As an add-on to treat partial epileptic seizures in adults and children. (IR Neurontin only)
Postherpetic neuralgia (AKA herpes zoster, AKA shingles, AKA the reason why parents shouldn’t buy into anti-vaccination paranoia and take their children to chicken pox parties). (Both IR Neurontin and ER Horizant)
What isn’t Neurontin used for? Sometimes Neurontin is a valid therapy for the following, and sometimes it is utter quakery and placebo. There was one big-ass settlement against Parke-Davis (acquired by Warner Lambert, acquire by Pfizer) for their pushing Neurontin on doctors for inappropriate uses. So remember to check on who paid for the studies in question, as it will tends to make the results more favorable for the company paying for it (on average 3.6 times more likely, according to a Yale study).
These are just some of the off-label uses of Neurontin we’re aware of. Let’s start with some that it’s actually good for:
Restless Leg Syndrome/PLMD - Note the new extended-release form under the name Horizant has FDA approval to treat RLS, but it is still an off-label application for classic immediate-release Neurontin (gabapentin).
And where it’s a placebo with side effects, albeit a fairly low side effect profile for an AED:
Migraines (although it does work for other types of headaches now and then)
MS (It tests a little better than placebo, putting it in last-straw territory)
Chronic Fatigue. But what isn’t used for chronic fatigue?
And probably a bunch of stuff I don’t even know about. Maybe it’s quite useful in these applications, sometimes it’s prescribed first just because it’s an AED/anticonvulsant with a very low side effect profile and doctors are sick and tired of people whining about both their vague symptoms and how medication-sensitive they are.
When & If Neurontin Will Work
Neurontin’s Usual Onset of Action (when it starts working)
It should start to do something for you a couple days after you reach 900mg a day. But because of the whole bioavailability issue it may not be until you’re somewhere in the range of 900–1800mg a day, presuming it will do anything at all for you.
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Likelihood of Working
Postherpetic Neuralgia, Neuropathy and Neuropathic Pain
Neurontin, and its cousin Lyrica, are better pain meds than they are AEDs. Neurontin is actually a pretty good med when it comes to shingles and other incredibly painful conditions. If your pain is caused by your nerves and not by inflammation or something else that isn’t obvious, the odds are somewhere in the 2 out of 3 to 3 out of 4 range that Neurontin will have some positive effect. It may or may not be enough, but if it does something more than give you the stupids, at least you and your doctor will have a good idea that your pain is neuropathic in origin. So if you weren’t sure of its origin, that’s a hell of a lot better than nothing.
Neurontin is a decent med for the types of anxiety that respond to benzodiazepines, such as GAD, panic disorders, and agoraphobia. It’s usually not much of a help for OCD. If long-term and/or daily use of a benzo isn’t an option, using Neurontin instead might be worth a shot.
Does anybody still take Neurontin for epilepsy? I haven’t been able to find much in the way of reports from the field that are from this century.
Restless Leg Syndrome
Extended-release Horizant (It lets you remain horizontal? What if you like sleeping in an easy chair?) is too new, and as an off-label application for the classic immediate-release flavor the results were so-so. When Mouse took Neurontin for pain and anxiety - OK for pain, marginally better than anything else for anxiety - it made her RLS so much worse I had to sleep on the couch. She could sleep through it. I have no idea when or if I’ll get back to you with real data on how well it works.
Given all the different things for which Neurontin is used, I’m not about to cover all the possible dosages. I’m just going to cover the FDA-approved applications in adults. For everything else it’s between you and your doctor. Even with the approved stuff it’s going to be between you and your doctor, because I’m more or less OK with the party line. The only real problem I have with the recommendations from the PI sheets is the same problem I have with most meds: target dosages. Other than remaining at the dosage where your symptoms stop and raising it only when you need to, I’m good with everything else.
