lantus is clear, just like water. Should you ever see any crystals in the vial or cartridge, the Lantus has been damaged and should be discarded. If bubbles appear in Lantus, it will start to lose potency. Unlike when filling a syringe with PZI, it is recommended not to draw air into the syringe to express into the vial when measuring a Lantus dose, nor to back the insulin out of the syringe while it is still in the vial in an effort to avoid creating air bubbles. Draw more than your required Lantus dose into the syringe by at least a unit, remove the syringe from the vial and express the extra insulin onto a paper towel or tissue to avoid creating bubbles.
Lantus is available at any drug store as it is commonly used in humans. In some countries, like Canada for example, Lantus is available over the counter and does not require a prescription. If you are purchasing Lantus through your vet, you may wish to check pricing with your local pharmacy first in order to save yourself the extra cost of vet mark-up. Prices differ greatly – for example, premier drug stores charge $30 to $40 dollars more, where well-known stores such as Wal-Mart and Costco charge a lot less for Lantus.
When giving insulin shots, particularly with Lantus, you want to slowly push the plunger of the syringe in completely and with the syringe still inserted under the skin, slowly count to 10 before removing the needle from the injection site. You may have to hold your cat gently while you wait. Remove the syringe and very gently apply pressure for several seconds. DO NOT RUB THE AREA to avoid damage to the Lantus molecules.
Lantus is long lasting insulin, remaining in the system for 12 hours or more. It typically drops the BG slowly, has an extended nadir, and begins to slowly leave the system after approximately 8 to 10 hours. These are the norm, every cat is different. It is very important to maintain overlap on Lantus – meaning that the remnants of the prior shot are still working to keep the BG as close to normal range as possible, while the next shot is coming to onset.
Lantus is insulin that cannot be dosed any sooner than +10 hours after the last shot, and only to a rising BG over 150/8.3. It is imperative that your cat is curved on the first three or four shots when starting out, or when making even very minor dosing changes. The first curve starts with the preshot test, continues with testing every two hours afterwards to determine onset, nadir (peak insulin activity) and when the insulin starts to leave the system. The timing for tests on the second curve is dependent on the first curve’s results.
When using Lantus, rather than starting with a static dose every 12 hours as is typically prescribed, TR requires the use of a three rung sliding scale, with dosing at approximately every 10 hours as determined by the cat’s progress. When compared to PZI, a tighter dosing scale is used with Lantus and we find that the scale becomes almost "static" over time, with only very small adjustments made to doses. Eventually the Lantus scale is reduced to two rungs, and then possibly to one rung as the cat becomes better regulated.
Unfortunately there is a big challenge to using Lantus. It is released over time and does not result in the instant gratification that is seen with all of the other insulin types. In humans, Lantus crystals are still present in the system 24 to 48 hours after dose. In cats, due to their much faster metabolisms, Lantus lasts approximately half that time.
It takes approximately three shots of Lantus before you know if the dose is doing what it is supposed to do, such as reaching ideal numbers at nadir. If ideal BG is not reached after two to three doses, increases should be made by either "fat" increases or a maximum increase of 0.25u increments only.
Using Lantus requires PATIENCE