Anticonvulsants – gabapentin (Neurontin) and pregabalin (Lyrica)

What is it? Two prescription drugs that were originally developed to treat epilepsy (hence the name "anticonvulsants" or sometimes also "antiepileptic drugs"), but have since been found to be effective on some types of chronic pain. It is a type of drug that you are supposed to take regularly and not as and when you experience pain, partly because you are supposed to start on a low dose and build up to a high dose, although as often turns out to be the case with me, I'm so susceptible to side effects that moving up to a higher dose causes me more harm than good.

Does it work? Yes, if you have the right sort of pain and possibly also the right sort of physical make-up. Trial data seems to suggest, that even among people with neuropathic pain gabapentin and pregabalin work for some people and not for others. I take gabapentin and I find it effective at reducing my pain. Unfortunately it often doesn't clear it entirely and it comes with some pretty strong side effects. My personal experience is that it works from within minutes of me taking a pill (right from the first pill) and that when I first went on it and whenever I go up to a higher dose, it is highly effective and reduces most of my pain to practically zero, allowing me to lead a normal life and do what everyone else can do, but after I've been on it for about a week, it stops being nearly as effective and I go back to having to make choices between doing things and sleeping at night. However, even in this less effective state it is still a major improvement over not taking it and sleeping is much easier.

Who does it work for? Gabapentin is recommended for various types of neuropathic pain. Pregabalin is approved by the FDA for diabetic neuropathy and fibromyalgia. Given the similarity between the two drugs and the fact that gabapentin is fairly cheap and pregabalin is highly expensive, an NHS doctor is likely to try you on gabapentin first if either of these drugs is considered suitable for you. I specifically have a diagnosis of "not fibromyalgia" for my pain - it doesn't meet the criteria on several fronts. This leaves the possibilities that either this means some or all of my pain falls into the category of "neuropathy" or gabapentin also works for pain other than fibromyalgia and neuropathy for at least one person (and therefore conceivably for other people). My guess (and it is no more than that), is that it calms down my central nervous system and stops it making such a big deal out of pain, and therefore prevents or reduces pain that is due to an over-reaction of my central nervous system, which would fit with the idea of these drugs working on neuropathic (=nerve or nervous-system-related pain). At any rate, if your pain is at a level where you'd really appreciate another drug-based option, it's worth asking your doctor if you can try gabapentin. In my view (based on my own experiences) you should know somewhere between immediately and within a week whether you find it helps - depending on how much your pain normally fluctuates, I initially attributed my experiences with gabapentin to natural pain fluctuation and only became sure it was what was making the difference when I tried to come off it.
 
Who doesn't it work for? Theoretically at least, anyone whose pain is not caused by neuropathy or fibromyalgia. However, I've found a paper that suggests that neuropathic components are present in 20-35% of people with low back pain, so just because your pain appears to have a mechical and nociceptive cause (nociception = responding to harmful stimuli), this doesn't necessarily mean that there's not neuropathic element to it. In other words, unless there's a reason not to, if your other methods aren't producing sufficient pain relief, trying gabapentin or pregabalin on your pain may be helpful. But don't forget to come off it again if it doesn't work, as if you have chronic pain, you have enough trouble without taking drugs with no benefit for you.

Where can I get it?  Both gabapentin (Neurontin) and pregabalin (Lyrica) are prescription only drugs, at least in the UK, the US, Canada and Australia, so you'll need to get a prescription from your doctor. A GP can prescribe gabapentin.

How much does it cost? In the UK, because they are prescription-only drugs they both cost a prescription charge for 28 days' supply or however much your doctor prescribes in one go (unless you get free prescriptions or have a pre-payment certificate, in which case it is free). In 2012 300 mg of gabapentin 3x a day costs the NHS £143.91 per year per patient because it is off-patent. On the other hand, pregabalin in any dosage cost the NHS £722.80 per year per patient because it is still in patent for use on pain until July 2017 in the UK and December 2018 in the US. From August 2017 onwards it is to be assumed that a considerably cheaper generic version will become available in the UK. Until July 2017, an NHS doctor is considerably more likely to try you on gabapentin than pregabalin and is only likely to let you try pregabalin if gabapentin is problematic for you.