In adults with postherpetic neuralgia, Neurontin therapy may be initiated as a single 300-mg dose on Day 1, 600 mg/day on Day 2 (divided BID), and 900 mg/day on Day 3 (divided TID). The dose can subsequently be titrated up as needed for pain relief to a daily dose of 1800 mg (divided TID). In clinical studies, efficacy was demonstrated over a range of doses from 1800 mg/day to 3600 mg/day with comparable effects across the dose range. Additional benefit of using doses greater than 1800 mg/day was not demonstrated. —Neurontin PI sheet
Depending on how much pain you’re in, the rate the dosage is increased (titration) in Pfizer’s recommendation is too fast, too slow, or just right. As with any crazy med, you should stop increasing your dosage when your symptoms stop, and remain at that dosage until you need to raise it. So if Neurontin works for you at 600mg a day, then stay there.
See Interesting Stuff for why dosages of 1800mg a day for anything are a waste of money and side effects.
The recommended dosage of HORIZANT is 600 mg twice daily. HORIZANT should be initiated at a dose of 600 mg in the morning for 3 days of therapy, then increased to 600 mg twice daily (1,200 mg/day) on day four. In the 12-week principal efficacy study, additional benefit of using doses greater than 1,200 mg a day was not demonstrated, and these higher doses resulted in an increase in adverse reactions. If the dose is not taken at the recommended time, skip this dose, and the next dose should be taken at the time of the next scheduled dose. —Horizant PI sheet
The folks at XenoPort are a bit more in tune with the concept of gradual titration. They make a 300mg tablet, so you have even more options. As with IR Neurontin, it all depends on how much it hurts.
The effective dose of Neurontin is 900 to 1800 mg/day and given in divided doses (three times a day) using 300 or 400 mg capsules, or 600 or 800 mg tablets. The starting dose is 300 mg three times a day. If necessary, the dose may be increased using 300 or 400 mg capsules, or 600 or 800 mg tablets three times a day up to 1800 mg/day. Dosages up to 2400 mg/day have been well tolerated in long-term clinical studies. Doses of 3600 mg/day have also been administered to a small number of patients for a relatively short duration, and have been well tolerated. The maximum time between doses in the TID schedule should not exceed 12 hours. —Neurontin PI sheet
Yeah, sure. Who takes Neurontin for epilepsy any more?
The recommended dosage for HORIZANT is 600 mg once daily at about 5 PM. A daily dose of 1,200 mg provided no additional benefit compared with the 600-mg dose, but caused an
increase in adverse reactions. If the dose is not taken at the recommended time, the next dose should be taken the following day as prescribed. —Horizant PI sheet
I can’t think of another med with a specific time of day to take it. I need to dig into the PK, clinical trials, and assorted other data to figure out what the hell that’s about. The first thing I think of, though, is it’s something like Aplenzin’s dosages (scroll way down).
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How to Stop Taking Neurontin (discontinuation / withdrawal)
Because Neurontin is an AED I used to be as paranoid about it as other AEDs. Now I think you should only worry about discontinuing too quickly if you’re epileptic or have other seizure risk factors (recently stopped drinking heavily, have an anorectic eating disorder, etc.), and you are taking a pro-convulsant like lithium, Wellbutrin, or a stimulant, and/or your are not taking another AED. Simple, right? In any event, reducing your dosage by 600mg each week (as Pfizer and XenoPort recommend) or 300mg every 3 to 4 days (as I suggest) is unlikely to give most people any problems.
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Neurontin’s Pros and Cons
It has a very low side effect profile.
Few drug-drug interactions. Neurontin (gabapentin) is a proven pain reliever that doesn’t mess with you as much as the other anticonvulsants do, and works better for non-migraine pain better than most of the others.
It doesn’t work for a lot of people, mostly because of bioavailability issues. Because of Parke-Davis’ allegedly sleazy marketing practices you probably can’t get samples from your doctor anymore.
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Stick to your AED-based treatment plan. Buttons and magnets, 2.25″ $4 & 3.5″ $4.50 the each
Interesting Stuff your Doctor Probably didn’t Tell You about Neurontin
The interesting thing doctors and pharmacists should never skip is you can’t exchange Neurontin and Horizant at a 1:1 ratio. I don’t think I’ll be able to figure out a schedule. Why? This is why:
As dose is increased, bioavailability decreases. Bioavailability of gabapentin is approximately 60%, 47%, 34%, 33%, and 27% following 900, 1200, 2400, 3600, and 4800 mg/day given in 3 divided doses, respectively. —Neurontin PI sheet
You can try to squeeze out a little more absorption by taking it with food, but you buy a whopping 14% increase, on average, in the bioavailability. Sometimes every little bit helps.
