I Havent Taken Lamotrigine for a Month but Want to Start Again What Should I Do

• #1

A patient of mine reportedly stopped taking her medications three days ago, one of which was Lamictal 100 mg nightly. In residency I was taught that if a patient skips their Lamictal dose for 3 consecutive days, yous need to start back over at 25 mg per day upon resuming, to minimize the hazard of SJS. I don't know if that was only my attending'southward opinion at that time, or if there is annihilation prove-based behind it. Anyone know what the risk would exist with resuming 100 mg right abroad, or chop-chop titrating the dose support? Or would it be best to do the 25 mg for ii weeks, then 50 for two weeks, etc.?

• #3

At that place'southward no clinical data from studies every bit far every bit I know showing how long the duration should be when nosotros should tell patients to restart Lamotrigine past going back to the starting dosages.

From my own clinical experience if patients forgot to accept a loftier dosage by just a scattering of days at that place never was a trouble.

From my educated judge I suspect the period where run a risk of SJS goes upwardly from not taking it would probable exist at least a few weeks based on the mechanism probable being involved with the immune system. Serum Ig one-half life is about 3 weeks, merely this is based on theorize that's not based on empirical data.

• #four

The incidence of SJS with Lamictal without a tiresome titration is very small, so any one doctor's individual experience won't be powered well enough to notice the difference between when to restart at 25mg and when to restart at whatsoever dose the patient was at.

And then when in doubt, I'd look at what semi-formal guidelines may be. UpToDate says to start at the commencement if missed for more than 5 half-lives, and to start low and still gradually get back to where you were if missed for fewer than 5 half-lives.

• #five

I was besides taught 3 days in residency, but half of what residents are taught is folklore, then it's adept to get in the habit of looking things upward on your ain.

GlaxoSmithKline product sheet recommends restarting information technology after 5 half-lives. Average half-life is virtually 26 hours, so roughly 5 days.

I would use the one-half-life to get a crude thought where they might exist when deciding what dose to restart at for <5d.

• #half-dozen

No board will give me blessing to test when the run a risk significantly elevates to crusade SJS.

The real outcome to consider is liability. Lamictal has been shown to cause SJS with quick titrations. No way I'm taking whatsoever chances in a courtroom room. Greater than 2 days off Lamictal and I'm restarting information technology. I document such and ever warn of restarting it upon initial consent.

• #7

Our policy in residency is too 3 days or greater and we retitrate.

• #8

If 5 days is sorta the outside based on the math of ane/2 lives, then iii days just sorta jives with me as a moderate point for the tip betwixt restart vs resume. Pushing information technology to closer to v, the outside, won't audio as good in courtroom. Non that anything bad e'er sounds good in court, just iii > v.

• #ix

I had a patient exercise a restart themselves later on probably like five days. They were covered in rash. They continued taking information technology, and they were OK. But I would not accept wanted to be responsible for any of that at all.

• #10

UpToDate says to offset at the beginning if missed for more than 5 one-half-lives, and to get-go low and still gradually go back to where you were if missed for fewer than v half-lives.

Finally! Some source giving a guideline. It was in Uptodate simply what was the original source?

• #11

Finally! Some source giving a guideline. It was in Uptodate but what was the original source?

As I mentioned earlier, the product monograph peradventure? Theyre compiled by the drug company and canonical by the FDA.

• #12

I don't claim there'south information to my side by side thoughts. But it wouldn't be terribly difficult to come with the pharmacokinetics to look at what the predicted AUC is at a dose, and what it is going backward on the titration schedule to what the dose would be at that place, and it's AUC, and then utilize the one-half-lives to calculate when one would drop below that. Although, it raises a business organisation because I read somewhere that sharp cessation of lamotrigine can besides be dangerous. Then you lot might think yous could figure out where someone is at later on yet many days, and restart at that lower dose (merely not the very beginning at 25 mg) and and so work upwardly. I get that this is a thought experiment and likely not as straightforward to practice.

This sounds to me like an interesting chat to have with a knowledgeable pharmacist.

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Source: https://forums.studentdoctor.net/threads/restarting-lamictal-after-skipping-for-a-few-days-when-do-you-start-over-at-25-mg.1345200/

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