Anticonvulsant conversions

[NJPAIN]

I have a satisfactory method to transition from Neurontin to Lyrica and visa versa from the psychiatry literature. However, I do not have a satisfactory way to transition from either Neurontin or Lyrica to other anticonvulsants such as Lamictal, Trileptal, etc. While an option is certainly discontinuing one prior to starting another that is obviously suboptimal in a patient with severe, poorly controlled neuropathic pain. Anyone willing to share their way to gradually transition or directly convert from one to another??

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[lobelsteve]

If a drug doesnt work i stop it. Start new one at lowest dose and titrate. Anticonvulsant is an antiquated term as the drugs have varied MOA.

 

[NJPAIN]

Steve - thank you for you input on this issue with regard to MEMBRANE STABILIZING AGENTS.

 

[clubdeac]

I don't know the right answer but you could taper down half way and then start titrating the other med up. Taper off previous med once you reach full dose of second med.

 

[bedrock]

I would taper halfway down, then start the other when transitioning from gabapentin to lyrica (as deac described).

However it using a different class of membrane stabilizers, I would try both medications together (just start the second one as long as there was a partial benefit to the first one). Some patients do better on two different membrane stabilizers at the same time.

 

[pastafan]

I would taper halfway down, then start the other when transitioning from gabapentin to lyrica (as deac described).

However it using a different class of membrane stabilizers, I would try both medications together (just start the second one as long as there was a partial benefit to the first one). Some patients do better on two different membrane stabilizers at the same time.

Different drugs acting on different receptors do appear to work well together. If adding second drug provides relief at low doses then I will try to wean first drug and maximize dose of second medication. Less cost, side effects, and greater compliance with fewer drugs to take.

 

[Aether2000]

I suppose I do it a bit differently. I don't taper these classes of drugs unless the patient has a seizure disorder. I simply stop one (eg. gabapentin) and convert directly to another drug. These drugs are generally not significantly metabolized, passing through the kidneys virtually unchanged, therefore all have very short elimination half lives. My simplistic conversion ratio is approximately gabapentin: pregabalin is 5:1

 

[Ducttape]

If a drug doesnt work i stop it. Start new one at lowest dose and titrate. Anticonvulsant is an antiquated term as the drugs have varied MOA.

what, you dont call them Voltage-gated α2δ calcium channel blockers (for gabapentin and lyrica) ?

 

[BobBarker]

you guys really have much luck with these things?

 

[NJPAIN]

I suppose I do it a bit differently. I don't taper these classes of drugs unless the patient has a seizure disorder. I simply stop one (eg. gabapentin) and convert directly to another drug. These drugs are generally not significantly metabolized, passing through the kidneys virtually unchanged, therefore all have very short elimination half lives. My simplistic conversion ratio is approximately gabapentin: pregabalin is 5:1

How about going from Neurontin or Lyrica to Lamictal or Trileptal?
( I know, I should not be using brand names, shame on me)

 

[lobelsteve]

Same as Algos. No tapers. Lyrica starts at 75mg bid unless elderly or renal impaired. Double it every 3 days until effect, side effect, or 600mg and no effect.
Keppra 500mg bid if not better than 1000mg bid, then stop if no better.
Pamelor 10mg tid (unless elderly then just QHS), can go to 25mg tid. (TCA and not AED)
Lamictal rarely use.
Trileptal 150 bid, as high as 300 bid
Tegretol 200 bid, as high as 600mg bid.

 

[clubdeac]

Same as Algos. No tapers. Lyrica starts at 75mg bid unless elderly or renal impaired. Double it every 3 days until effect, side effect, or 600mg and no effect.
Keppra 500mg bid if not better than 1000mg bid, then stop if no better.
Pamelor 10mg tid (unless elderly then just QHS), can go to 25mg tid. (TCA and not AED)
Lamictal rarely use.
Trileptal 150 bid, as high as 300 bid
Tegretol 200 bid, as high as 600mg bid.

Interesting pamelor dosing... I give all mine at night. I would think you'd see a lot of daytime drowsiness and less compliance with tid dosing. You got data?

 

[Papa Lou]

you guys really have much luck with these things?

YES! I rely on them for a lot of pts and get decent results. nnt like 4-6

 

[Papa Lou]

Same as Algos. No tapers. Lyrica starts at 75mg bid unless elderly or renal impaired. Double it every 3 days until effect, side effect, or 600mg and no effect.
Keppra 500mg bid if not better than 1000mg bid, then stop if no better.
Pamelor 10mg tid (unless elderly then just QHS), can go to 25mg tid. (TCA and not AED)
Lamictal rarely use.
Trileptal 150 bid, as high as 300 bid
Tegretol 200 bid, as high as 600mg bid.

omg. if gaba and lyrica dont do it I move to snri. too many good options there to go with stuff like lamictal, trileptal, tegretol, keppra i think

 

[lobelsteve]

Interesting pamelor dosing... I give all mine at night. I would think you'd see a lot of daytime drowsiness and less compliance with tid dosing. You got data?