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No matter which neurological and/or psychiatric drug you take, you’ll probably get one or more of these side effects. These will usually be gone, or at least will diminish to the point where you barely notice it most of the time, within a week or two.
Drowsiness / fatigue - even when taking stimulants in some circumstances.
Insomnia, instead of or alternating with the drowsiness.
Assorted other minor GI complaints (constipation, diarrhea, etc.)
Generally feeling spacey / out of it
Which can all add up to the ever-helpful “flu-like symptoms” listed as an adverse event on the PI sheet of practically every medication on the planet used to treat almost any condition humans and other animals could have.1
All crazy meds can, and probably will affect your dreams as well. There is no way of telling if that will be good or bad, let alone if this side effect is permanent or temporary.
Any of the above side effects you see listed again below means they’re even more likely to happen and/or stick around longer and/or are worse than most other meds.
Typical Potential Side Effects
The usual for Antiepileptic drugs, albeit to a lesser degree for most people. Although at the higher dosages Mouse and I, especially Mouse, experienced memory problems. The main problems with Neurontin are dizziness, cloudy thinking, fatigue and klutziness.
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Uncommon Potential Side Effects
Edema. Really goofy thinking - hence the nickname “Morontin.” If being treated for bipolar disorder, don’t be surprised if it results in hypomania instead of working as a mood stabilizer - as that has been reported in the clinical trials for epilepsy, in at least one of the studies on Neurontin (gabapentin) as a treatment for bipolar, and several times in the online support groups.
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Freaky Rare Side Effects
Taste perversion, abnormal accommodation, libido increased, baby you are coming over to my house right now! I’ve got plenty of Neurontin on hand!
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Don’t worry about actually buying one. Windows shop and share the designs you’d like to buy. Do you have something better to do right now?
What You Really Need to be Careful About
Operating heavy machinery. Really. Impaired thinking and loss of coordination are potential side effects that sometimes don’t go away, so you may not be able to drive a car or a Zamboni while taking Neurontin.
Neurontin’s Half-Life & How Long Until It Clears Your System
Plasma half-life: Half-life: 5–7 hours. It’s out of your system in 2 days.
Half-life is the average time it takes for you to process half of the drug’s active ingredient. If a drug has a half-life of around 24 hours and you take a dose of 100mg, you’ll have roughly the equivalent a 50mg dose after one day, a 25mg dose after two days, and so on. The rule of thumb is: multiply the half-life by five and you get how long it is for the dose you took to be cleared from your bloodstream2, so there’s nothing swimming around to attach itself to your brain and start doing stuff. That’s called “plasma clearance.” Complete clearance is a complex equation based on a lot of factors which may or may not: be published in the PI sheet, include personal data like your weight, or even completely figured out by corporate and independent researchers. It usually winds up being 2–5 days after plasma clearance no matter what3, but can take weeks. Sometimes a drug will clear from your brain and other organs before it clears from your blood.
Steady state is reached in: 2 days after you’re taking however much you take 3-times-a-day (TID)
Steady state is the flipside of half-life. This is when you can expect to get over side effects caused by fluctuating amounts of a medication in your bloodstream. Often, but not always the same amount of time as the plasma clearance above.
Hah! That’s like asking the half-life of Lamictal or the taxonomy of the Leratiomyces ceres. While the Mechanism of Action/Pharmacodynamics section of the PI sheet for every drug on the planet is predicated with some variant of “We have no freaking clue of how it works. We’re pretty sure what it doesn’t do. So our best guess is…” Parke-Davis doesn’t even bother with the guesswork. We get a whole bunch of clues from the PI sheet that map how everyone thought it worked at one time or another:
Gabapentin is structurally related to the neurotransmitterGABA (gamma-aminobutyric acid) but it does not modify GABAA or GABAB radioligand binding, it is not converted metabolically into GABA or a GABAagonist, and it is not an inhibitor of GABA uptake or degradation.