Is there a cheap or free version? Nope, there's just the option of buying a pre-payment certificate to cover all your prescription meds in the UK. If you're in a country where you pay a non-fixed price for prescription meds, it's worth knowing that the gabapentin (the non-brand name for Neurontin) is considerably cheaper than Neurontin (you're paying for the brand name), pregabalin (still in patent) or Lyrica (the brand name for pregabalin), but this may change in July 2017 in the UK and December 2018 in the US, when pregabalin comes off patent (although the brand name versions are likely to remain significantly more expensive than the non-brand-name versions).

What about side effects? Oh yes, there's plenty of those for both gabapentin and pregabalin, although not everyone gets them. My symptoms aren't listed as common, leaving me unsure whether they're genuinely not common or whether this is just due to the reporting system for side effects (I explain to my doctor or pharmacist what side effects I'm getting that aren't listed on the pack, my doctor or pharmacist explains why I'm wrong, 10 years later the side effects turn up on the patient information leaflet). I get significant memory loss, specifically in what I call my diary memory. I can remember new facts (e.g. that the Dutch for belt is ceintuur), but have difficulty remembering both what I have done (when did I last meet my friend Julie? I remember that I have met up with her several times in the past, but not how recently or what we did last time) and for things I am planning to do (sorry I forgot to turn up when we agreed to meet). It is less bad for things I do regularly, I am more likely to remember them. The one other person I know on a similar drug (pregabalin) also has the same sort of memory loss. However, this is only anecdotal evidence, and may indicate nothing beyond the response of two people. The other effects I get from gabapentin are what got it on the Talk to Frank website about recreational drug use. When I first go on it or if I increase my dose, I feel warm and fuzzy and highly contented emotionally. I then feel spaced, like I'm not quite in the present and my emotions are not quite linked to what's going on around me in real time. I think this is probably all intended to be covered by the "euphoria" side effect listed on the pack. This feeling continues if I remain on a high doses, but goes away after a few weeks on a low dose.
It also reduces my anxiety. You would think this would be a good thing, but actually I was already a fairly unanxious person without the drug, so this reduction also plays out as a reduction in me caring about most things, which feels to me like a fundamental change in my personality to the extent that I feel like a different person (I was previously a person who cared a lot about people and things), although that doesn't stop me getting mood swings and bouts of anger (hard to tell if that's just me, a reaction to my none-too-easy life circumstances or actually the drug).

The absolutely worst side effect I get is a massive increase in pain on some days, which may or may not relate to be forgetting to take a dose, my memory loss means I'm often not sure if I've taken it or not. It is this that truly makes 300mg 3x a day unbearable for me, as the days of massive pain are at a higher level on it. Based on trial data, it is, however, highly likely that some people will not get side effects at all. A review of the trials found that only 6 people in 10 experienced some adverse events, including dizziness (2 in 10), sleepiness/drowsiness (1 or 2 in 10), peripheral oedema (swelling/accumulation of fluid), problems walking (1 in 10).
The trick is a) to monitor what changes when you take it and b) decide if it's worth it for the side effects and consider coming (back) down to a lower level of it or coming off it. My experience tells me that just because it's not listed on the packet and just because your doctor and pharmacist don't believe you doesn't mean it's not a side effect, and if something unpleasant consistently happens while you are on it and not when you aren't, it's perfectly fair to count that as a reason against taking the drug. For an explanation of why this system of thinking isn't perfect see this article on the nocebo effect, but it's the best rule of thumb I have (especially after years of taking drugs that had bad side effects on me because I believed my doctors when they explained they weren't really side effects).