Extrapolated from average effective dose of elavil at 105mg. From Dannemiller lecture, likely dr. Abrams.

 

[Aether2000]

The only Cochrane evidence is for Tegretol, Lyrica, and Neurontin.

 

[lobelsteve]

omg. if gaba and lyrica dont do it I move to snri. too many good options there to go with stuff like lamictal, trileptal, tegretol, keppra i think

I see a lot of TN, so I use tegretol or trileptal or aptiom as well as baclofen.
For neuropathy outside head and neck: Lyrica, Cymbalta, Pamelor, Elavil, Doxepin, Keppra, Gabapentin. Rarely anything else.

 

[melancholy]

if no side effects but just not helping with original neuropathic agent, i will generally start the new one and leave all other factors the same and then depending on initial titration of new med, then taper off the old one. some patients do fine with cold turkey'ing neuropathic agents and others don't, but if they have some leftover, why not just do some sort of taper (fast or slow) b/c you have all the time in the world.

occasionally, i find that someone is on a neuropathic agent which does help, but they don't realize it until they start tapering off and their symptoms worsen. that is why i try to keep other factors the same as much as possible while adjusting a single agent at a time. it takes awhile, but is easier when patients haev all sorts of odd symptoms and responses to these things.

neurontin (w consideration to switch to lyrica only if neurontin helps, but get diminishing returns at higher dosages), keppra or topamax, trileptal, tegretol. haven't had to trial lamictal much.
nortriptyline, doxepin or desipramine, effexor or cymbalta...

 

[clubdeac]

Extrapolated from average effective dose of elavil at 105mg. From Dannemiller lecture, likely dr. Abrams.

Did you mean 10mg or 105mg?

 

[lobelsteve]

Did you mean 10mg or 105mg?

105mg avg dose.

 

[Papa Lou]

I see a lot of TN, so I use tegretol or trileptal or aptiom as well as baclofen.
For neuropathy outside head and neck: Lyrica, Cymbalta, Pamelor, Elavil, Doxepin, Keppra, Gabapentin. Rarely anything else.

Yes I saw your video for intranasal lidocaine TN tx. Why not sphenopalatine block then maybe RFA it? That works well. If that doesn't do it then subacromial decompression which has great results or gasserian ganglion block which also has great results. Just curious...I don't see that many of them.

 

[lobelsteve]

Yes I saw your video for intranasal lidocaine TN tx. Why not sphenopalatine block then maybe RFA it? That works well. If that doesn't do it then subacromial decompression which has great results or gasserian ganglion block which also has great results. Just curious...I don't see that many of them.

The intranasal is an SPG. If it fails after meds I do gasserian RFA. MVD only works with defined pathology on MRI, and those folks never make it to a pain clinic.

 

[Aether2000]

My problem with tapering one anticonvulsant while starting another of unknown equivalency is that the patient may actually experience the same issues that they do when converting from one opioid to another. I have never seen a person have any problems dead stopping one and converting directly to another especially given the very short half life. But what works in my hands may not work in anothers and vice versa....the art of medicine

 

[clubdeac]

Yes I saw your video for intranasal lidocaine TN tx. Why not sphenopalatine block then maybe RFA it? That works well. If that doesn't do it then subacromial decompression which has great results or gasserian ganglion block which also has great results. Just curious...I don't see that many of them.

I'm surprised that a subacromial decompression works for TGN? hehe

 

[Papa Lou]

The intranasal is an SPG. If it fails after meds I do gasserian RFA. MVD only works with defined pathology on MRI, and those folks never make it to a pain clinic.

Yeah I mean SPG block with a needle, then RFA it if it responds. Then intranasal video I was referring to was lidocaine injected into nasal cavity which I don't think is quite as good. But it's not important. What I really am curious about now is whether you're saying YOU personally do gasserian RFA? That is a hardcore procedure.

 

[lobelsteve]

Yeah I mean SPG block with a needle, then RFA it if it responds. Then intranasal video I was referring to was lidocaine injected into nasal cavity which I don't think is quite as good. But it's not important. What I really am curious about now is whether you're saying YOU personally do gasserian RFA? That is a hardcore procedure.

A couple per year. No biggie. Just got to be my own fluoro tech to get the picture right.