In vitro studies with radiolabeled gabapentin have revealed a gabapentin binding site in areas of rat brain including neocortex and hippocampus. A high-affinity binding protein in animal brain tissue has been identified as an auxiliary subunit of voltage-activated calcium channels. However, functional correlates of gabapentin binding, if any, remain to be elucidated. —Neurontin PI sheet
Stahl elucidates the current consensus on how Neurontin (gabapentin) and Lyrica (pregablin) work:
The active ingredient is usually the same as the generic name, but more often than not it’s a chemical salt of the substance identified as the generic. E.g. Fluoxetine is the generic for Prozac, but the active ingredient is fluoxetine hydrochloride (or HCl). It usually doesn’t make much of a difference outside of the more esoteric aspects of a drug’s pharmacology, but not always.
Morphine and hydrocodone. They’re weird and depend on which order you take each. If you need or are already taking Neurontin and an opioid for pain there’s no way you’re going to understand this, but here it is:
Hydrocodone: Coadministration of Neurontin (125 to 500 mg; N=48) decreases hydrocodone (10 mg; N=50) Cmax and AUC values in a dose-dependent manner relative to administration of hydrocodone alone; Cmax and AUC values are 3% to 4% lower, respectively, after administration of 125 mg Neurontin and 21% to 22% lower, respectively, after administration of 500 mg Neurontin. The mechanism for this interaction is unknown. Hydrocodone increases gabapentin AUC values by 14%. The magnitude of interaction at other doses is not known.
Morphine: A literature article reported that when a 60-mg controlled-release morphine capsule was administered 2 hours prior to a 600-mg Neurontin capsule (N=12), mean gabapentin AUC increased by 44% compared to gabapentin administered without morphine (see PRECAUTIONS). Morphine pharmacokinetic parameter values were not affected by administration of Neurontin 2 hours after morphine. The magnitude of interaction at other doses is not known. —Neurontin PI sheet
It’s always a good idea to check for drug-drug interactions yourself. Just because most people in the crazy meds business know about really important interactions (e.g. MAOIs and a lot of stuff, warfarin and everything on the planet) doesn’t mean the person who prescribed your meds told you about them, or the pharmacist has all the meds you take at their fingertips like they’re supposed to. Or they have the time to do their jobs properly when not dealing with complete idiots or playing Angry Farmers on teh Faecesbooks.
Learn more about drug-everything interactions on our page of tips about taking crazy meds.
Name, Address, Serial Number (Generic and Overseas Availability)
Not including controlled/extended/sustained release suffixes (Efexor ER, Trevilor retard e.g.) or branded generics that are a hyphenate of the generic name and the drug company name (Apo-Citalopram e.g.).
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If you’re still feeling judgmental as well as just mental4, please boost or destroy my self-confidence by honestly (and anonymously) rating this article on a scale of 0 to 5. The more value-judgments the better, even if you can criticize my work only once.
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1 As well as being an indication of half of said conditions.
2 Based on Julien's calculations from A Primer of Drug Action, the half-life multiplied by five is the generally accepted estimate of how long it takes a single dose of any given drug to be eliminated from the blood stream/plasma of someone with a normal metabolism. That's also the rough estimate for steady state if they can't get, or won't provide a number for that.
3 For crazy meds. I have no idea what the average complete clearance is for other types of medications. For all I know there are drugs that utterly vanish from your system in under five passes, and others that won't let go of your squishy bits for years after you stop taking them.
4 Thank you! I'll be here all weak. Be sure to tip your content provider. And don't try the veal, it's cruelicious!
If you have any questions not answered here, please see the Crazymeds Neurontin discussion board. We welcome criticisms of the articles, notifications of bad links, site problems, consumer experiences with medications, etc. I’m not always able to write back. Hence I never answer questions about meds via e-mail that are answered by this or other articles. Especially if they have been repeatedly asked on the forum. That’s why we write these damn things. Questions about which meds are best for your condition should also be asked on the forum; because this is a free site, so the price of admission is making things easier for somebody else searching for the same answer. We don’t deal with children on the forum or in private because after doing this for ten years I don’t have the emotional stamina to deal with kids who have brain cooties. How to contact Crazymeds. — Jerod Poore, CME, Publisher Crazymeds (crazymeds.us)
Last modified on Thursday, 26 March, 2015 at 11:03:49 by JerodPoore
Neurontin, and all other drug names on this page and used throughout the site, are a trademark of someone else. Neurontin’s PI Sheet will probably have the name of the manufacturer and trademark owner (they’re not always the same company) at or near the very bottom. Or ask Google who the owner is. The way pharmaceutical companies buy each other and swap products like Monopoly™ real estate, the ownership of the trademark may have changed without my noticing. It may of changed hands by the time you finished reading this article.