Is it addictive? What about withdrawal symptoms? It depends what you mean by addictive. If you mean, will you be so desperate to get your next fix of gabapentin or pregabalin that you'll steal money to fund your habit and you'll need an ever higher dose just to feel the same, then no it's not addictive (although for me the benefits of an increased dose quickly taper off, leaving only the side effects to endure). However, if you come off a high dose of it suddenly, you are likely to experience withdrawal symptoms (this is what doctors call being physically dependent on a drug rather than addicted to it). I accidentally misplaced my meds while abroad while I was on 300mg 3x a day (as I've mentioned, in my case it comes with a side helping of memory loss). For me this resulted in me not sleeping for 36 hours - it might have been longer had I not remembered where I'd put them and taken one. Here is a list of withdrawal symptoms for gabapentin:
* anxiety
* insomnia
* nausea
* pain
* sweating
* temporary increase in seizure symptoms
This makes me think that a) the days when I get a massive increase in pain are probably the days when I've forgotten a dose (and forgotten I've forgotten it) and could probably be countered by taking an extra dose and b) that it's far more sensible to come off slowly than fast. The recommendation is that you talk to your doctor so that you can come off it gradually. After years of going cold turkey on drugs that give you withdrawal symptoms, I can thoroughly recommend coming off things slowly. It does make a world of difference.

Is there any evidence for it?  Yes. One randomised, placebo-controlled trial of more than 100 patients per treatment arm found that 1800 to 3600 mg per day of gabapentin was effective and well tolerated in the treatment of adults with neuropathic pain. A review of the research found 37 studies of reasonable quality with 5633 participants testing gabapentin against placebo for four weeks or more. It found that only two conditions had useful amounts of data - postherpetic neuralgia (=chronic pain following shingles) and painful diabetic neuropathy. Gabapentin helped 3 or 4 people in 10 by reducing their pain by at least half, while with placebo only 2 in 10 had this result. I also found a review of the trials for pregabalin, which was quite a lengthy and complex read, but included statements such as that a pooled analysis showed that preagabalin at doses of 150, 300 or 600 mg per day was significantly better than placebo for diabetic peripheral neuropathy, with a median time of 4-5 days needed to see sustained improvement, but not all patients responded (number needed to treat was calculated to be 6 for 300 mg per day and 4 for 600 mg per day). From all that I take the message that it is more effective than placebo, but doesn't work for everyone, not even everyone who has neuropathic pain.

Are there any downsides? Yes. See lists of possible side effects (which for me are very major, but which may be minor or non-existant for others) and withdrawal symptoms, plus remembering to take it 2 or 3 times a day (depending on which one you take) plus any cost.

Are there any other upsides? It may also reduce anxiety, which may be a good thing if you are an anxious person (or not if you're not, depending on your point of view).

Is there anything else I should know? The recommendation with gabapentin and pregabalin is that you should take it regularly, start on a lower dose and gradually work your way up to a higher dose. If you are the sort of person who suffers a lot from side effects, a higher dose might not be suitable for you, so it might be better to stick to the lower dose. I found that the increased pain relief of the higher dose (like with my very first dose) arrived pretty much as soon as I took the first pill, but wore off after my body had habituated to it after a week or two, whereas the side effects endured. Because everyone reacts to meds differently, how it works for me might not be relevant to anyone else, but in case you are interested in how the med is for someone else, this is how it works best for me: I take 100mg 3 x a day most of the time, but take an extra pill on my bad days (e.g. 8 am 100 mg, 3 pm 100 mg, 10pm 200 mg). This has an immediate impact, and fortunately because it's such a small change is easy to come back off. I just go back down to 100 mg 3 x a day when I am ready, as this would in any case be the next step down if I were trying to taper my dose. In fact, the step would probably be from 200 mg 3x a day to 100mg 3x a day. My doctor tells me 100mg 3x a day is a dose I can just stop any time without withdrawal symptoms.

Was it worth the money? Yes, for me (although as I buy a prepayment certificate, that cost is only the gabapentin's share in what my prepayment certificate buys). My life is more unpleasant without gabapentin. I've tried it. (And I'll be trying pregabalin as soon as it comes off patent in July 2017.) However, if you don't get a noticeable benefit from it, or if the side effects make your life worse by more than the benefits make it better, then that changes the answer completely.

Do you use gabapentin or pregabalin for pain? What kind of pain does it help? How quickly did you notice the benefits? What side effects do you get? Have you tried both? If so, which do you find better?