 

[EtherBunny]

Yes I saw your video for intranasal lidocaine TN tx. Why not sphenopalatine block then maybe RFA it? That works well. If that doesn't do it then subacromial decompression which has great results or gasserian ganglion block which also has great results. Just curious...I don't see that many of them.

Yeah, the microvascular decompression surgery is a mixed bag in terms of outcomes. Yes, the patients need findings on MRA that are consistent with vascular compression of CN V. But I've seen some pretty bad results from these cases, not only when I was in neurosurgery but also when I was a pain medicine fellow.

Regarding the anticonvulsant conversions, I don't utilize any conversion ratios. I generally recommend a quick downward titration of the previous agent. Concurrently I introduce the new agent.

On a related note, am I the only one on this forum that finds the variability in practice patterns disturbing? By this I don't mean that people on here are committing malpractice, or anything like that. But don't you find it a bit alarming that even fundamental activities, like converting a or from one anticonvulsant to another, aren't completely standardized? Shouldn't this be a uniform practice, such that every fellowship trained pain doctor does it the same way? Why is our field like this? Can we change it? Should it be standardized?

It seems like anytime a clinical question is asked on this forum, there are ten different answers. So much variability.

Just some food for thought...

 

[Ducttape]

Its called the Art of Medicine. More than one (appropriate) way to skin a cat.

Surgeons argue incessantly about the correct approaches to their cases. Internists, while they have first line/second line drugs for Htn, DM type 2, hyperchol, also have very idiosyncratic and personalized prescription patterns. So do we.

 

[EtherBunny]

Its called the Art of Medicine. More than one (appropriate) way to skin a cat.

Surgeons argue incessantly about the correct approaches to their cases. Internists, while they have first line/second line drugs for Htn, DM type 2, hyperchol, also have very idiosyncratic and personalized prescription patterns. So do we.

True, but sometimes I worry that pain medicine has too much "art" and not enough science to back up our clinical decisionmaking, which can explain high variability in practice patterns. I readily acknowledge that there will always be an artful component to medicine and some variability is to be expected, but ultimately all of our medical decisionmaking should be squarely grounded in science. Right now I just don't know if pain medicine as a field is more art than science, or the other way around.

 

[Ducttape]

the problem is that pain is so subjective, unlike a "hot appendix" that leads to almost no debate on clinical diagnosis.

 

[bedrock]

the problem is that pain is so subjective, unlike a "hot appendix" that leads to almost no debate on clinical diagnosis.

Diagnosis of appendix is universal, however plenty of debate on treatment.

There was a large British study in the past 18 months that demonstrated that over two-thirds of appendicitis cases can be treated with abx and close monitoring and that the reflex response to just remove all of them surgically , is outdated and unnecessary.

 

[Papa Lou]

True, but sometimes I worry that pain medicine has too much "art" and not enough science to back up our clinical decisionmaking, which can explain high variability in practice patterns. I readily acknowledge that there will always be an artful component to medicine and some variability is to be expected, but ultimately all of our medical decisionmaking should be squarely grounded in science. Right now I just don't know if pain medicine as a field is more art than science, or the other way around.

It'll be years before that happens. The field IS more art than science at this point--but it's growing fast. I'm glad it's not cookbook. If it were, then an NP or PA or robot could make the changes. The decision making processes outlines by Bogduk in managing chronic low back pain, if you are one to follow the algorithm, is very cookbook. Again something a robot could do and an "injectionist" is all that's then needed. The point IMO is to arrive at correct diagnosis as fast as possible. And for this it's all too patient and practitioner dependent. I'm happy about it...helps you stand out if you try hard, unlike following recipes.

 

[bedrock]

you guys really have much luck with these things?

Agree with papa lou, my NNT is about 4. They help a lot of people but switching classes is important in my mind if they don't respond to the first one. Can't just use gabapentin and then give up. I do use lots of gabapentin/lyrica like everyone else, but will use elavil QHS if they fail those or if insomnia or headache are major components of their pain. Agree that SNRI can be quite useful, but I tend to add that if they are other things to treat besides nerve pain. I use topamax as a fourth line agent sometimes, or earlier if they are also a chronic headache sufferer, particularly migraines, (also if they could lose a few pounds). Just mentioning weight loss makes for 100% patient compliance with topamax. Will use trileptal as last resort if they fail everything else.

I have had a number of patients with major chronic discogenic pain (without radiculopathy) who responded quite well to gabapentin. The NNT is high, probably 20-25, but I've gotten people off opioids with this, or prevented the need for them. Many patients who respond to gabapentin for this, tend to do particularly well with long-acting gabapentin formulations such as Gralise.