All rights reserved. No warranty is expressed or implied in this information. Consult one or more doctors and/or pharmacists before taking, or changing how you take any neurological and/or psychiatric medication. Your mileage may vary. What happened to us won’t necessarily happen to you. If you still have questions about a medication or condition that were not answered on any of the pages you read, please ask them on Crazy Talk: the Crazymeds Forum.
The information on Crazymeds pertains to and is intended for adults. While some information about children and adolescents is occasionally presented (e.g. US FDA approvals), pediatric-specific data such as dosages, side effects, off-label applications, etc. are rarely included in the articles on drugs or discussed on the forum. If you are looking for information regarding meds for children you’ll have to go somewhere else. Plus we are big pottymouths and talk about S-E-X a lot. Know your sources! Nobody on this site is a doctor, a therapist, or a pharmacist. We don’t portray them either here or on TV. Only doctors can diagnose and treat an illness. While it’s not as bad as it used to be, some doctors still get pissed off by patients who know too much about medications, so tread lightly when and where appropriate. Diagnosing yourself from a website is like defending yourself in court, you suddenly have a fool for a doctor. Don’t be a cyberchondriac, thinking you have every disease you see a website about, or that you’ll get every side effect from every medication1. Self-prescribing is as dangerous as buying meds from fraudulent online pharmacies that promise you medications without prescriptions.
All information on this site has been obtained from the medications’ product information / summary of product characteristic (PI/SPC) sheets and/or medication guides - which is all you get from sites like WebMD, RxList, NAMBLA NAMI, etc., the sources that are referenced throughout the site, our personal experience and the experiences family, friends, and what people have reported on various reputable sites all over teh intergoogles. As such the information presented here is not intended as a substitute for real medical advice from your real doctor, just a compliment to it. You should never, ever, replace what a real doctor tells you with something from a website on the Internet. The farthest you should ever take it is getting a second opinion from another real doctor. Educate yourself - always read the PI/SPC sheet or medication guide/patient information leaflet (PIL) that comes with your medications and never ever throw them away. OK, you can throw away duplicate copies, but keep at least one, as that’s your proof of purchase of having taken a med in case a doctor doubts your medical history. Plus they take up less space than a bottle, although keeping one inside of a pill bottle is even better.
Crazymeds is not responsible for the content of sites we provide links to. We like them, or they’re paid advertisements, or they’re something else we think you should read to help you make an informed decision about a particular med. Sometimes they’re more than one of those things. But what’s on those sites is their business, not ours.
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‘Everything is true, nothing is permitted.’ - Jerod Poore
1 While there are plenty of books to help you with hypochondria, for some reason there’s not much in the way of websites. Then again, staying off of the Internetis a large part of curing/managing the disorder.
2 Remember kids, Microsloth operating systems are like TOS Star Trek movies with in that every other one sucks way, way more. With TOS Star Trek movies you don’t want to bother watching the odd-numbered ones. With Microsloth OS you don’t want to buy and install the even-numbered ones. Anyone who remembers ME and Vista knows what I mean.
3 Have I mentioned how open source operating systems for commercial applications is one of the dumbest ideas in the history of dumb ideas?* I don’t even need my big-ass rant any more. Heartbleed has made my case for me. And that’s just the one that got all the media attention. The very nature of an open source operating system makes security as much of an illusion of anonymity. Before you flip out too much: the domain Crazymeds is hosted on uses a version of SSL that is not affected by the Heartbleed bug. That’s one of the many reasons why I pay a lot of money and keep this site on Lunarpages.
* Yes, I know I’m using open source browsers. I also test the site using the now-defunct IE and Safari browsers. Their popularity - and superiority - killed IE and Safari, so that’s why I rely on the open source browsers. It’s like brand vs. generic meds. Sometimes the generic is better than the brand.